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Implementation and evaluation of a hospital-based infant car restraint program Sax, Ronald Jeffrey 1984

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IMPLEMENTATION AND EVALUATION OF A HOSPITAL-BASED INFANT CAR RESTRAINT PROGRAM BY RONALD JEFFREY SAX B.Sc, The U n i v e r s i t y of Toronto, 1968 M.D., The U n i v e r s i t y of Toronto, 1972 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES (Department of Health Care and Epidemiology) (Health Services Planning and Administration Program) We accept t h i s t h e s i s as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA August 1984 ©Ronald J e f f r e y Sax, 1984 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study. I f u r t h e r agree t h a t permission f o r extensive copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the head of my department or by h i s or her r e p r e s e n t a t i v e s . I t i s understood that copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l gain s h a l l not be allowed without my w r i t t e n permission. Department Of Health Care & Epidemiology The U n i v e r s i t y of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 D a t e 24 September. 1984 DE-6 (3/81) Abstract The leading cause of death f o r c h i l d r e n under f i v e years of age i s motor v e h i c l e accidents. The use of approved car r e s t r a i n t s can reduce the mortality incidence by at l e a s t 50%, and the morbidity incidence by at l e a s t 70%. The current usage rate of car r e s t r a i n t s i n B r i t i s h Columbia i s approximately 50% f o r infants 6 months of age, f a l l i n g o f f to 10% f o r four year olds. This study was a prospective, before and a f t e r design evaluating an i n -h o s p i t a l program to educate new mothers on the benefits of using i n f a n t car r e s t r a i n t s . The program i s intended to be low cost and s e l f - f i n a n c i n g and consists of three components: an educational package on i n f a n t car r e s t r a i n t s i s d i s t r i b u t e d to a l l new mothers; a videotape presentation i s screened d a i l y on the post-partum ward; and i n f a n t car r e s t r a i n t s are s o l d at a discount i n the h o s p i t a l g i f t shop. Two community h o s p i t a l s i n the metropolitan Vancouver area p a r t i c i p a t e d i n the study. Baseline r e s t r a i n t use at each study s i t e was determined i n a preprogram group. A f t e r a short i n t e r v a l , the program was introduced and r e s t r a i n t use i n the program group was measured. I n i t i a l questionnaires were used to determine s e l f - r e p o r t e d r e s t r a i n t use and basic demographic information. Unobtrusive observations by h o s p i t a l s t a f f were used to v e r i f y r e s t r a i n t use. Follow-up mail questionnaires at s i x weeks post-partum were used to provide a d d i t i o n a l demographic and socio-economic information. A high response rate to the questionnaires was obtained from t h i s group of new mothers. A s u b s t a n t i a l bias i n s e l f - r e p o r t i n g of r e s t r a i n t use was a l s o found, but t h i s d i f f e r e d between the two h o s p i t a l s . i i i In h o s p i t a l s where currently only a minority of mothers use i n f a n t r e s t r a i n t s , t h i s program may s i g n i f i c a n t l y increase r e s t r a i n t usage. Compared to non-users, mothers who used i n f a n t r e s t r a i n t s tended to be s l i g h t l y older, better educated, married and les s l i k e l y to smoke. i v Table of Contents Page Abstract i i L i s t of Tables v i i L i s t of Figures v i i i Acknowledgement i x Chapter 1: Introduction 1 Chapter 2: L i t e r a t u r e Review 4 2.1 M o r t a l i t y and Morbidity of Children i n Motor Vehicles 4 2.2 E f f e c t i v e n e s s of Automobile Passenger Restraints: Adults 10 2.3 Effectiveness of Automobile Passenger Restraints: Infants and Children 11 2.4 Restraint Usage: Adults 17 2.5 Restraint Usage: Infants and Children 18 2.6 Strategies to Promote Restraint Use: L e g i s l a t i o n 19 2.7 Strategies to Promote Restraint Use: Information 21 2.8 Strategies to promote Restraint Use: Education 22 Chapter 3: Methodology 26 3.1 Educational Strategy 26 3.2 Design 28 3.3 Sample Si z e 28 3.4 Questionnaire 29 3.5 Program I n i t i a t i o n 30 3.6 Program Procedure 31 3.7 S t a t i s t i c a l A nalysis 34 V Page Chapter 4: Results 35 4.1 Questionnaire Response Rates 35 4.2 Missing Data 38 4.3 Comparability of H o s p i t a l Subject Populations 38 4.4 Comparability of Groups With Each Hospital 40 4.5 Restraint Use: Self-Report 40 4.6 Restraint Use: Observation 40 4.7 Inconsistency Between Self-Reported and Observed Restraint Use 40 4.8 Comparability of Consistent Subjects with Subjects Observed to be Not Consistent with respect to Self-Report 42 4.9 V a r i a b l e s Associated with Self-Report of Restraint Use 44 4.10 V a r i a b l e s Associated with Observed Restraint Use 44 Chapter 5: Discussion 48 5.1 Introduction 48 5.2 Questionnaire Response and Completion 48 5.3 C h a r a c t e r i s t i c s of the H o s p i t a l Subject Populations 50 5.4 Observed Restraint Use and Program Evaluation 50 5.5 V a l i d i t y of Self-Report 52 5.6 V a r i a b l e s Associated with Restraint Use 54 5.7 Summary 55 5.8 Planning Implications 56 v i Page References 57 Appendix I: Educational Package 63 Appendix I I : Sample Size Determination 65 Appendix I I I : i ) I n i t i a l Questionnaire: Pre-program 66 i i ) I n i t i a l Questionnaire: Program 67 i i i ) Cover L e t t e r : I n i t i a l Questionnaire 68 i v ) Follow-up Questionnaire 69 v) Cover L e t t e r : Follow-up Questionnaire 70 vi) Reminder L e t t e r : Follow-up Questionnaire 71 v i i ) Follow-up L e t t e r 72 Appendix IV: C e r t i f i c a t e of Approval 73 Appendix V: Comparability of H o s p i t a l Subject Populations: Pre-program Groups 74 Appendix VI: Comparability of Groups Within Each Hospital Separately 77 Appendix V I I : Comparability of Subjects Observed to Subjects Not Observed 83 Appendix V I I I : Comparability of Consistent Subjects and Subjects Observed to be Not Consistent with Respect to Self-Report 86 Appendix IX: Var i a b l e s P o s s i b l y Associated with Restraint Use: Self-Report 88 Appendix X: Var i a b l e s Possibly Associated with R e s t r a i n t Use: Observation 91 Appendix XI: Three-way Table: Observed Restraint Use, Family Income, Education 94 Appendix XII: Three-way Table: Self-Reported Restraint Use, Family Income, Education 96 v i i L i s t of Tables Page Table I Summary of Item Omissions Among I n i t i a l Questionnaire Responses 37 Table II Summary of Item Omissions Among Follow-up Questionnaire Responses 39 Table III Summary of Missing Observations of Restraint Use 39 Table IVa Self-Report of Restraint Use: Lions Gate 41 Table IVb Self-Report of Restraint Use: Surrey 41 Table Va Observed Restraint Use: Lions Gate 43 Table Vb Observed Restraint Use: Surrey 43 Table V i a Inconsistency i n Self-Reporting: Lions Gate 43 Table VIb Inconsistency i n Self-Reporting: Surrey 43 Table VII P-values f o r Chi-Square T e s t i n g of Vari a b l e s P o s s i b l y Associated with Self-Report of Restraint Use 45 Table VIII P-values f o r Chi-Square T e s t i n g of Vari a b l e s P o s s i b l y Associated with Observed Restraint Use 46 v i i i L i s t of Figures Page Figure 2.1.1 Age S p e c i f i c Death Rates Due to Monitor Ve h i c l e Accidents, Canada 1981 5 Figure 2.1.2 Occupant Deaths per 100,000 Populations Per Year, U.S.A., 1976-77 6 Figure 2.1.3 Basic " f i r s t " matrix f o r c l a s s i f i c a t i o n of road loss f a c t i o n s i n each of the three phases of i n t e r a c t i o n s that lead to the end r e s u l t s i n energy-damaged people and property 9 Figure 2.1.4 Basic matrix f o r c l a s s i f i c a t i o n of road loss f a c t o r s with a r b i t r a r y element ( c e l l ) numbers assigned f o r convenience of d e s c r i p t i o n 9 Figure 2.3.1 The Infant C a r r i e r 13 Figure 2.3.2 The C h i l d Safety Seat 14 Figure 2.3.3 Booster Cushions ' 15 Figure 2.3.4 Convertible Seats 16 Figure 3.6.1 I n i t i a l Questionnaire D i s t r i b u t i o n Periods 33 Figure 4.1.1 Questionnaire D i s t r i b u t i o n and Response 36 i x Acknowledgement I am greatly indebted to Dr. Ned G l i c k f o r suggesting that t h i s t o p i c could form the basis of a t h e s i s , and a l s o f o r h i s guidance, patience and f r i e n d s h i p over the course of time taken i n w r i t i n g . I would also l i k e to thank Dr. Sam Sheps and Dr. Roger Tonkin f o r t h e i r help, as members of the committee, i n the preparation of t h i s t h e s i s . A number of i n d i v i d u a l s and agencies were e s s e n t i a l i n conducting t h i s study. L e z l i e Wagman, Ju d i t h Mosoff and Sandra Kalmakoff helped i n data c o l l e c t i o n ; Wayne Jones and Helene Crepeau provided data a n a l y s i s . I would l i k e to acknowledge the support of the S a l v a t i o n Army Grace H o s p i t a l , Lions Gate H o s p i t a l , Surrey Memorial H o s p i t a l , Richport Ford, Ford Motor Company of Canada, Vancouver Health Department, Health Promotion Directorate, Health and Welfare Canada, and the many i n d i v i d u a l s i n these agencies who p a r t i c i p a t e d i n ca r r y i n g out t h i s study. This study was supported i n part by the Health Promotion Directorate, Health and Welfare Canada ( F i l e #6554-2-32). The views expressed herein are those of the author and do not n e c e s s a r i l y represent the o f f i c i a l p o l i c y of the Department of National Health and Welfare. 1 Chapter 1: Introduction Accidents are the leading cause of death f o r c h i l d r e n under f i v e years of age i n Canada, and about 25% of these accidental deaths occur to c h i l d motor vehicle passengers. In Canada i n 1981 the mortality rate from motor ve h i c l e accidents was 8.5 per 100,000 c h i l d r e n aged 1-4 years.^ (By contrast, the foremost non-accident mortality rate was 8.3 per 100,000 due to congenital anomalies.^) In B r i t i s h Columbia alone, 14 c h i l d passengers aged 1-4 years died i n motor vehi c l e accidents i n 1981 (mortality rate 9.2 per 100 ,00). 2 Although seat b e l t s are e f f e c t i v e i n p r o t e c t i n g older passengers, they are not u s u a l l y s u i t a b l e f o r c h i l d r e n under 5 years of age. Special car r e s t r a i n t s are needed f o r t h i s age group. Recent studies have demonstrated that use of such i n f a n t and c h i l d r e s t r a i n t s can s u b s t a n t i a l l y reduce i n j u r i e s i n motor v e h i c l e accidents, and hence can s u b s t a n t i a l l y reduce o v e r a l l morbidity and m o r t a l i t y among c h i l d r e n under 5 years.3/4 E f f o r t s to promote the use of appropriate c h i l d r e s t r a i n t s are somewhat d i s t i n c t from promotion of adult seat b e l t use. Most obviously, l e g i s l a t i o n requires that a l l new automobiles s o l d i n Canada are equipped with seat b e l t s but not with i n f a n t or c h i l d r e s t r a i n t s ; however, laws r e q u i r i n g mandatory use of these safety b e l t s have not r e s u l t e d i n f u l l compliance. The use of seat b e l t s by parents has been noted as a p r e d i c t o r of r e s t r a i n t use for t h e i r children; ^ '^ therefore, i n areas where adult seat b e l t use i s l e g i s l a t e d , and consequently higher, the use of i n f a n t and c h i l d car r e s t r a i n t s may also be higher. 2 Other e f f o r t s to promote i n f a n t and c h i l d r e s t r a i n t s have included insurance discounts, educational programs, and p u b l i c information campaigns. In general, programs aimed at s p e c i f i c groups (e.g. post-partum women) show a greater e f f e c t than mass media campaigns. Information imparted by a perceived 'health expert' (e.g. nurse, physician) appears to be more re a d i l y accepted. The format of the presentation (e.g. p r i n t e d material, f i l m or videotape, personal communication, etc.) may also a f f e c t the impact of a program. The present study describes and evaluates an i n - h o s p i t a l program to educate new mothers on the benefits of using i n f a n t car r e s t r a i n t s . The primary focus of the study was to determine what increase i n r e s t r a i n t use i s associated with the i n - h o s p i t a l program. In the course of t h i s determination the following questions were also addressed: What are current rates of use of i n f a n t r e s t r a i n t s f o r newborns immediately upon discharge from selected h o s p i t a l s i n the greater Vancouver region? What are the d i s t o r t i o n s i n s e l f - r e p o r t i n g of r e s t r a i n t use? Are there demographic and socio-economic factors which p r e d i c t r e s t r a i n t usage? The program was intended to be low-cost and s e l f - f i n a n c i n g and consisted of three components: 1. An educational package on i n f a n t car seats d i s t r i b u t e d to a l l new mothers; 2. A videotape (or film) presented d a i l y on the post-partum ward; 3. Infant car seats s o l d at a discount i n the h o s p i t a l g i f t shop. 3 The program was developed f o r use i n h o s p i t a l o b s t e t r i c wards. The use of an i n f a n t car r e s t r a i n t upon discharge was s e l f - r e p o r t e d by questionnaire (and v e r i f i e d by unobtrusive observation) during a pre-program and program period. Follow-up mail questionnaires were used to provide a d d i t i o n a l information about the subjects. The chapters which follow provide d e t a i l s about the development of the study. The l i t e r a t u r e review (Chapter 2) o u t l i n e s the problem of motor v e h i c l e accident mortality; the effectiveness of automobile passenger r e s t r a i n t s ; the compliance with r e s t r a i n t usage; and the s t r a t e g i e s to promote r e s t r a i n t use, e s p e c i a l l y i n the post-natal period. The methodology section (Chapter 3) d e t a i l s development of the research strategy; experience with community h o s p i t a l s i n i n i t i a t i n g the program; and s t a t i s t i c a l methods. De t a i l s of the r e s u l t s w i l l be presented i n Chapter 4 and the discussion (Chapter 5) w i l l examine these findings i n the context of previously reported studies. 4 Chapter 2: L i t e r a t u r e Review 2.1 M o r t a l i t y and Morbidity of Children i n Motor Vehicles The m o r t a l i t y rate due to motor v e h i c l e accidents f o r c h i l d r e n 1 to 4 years of age represents the leading cause of death f o r t h i s group. Eighty years a f t e r the introduction of the automobile i n North America, the number of people k i l l e d and i n j u r e d i n motor vehi c l e accidents represents a modern epidemic. In Canada i n 1982, 4,073 people were k i l l e d as passengers i n 7 motor v e h i c l e s . In B r i t i s h Columbia i n 1981, 14 c h i l d passengers were included among 694 deaths recorded f o r v e h i c l e occupants involved i n motor Q v e h i c l e crashes. These v e h i c l e occupant deaths and i n j u r i e s occur to a generally young and 'healthy* population. M o r t a l i t y rates (Canada 1981) from motor vehi c l e accidents^ are shown by age group i n Figure 2.1.1. Motor v e h i c l e accidents were the t h i r d leading cause of p o t e n t i a l years of l i f e l o s t (Canada 1980) a f t e r cancer and ischaemic heart disease. Baker^C1 analyzed motor v e h i c l e occupant deaths of U.S. c h i l d r e n aged 0 to 12 years (1976 and 1977). She found that the highest death rate was recorded f o r the youngest c h i l d r e n , those most dependent on t h e i r par-ents f o r protection (Figure 2.1.2). Baker f e l t that t h i s r e s u l t was unex-pected because Williams'1'' found i n a survey that very young c h i l d r e n were les s l i k e l y to be passengers i n cars than older c h i l d r e n . Combining t h i s low t r a v e l fequency and high death rate i n motor veh i c l e s indicates that when inf a n t s t r a v e l , they are at high r e l a t i v e r i s k of being k i l l e d . 1 2 6 A, Death rates f o r ages 0 to 11 years, with separate points f o r the f i r s t and second 6 months of l i f e . B, Death rates f o r ages 0 to 11 months. Baker^° 7 Baker suggests that, the high death rate i n i n f a n t s may be p a r t l y due to a greater l i k e l i h o o d of being i n the front seat and/or held i n someone's arms; both f r o n t seat p o s i t i o n and on-lap t r a v e l place c h i l d r e n at an increased r i s k of being i n j u r e d and k i l l e d . 1 0 A fur t h e r explanation of t h i s r e s u l t i s contained i n a study by Karwacki and Baker,^3 i n which they reviewed a s e r i e s of 89 motor v e h i c l e occupant deaths of persons le s s than 15 years o l d (Maryland, 1973 through 1977). Although c h i l d r e n l e s s than 1 year of age represented 2% of the c h i l d r e n i n crashes, they constituted 15% of the deaths. Karwacki and Baker i n d i c a t e d that, the predominance of head i n j u r i e s among very young c h i l d r e n suggests that t h e i r high death rates may be p a r t l y due to the f a c t that the head makes up a greater proportion of t h e i r body weight, thus in c r e a s i n g the tendency to move h e a d f i r s t i n the d i r e c t i o n of an impact.^3 3 Scherz analysed i n d e t a i l 39 c h i l d f a t a l i t i e s that occurred during the years 1977-1979 i n Washington State. He found that these f a t a l accidents, "usually occurred under ordinary circumstances, on dry roads, at low speeds during daylight hours and were unrelated to alcohol usage," i n marked contrast to conditions found f o r adult f a t a l i t i e s . Non-crash events may also r e s u l t i n deaths and i n j u r i e s to c h i l d passengers. W i l l i a m s ^ 4 reported on the problem of c h i l d r e n being k i l l e d when f a l l i n g from moving motor veh i c l e s not involved i n crashes. In 1978, t h i r t y - e i g h t deaths of t h i s nature were recorded i n the United States to c h i l d r e n under 5 years of age. In a l l of these cases, the c h i l d r e n were unrestrained. 8 AgrarJS reported on i n j u r i e s r e s u l t i n g from non-crash events, such as sudden stops, swerves and turns, as w e l l as movement by an unrestrained c h i l d within the v e h i c l e . The i n j u r i e s were incurred e i t h e r by e j e c t i o n from the v e h i c l e or impact within the i n t e r i o r of the v e h i c l e . Unrestrained c h i l d r e n i n cars may pose an a d d i t i o n a l hazard. H a l l and C o u n c i l , ^ reviewing c o l l i s i o n accounts i n North Carolina accident f i l e s f o r the f i v e years 1974-78, found that during t h i s period, an unrestrained c h i l d was the d i r e c t cause of a c o l l i s i o n i n 554 cases, and at l e a s t a c o n t r i b u t i n g f a c t o r i n 194 cases. These c o l l i s i o n s , which may have been prevented by appropriate r e s t r a i n t s , r e s u l t e d i n one death, 572 i n j u r i e s , and at l e a s t $4.1 m i l l i o n i n t o t a l damages. In considering these deaths and i n j u r i e s r e s u l t i n g from motor v e h i c l e accidents, Haddon^ d i f f e r e n t i a t e s between accident prevention and i n j u r y prevention. He states that beyond attempting to prevent crashes, other means can e f f e c t i v e l y reduce losses i n damaged people and property; i n other words, rather than focus e n t i r e l y upon the prevention of c o l l i s i o n s , we should look f u r t h e r i n t o e f f e c t i v e l y preventing the i n j u r i e s and deaths which r e s u l t from these events. To analyze the f a c t o r s involved i n a c o l l i s i o n , Haddon constructed a matrix (Figure 2.1.3) which i s u s e f u l i n c l a s s i f y i n g a l l aspects of motor ve h i c l e accidents, and developing e f f e c t i v e countermeasures. The time frame i s divided i n t o three phases: pre-crash, crash, and post-crash, while the factors are divided i n t o human, ve h i c l e and equipment, and environment. 9 Figure 2.1.3: Basic " f i r s t " matrix f o r c l a s s i f i c a t i o n of road loss factors i n each of the three phases of in t e r a c t i o n s that lead to the end r e s u l t s i n energy-damaged people and property. Factors Phases Human Vehicle and Equipment Environment Pre-Crash Crash Post-Crash Results Haddon 1 7 Figure 2.1.4: Basic matrix f o r c l a s s i f i c a t i o n of road loss factors with a r b i t r a r y element ( c e l l ) numbers assigned f o r convenience of de s c r i p t i o n . Factors Human Vehicle & Equipment Physical Environment Socio-l e g a l Pre-Crash 1 4 7 10 Crash 2 5 8 11 Post-Crash 3 6 9 12 Results (adapted from Haddon 1') 10 The usefulness of t h i s conceptual framework was s u c c i n c t l y stated by Haddon: Such matrices provide a means f o r i d e n t i f y i n g and considering, c e l l by c e l l , (a) p r i o r and pos s i b l e future resources a l l o c a t i o n s and a c t i v i t i e s , as w e l l as the e f f i c a c i e s of each; (b) the relevant research and other knowledge - both that already a v a i l a b l e and that needed f o r the future; and (c) the p r i o r i t i e s f o r countermeasures, judged i n terms of t h e i r costs and t h e i r e f f e c t s on undesirable i n j u r y r e s u l t s , that i s , on the problems to be reduced. 1 8 The environment component of the matrix might be furth e r subdivided i n t o p h y s i c a l and s o c i o - c u l t u r a l ( s o c i o - l e g a l ) f a c t o r s , and numbers may be assigned to each element ( c e l l ) to f a c i l i t a t e discussion (Figure 2.1.4). These numbers w i l l be used i n the text below. This study w i l l focus p r i m a r i l y on element 1 (Pre-Crash/Human) with respect to implementing a program designed to increase i n f a n t r e s t r a i n t use. The successful r e s u l t of the program would see infants protected by proper car r e s t r a i n t s , a r e s u l t which would be r e f l e c t e d within element 2 (Crash/Human) by reducing deaths and i n j u r i e s . 2.2 Effectiveness of Automobile Passenger Restraints; Adults Within element 2, Haddon 1 7 considers the great resistance of the human body, when properly packaged, to the forces occurring at impact. The use of safety b e l t s by adult automobile passengers can e f f e c t i v e l y reduce the number of deaths and i n j u r i e s r e s u l t i n g from motor vehi c l e accidents. This would correspond to the "properly packaged human body" r e f e r r e d to by Haddon. Reductions i n (non-fatal) i n j u r i e s of 30% to 90%, and reductions i n deaths of 40-50% have been reported f o r passengers wearing seat b e l t s i n motor v e h i c l e accidents when compared to passengers not wearing seat b e l t s . 1 9 - 2 3 11 There i s a general increased effectiveness when a shoulder b e l t i s used i n conjunction with a lap b e l t . A U.S. Department of Transport Study Report 2^ ind i c a t e d that the lap and shoulder b e l t combination i s about 60% e f f e c t i v e i n preventing f a t a l i t i e s . Robertson 2^ explained how systematic er r o r i n studies can over-estimate, as w e l l as underestimate, the effectiveness of safety b e l t s . Using data from three American states, he estimated that lap and shoulder b e l t s were e f f e c t i v e i n reducing f a t a l i t i e s by 50%. 2.3 Effectiveness of Automobile Passenger Restraints; Infants and Children The use of standard car safety b e l t s , however, i s not appropriate f o r most passengers under 5 to 6 years of age. In many j u r i s d i c t i o n s (including B r i t i s h Columbia) l e g i s l a t i o n r e q u i r i n g the use of safety b e l t s s p e c i f i c a l l y excludes passengers under a c e r t a i n a ge. 2 6 The reason behind t h i s exclusion i s based on body dimensions, biomechanics, and the physiology of bone growth of children.27 As a r e s u l t , s p e c i f i c r e s t r a i n t s have been designed and engineered f o r infants and c h i l d r e n , and these devices are subject to a government safety standard. In Canada, from 1974 to 1981, c h i l d r e s t r a i n t devices, f o r chi l d r e n between 9 and 18 kg, were regulated by the f e d e r a l Department of Consumer and Corporate A f f a i r s under the Hazardous Products Act. In A p r i l 1981, r e s p o n s i b i l i t y f o r c h i l d r e s t r a i n t standards was assumed by the Department of Transport. Safety standards have been developed f o r r e s t r a i n t s f o r c h i l d r e n l e s s than 9 kg (infant c a r r i e r s ) ( F i g . 2.3.1), between 9 and 18 kg ( c h i l d r e s t r a i n t s ) ( F i g . 2.3.2) and f o r c h i l d r e n over 18 kg ( F i g . 2.3.3) (booster cushions). A convertible seat model can be used from b i r t h u n t i l the c h i l d weighs 18 kg ( F i g . 2.3.4). 12 The effectiveness of these r e s t r a i n t s has been the subject of several studies. Scherz reviewed motor v e h i c l e accident reports over a ten year period (Jan. 1, 1970 t o Dec. 31, 1979) i n Washington state. Approximately 39,500 c h i l d passengers aged 0 to 4 years were involved i n these accidents, and 148 deaths were recorded. Of the 39,500 c h i l d r e n , approximately 6,300 (16%) were using some type of safety r e s t r a i n t , and only 2 deaths were recorded f o r t h i s group (1:3,150). Of the remaining 33,200 ch i l d r e n who were unrestrained, 146 deaths were recorded (1:227). This represents a r e l a t i v e r i s k of 13.9. Scherz concludes that i f a l l the c h i l d r e n had been wearing r e s t r a i n t s , there would have been 93% fewer deaths. Williams and Zador 4 reviewed North Carolina accident records f o r 1973 and 1974 i n which a 1967 and l a t e r model car was involved. They recorded 26,971 passengers under 15 years of age i n these events. They found that r e s t r a i n e d c h i l d r e n occupying the back seat were l e a s t l i k e l y to be injured; whereas unrestrained c h i l d r e n i n the front r i g h t seating p o s i t i o n were most l i k e l y to be in j u r e d . Greater than 90% of the c h i l d passengers i n these crashes were unrestrained. The use of r e s t r a i n t s reduced the in j u r y rate by 39% i n the f r o n t seat and 31% i n the back. Restraint use included both seat b e l t s and i n f a n t / c h i l d r e s t r a i n t s . C h r i s t o p h e r s o n 2 9 found that r e s t r a i n e d c h i l d r e n i n cars exhibited higher l e v e l s of appropriate or safe behaviour than unrestrained c h i l d r e n , and that the l e v e l of appropriate behaviour improved dramatically when car seats were introduced to c h i l d r e n who had not used them previously. Besides p r o t e c t i n g the c h i l d , the prevention or reduction of di s r u p t i v e behaviour i s an a d d i t i o n a l b e n e f i t f o r using proper r e s t r a i n t s . Figure 2.3 .1 : The Infant C a r r i e r 2 8 THE INFANT CARRIER Children under 9 kg (20 lbs) In i n f an t c a r r i e r s e s p e c i a l l y d e s i g n e d f o r c h i l d r e n f r o m b i r t h to 9 k g , the b a b y f a c e s the r ea r of t he c a r a n d is s e c u r e l y h e l d in the sea t b y t he h a r n e s s . T h e s ea t i t se l f is a n c h o r e d by the c a r s ea t be l t to p r e v e n t it f r o m m o v i n g d u r i n g a n a c c i d e n t o r s u d d e n s t o p . A l t h o u g h as a g e n e r a l r u l e c h i l d r e n s h o u l d a l w a y s r i de in the b a c k seat of a ca r , the r e a r - f a c i n g i n f a n t c a r r i e r m a y be u s e d in the f ront sea t w h e n y o u a r e t r a v e l l i n g a l o n e . T h i s a l l o w s y o u to c h e c k o n the c h i l d w i t h o u t t a k i n g y o u r a t t e n t i o n off d r i v i n g . 14 Figure 2.3.2: The C h i l d Safety_Seat 28 STATION WAGON , TRUCK The (ether strap must always be securely attach-ed to a bolt installed In the rear shetf of a car, or on the floor of a van, station wagon or hatchback. Some automobile manufacturers provide pre-(nstalted anchorage locations. THE CHILD SAFETY SEAT Toddlers 9 to 18 kg (20 to 40 lbs) There are a number of child safety seats on the market for children weighing between 9 kg and 18 kg . They are usually forward-facing and must be installed according to the manufacturer's instructions, preferably in the back seat. The seat has a harness to spread the impact force of a collision over the strongest parts of the child's body. The child safety seat is anchored to the car seat by an adult lap belt. A tether strap prevents the top of the seat from flying forward. Check the manufacturer's instructions for methods of installing the tether strap in your vehicle. F i g u r e 2.3.3: B o o s t e r C u s h i o n s 2 8 15 L A P B E L T S A N D B O O S T E R C U S H I O N S Chi ldren who have outgrown their child seats. For small children, a booster seat will improve their view and help position the lap belt properly over the hips. Booster cushions meeting federal government safety regulations will be available for sale in Canada in 1983. Make sure that your children always ride In the back seat and take care to position their lap belts snug and low on the hips; not against the tummy. 16 F i g u r e 2 . 3 . 4 : C o n v e r t i b l e S e a t s 2 8 CONVERTIBLE SEATS Birth to 18 kg (40 lbs) Convertible child safety seats can be used for the baby as a rear-facing infant carrier and. when the child is older, as a front-facing safety seat. When used in the forward-facing position, they are secured with the lap belt and the top tether strap as specified in the manufacturer's installation instructions. Be sure to adjust all harness straps properly to secure the child comfortably. If no child seat Is available, use a seat belt; it is safer for toddlers and young children to use a regular lap belt than no restraint at all. 17 2.4 Restraint Usage: Adults Haddon 3 0 d i f f e r e n t i a t e s between ac t i v e and passive interventions to reduce death and i n j u r i e s from automobile accidents. The use of seat b e l t s and c h i l d r e s t r a i n t s would be categorized by Haddon as an "active" approach; that i s , a c t i o n by the i n d i v i d u a l i s required to make the r e s t r a i n t e f f e c t i v e . The "passive" approach i n t h i s case would be automatic r e s t r a i n t s , such as a i r bags, or v e h i c l e designs which could better d i s s i p a t e crash forces both i n t e r n a l and external to the passenger compartment. 2 6 Haddon states that, H i s t o r i c a l l y , adequate success through a c t i v e approaches has been rare, and requires exceptionally broad understanding and strong motivation on the part of those involved. In sharp contrast, passive approaches, when a v a i l a b l e , and once i n i t i a t e d , have a spectacularly more successful r e c o r d . 3 0 In view of t h i s f a c t , he suggests that when an e f f e c t i v e passive approach i s a v a i l a b l e i t should be adopted (e.g. a i r bags). I f the passive approach i s not a v a i l a b l e , then a c t i v e measures should be maintained (e.g. seat b e l t s ) . The two approaches may be combined. The Canadian experience confirms Haddon's statement about the success of a c t i v e approaches. Despite the a v a i l a b i l i t y now of seat b e l t s as standard equipment i n a l l new cars i n the Canadian market, and s o l i d evidence of e f f e c t i v e n e s s , t h e i r use remains low. A 1981 survey by Tansport Canada 3 1 estimated a national average of 38.1% of d r i v e r s wearing shoulder b e l t s . The f i g u r e s ranged from a low of 3.4% i n Prince Edward Island to 52.5% i n Ontario. The 1981 national f i g u r e was s l i g h t l y lower than the 42.7% estimate i n 1979 (range: 4.8% i n Newfoundland to 60.9% i n 18 Saskatchewan). 31 Generally, passengers are l e s s l i k e l y to use safety b e l t s than d r i v e r s , and c h i l d r e n f a r less s o . 2 5 These estimates include four provinces with mandatory seat b e l t l e g i s l a t i o n (Ontario, Quebec, Saskatchewan and B r i t i s h Columbia). Robertson 2 5 estimated that l e s s than one t h i r d of U.S. drivers used seat b e l t s ; and Z i e g l e r 3 2 reported usage rates f o r various countries i n c l u d i n g A u s t r a l i a , 25% (1971); France, 26% (May 1973); Sweden, 35% (1975); I s r a e l , 8% (June 1975); United States, 20% (1975). 2.5 Restraint Usage; Infants and Children The use of an i n f a n t car r e s t r a i n t i s an a c t i v e intervention on the part of a parent or adult, although i t represents a passive measure from the c h i l d ' s perspective. Usage rates f o r these r e s t r a i n t s also confirm Haddon's s c e p t i c a l view of a c t i v e approaches. Reports from the United S t a t e s 3 3 - 3 7 have found i n f a n t r e s t r a i n t usage rates of 15% to 30%. An observational study by B.C. Research i n August 1982 prepared f o r the Insurance Corporation of B r i t i s h Columbia 3 8 found 53% of the c h i l d r e n 1-6 months of age i n a r e s t r a i n t . This increased to 73% f o r the age group 13-18 months but then declined to 10% f o r c h i l d r e n aged 4-5 years. The usage of car r e s t r a i n t s d i f f e r e d s u b s t a n t i a l l y among geographic zones. In the Greater Vancouver region (urban) over 50% of a l l c h i l d r e n under 6 years were i n r e s t r a i n t s whereas i n Northern B r i t i s h Columbia (rural) usage was barely one t h i r d . ( Reports a l s o suggest that i n f a n t r e s t r a i n t s , when used, are not used p r o p e r l y . 3 9 - 4 3 Improper use may include the following: wrong p o s i t i o n i n g of the r e s t r a i n t ; f a i l u r e to attach the r e s t r a i n t with the car safety b e l t ; improper p o s i t i o n i n g of the r e s t r a i n t harness, etc. These 19 reports c a l l a t t e n t i o n to the f a c t that compared to car safety b e l t s , there i s a greater p o t e n t i a l f o r improper use of i n f a n t car r e s t r a i n t s and e s p e c i a l l y c h i l d r e s t r a i n t s (improper or lack of attachment of the tether s t r a p ) . 2.6 Strategies to Promote Restraint Use; L e g i s l a t i o n In an e f f o r t to increase the use of seat b e l t s and car r e s t r a i n t s , various s t r a t e g i e s have been used. Haddon 3 0 predicted that strong motivation would be required to ensure adequate success through a c t i v e approaches. The enactment of laws r e q u i r i n g mandatory use of these devices (element 10, Pre-crash/Socio-legal) i s viewed as a strong motivator and has been quite widespread. In Canada, seven provinces have compulsory seat-belt l e g i s l a t i o n , and one province i s planning to introduce i t . Only A l b e r t a and New Brunswick do not have such l e g i s l a t i o n or plans to introduce i t . Williams and Robertson 4 1* observed daytime seat-belt use i n Vancouver before and a f t e r enactment of belt-use l e g i s l a t i o n i n B r i t i s h Columbia. Seat-belt use by dr i v e r s increased from 32% i n March 1975 to 50% i n September 1977 (the week before passage of the law), and 79% i n October 1977 (the week a f t e r passage of the law). The rate declined to 67% s i x months l a t e r and 66% nine months a f t e r enactment. A 1981 Transport Canada survey 3 1 estimated shoulder b e l t use i n B r i t i s h Columbia at 42.4%. Transport Canada31 estimated shoulder b e l t use i n Ontario at 52.5 percent i n 1981, the highest rate f o r any province. This survey estimated that shoulder b e l t use by dr i v e r s i n provinces with seat b e l t l e g i s l a t i o n was 46.8 percent, compared to 9.4 percent i n provinces without such l e g i s l a t i o n . Z i e g l e r 3 2 reviewed the e f f e c t of safety b e l t usage laws i n 17 countries and 2 provinces (Ontario, Quebec). In a l l cases, safety b e l t use 20 rose considerably a f t e r the introduction of l e g i s l a t i o n . I t was concluded that laws which were continuously enforced and provided f o r s i g n i f i c a n t p enalties f o r non-compliance were more e f f e c t i v e than those which were less rigorously enforced. W i l l i a m s 2 6 reported that most of the seat b e l t l e g i s l a t i o n enacted i n the 1970's exempted c h i l d r e n of various ages. In some cases, a d d i t i o n a l l e g i s l a t i o n has been enacted to r e c t i f y t h i s s i t u a t i o n . The seat b e l t l e g i s l a t i o n passed i n Ontario i n 1976 exempted persons le s s than 5 years of age or under 50 pounds (23 kg) i n weight. A b i l l passed i n 1982 now requires mandatory r e s t r a i n t use to protect these c h i l d passengers. L e g i s l a t i o n r e q u i r i n g c h i l d r e s t r a i n t use i s now i n e f f e c t i n four provinces (Ontario, Quebec, Saskatchewan and Newfoundland). In the United States, f o r t y states have enacted such l e g i s l a t i o n as of June 1983. The s i g n i f i -cance of t h i s l e g i s l a t i o n i n the U.S. i s borne by the f a c t that only one state (New York, 1984)has enacted mandatory seat b e l t use laws f o r passengers older than 5 years of age. The e f f e c t of c h i l d r e s t r a i n t laws i n Tennesee and Rhode Island has been reported.33-35 The r e s u l t s i n d i c a t e that r e s t r a i n t use increased a f t e r the l e g i s l a t i o n was enacted, and that these increases were greater than those experienced i n neighbouring states (Kentucky and Massachusetts) without such l e g i s l a t i o n . I t appears that l e g i s l a t i o n can be somewhat e f f e c t i v e i n in c r e a s i n g the usage rates of seat b e l t s and c h i l d r e s t r a i n t s , although the behaviour of a large number of passengers w i l l remain unaffected. Combining l e g i s l a t i o n with other programs may increase the e f f e c t of the former. In a study prepared f o r the U.S. Department of T r a n s p o r t a t i o n , 4 5 Marzoni concluded that, "simultaneous and p e r s i s t e n t exertion of a number of d i f f e r e n t program 21 e f f o r t s o f f e r s the best promise f o r a gradual, p o s s i b l y a c c e l e r a t i n g , change — p r i m a r i l y among selected target groups of d r i v e r s . " 2.7 Strategies to Promote Restraint Use: Information Pub l i c information campaigns employing mass media have been used to promote r e s t r a i n t use (element 1, Pre-crash/Human). A $51 m i l l i o n a d v e r t i s i n g campaign was undertaken i n the United States i n 1968 by the National Safety C o u n c i l . 4 6 ' 4 7 There was no change i n sel f - c l a i m e d use of safety b e l t s a f t e r the end of the program. I t was l a b e l l e d ACL "advertising's biggest f l o p " by Marketing/Communications magazine. Robertson et a l . 4 7 also reported that a c o n t r o l l e d study of the e f f e c t of t e l e v i s i o n messages on safety b e l t use showed no e f f e c t . N i c h o l s 3 6 reports a modest increase i n safety b e l t usage as a r e s u l t of mass media campaigns i n several European countries (e.g. B r i t a i n , Sweden, France, Holland). Although the campaigns r a i s e d usage rates to only about 30% of d r i v e r s , Nichols points out that these programs were valuable i n f a c i l i t a t i n g passage of safety b e l t l e g i s l a t i o n . Nichols a l s o c i t e s two examples of mass media e f f o r t s to increase c h i l d r e s t r a i n t usage. In Tennessee and New South Wales, A u s t r a l i a , p u b l i c information campaigns were developed i n conjunction with the passage of c h i l d r e s t r a i n t l e g i s l a t i o n . As a r e s u l t , the e f f e c t of the campaigns i s confounded with the e f f e c t of the l e g i s l a t i o n and a c l e a r evaluation of the impact of each separately i s not p o s s i b l e . I t would appear, however, that these campaigns alone are not greatly successful i n encouraging safety b e l t usage. 2.8 Strategies t o Promote Restraint Use; Education The i n e f f e c t i v e n e s s of mass media campaigns has l e d to more s p e c i f i c e f f o r t s d i r e c t e d at a p a r t i c u l a r target group. A number of programs promoting i n f a n t / c h i l d r e s t r a i n t s aimed at the i n d i v i d u a l parent have been r e p o r t e d . 3 9 ' 4 0 ' 4 2 ' 4 8 - 5 4 Generally these e f f o r t s have occurred i n a h o s p i t a l or p e d i a t r i c o f f i c e s e t t i n g , and the methods employed include promotional displays, educational hand-outs, f i l m or videotape presentations, counselling sessions, and demonstrations. In many cases r e s t r a i n t s are also made a v a i l a b l e f r e e , at reduced cost, or on loan. Several i n v e s t i g a t i o n s have focussed on counselling e f f o r t s i n the p e d i a t r i c o f f i c e s e t t i n g . 4 2 ' 4 8 - 5 u In one of the e a r l i e s t reports (1964), Bass and W i l s o n 4 8 found that counselling by a p e d i a t r i c i a n (during a normal o f f i c e v i s i t ) i n conjunction with two follow-up l e t t e r s r e s u l t e d i n a larger percentage of parents reporting the i n s t a l l a t i o n of seat b e l t s i n t h e i r cars (43%) compared to those who received only the l e t t e r s or no information at a l l (15.3 to 19.6%). S c h e r z 4 9 reported that counselling by a physician or nurse at a four week c l i n i c v i s i t , i n a d d i t i o n to exposure to a display and pamphlet, increased parent compliance i n the use of i n f a n t r e s t r a i n t s twice that of parents exposed to no information, the display alone, or the display and pamphlet. Scherz also found i n h i s study that 96% of infants i n safe r e s t r a i n t s at eight weeks were also transported s a f e l y at 9-12 months of age. Kanthor 4 2 studied the e f f e c t of car safety counselling during a prenatal p e d i a t r i c interview. At the six-week w e l l - c h i l d v i s i t , car 23 r e s t r a i n t usage was reported by 69% of the counselled mothers and 42% of the non-counselled mothers. M i l l e r and P l e s s 5 0 compared several methods of i n s t r u c t i o n concerning car r e s t r a i n t s i n the p e d i a t r i c o f f i c e s e t t i n g . The parents i n the experimental group received e i t h e r a pamphlet alone, a pamphlet and verbal i n s t r u c t i o n by the physician, or a pamphlet, verbal i n s t r u c t i o n and a slide-tape show. The co n t r o l group received no i n s t r u c t i o n . Although car r e s t r a i n t use reported two weeks a f t e r the v i s i t showed no s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e between groups, the highest mean score was received by the group that received a l l forms of i n s t r u c t i o n . The study was perhaps hampered by a r e l a t i v e l y high baseline usage rate (69%) and the short (two-week) time between int e r v e n t i o n and follow-up. In general, there was an increased compliance i n the use of r e s t r a i n t s by parents who had been counselled compared to those who had not. Although these r e s u l t s are encouraging, other studies have pointed out that less than 5 percent of physicians always advised t h e i r patients about auto safety practices. 5^#52 The h o s p i t a l maternity ward has also been studied as a s e t t i n g f o r counselling s t r a t e g i e s . A l l e n and Bergman 5 3 found that reported r e s t r a i n t usage f o r three groups exposed to educational programs ( i ) a one-page handout; i i ) the handout and viewing of a f i l m ; i i i ) the handout, f i l m viewing and p r a c t i c i n g with an i n f a n t r e s t r a i n t ) showed a marked increase over usage reported by a control group which received no education. Members of the experimental groups, however, had volunteered to p a r t i c i p a t e i n t h i s study. 24 Claimed safety b e l t and r e s t r a i n t use may be used as an i n d i c a t o r of actu a l use, but s e l f - r e p o r t i n g i s subject to a systematic o v e r e s t i m a t i o n . 2 5 » 51#55-58 Several studies conducted i n the h o s p i t a l s e t t i n g have used actual observation to determine corr e c t car r e s t r a i n t u s a g e . 3 9 ' 4 0 ' 5 4 Reisinger and W i l l i a m s , 3 9 reported on three groups of post-partum women exposed to i n - h o s p i t a l education programs. One group received p r i n t e d material and were advised that i n f a n t r e s t r a i n t s were a v a i l a b l e f o r purchase i n the h o s p i t a l ; a second group received the same information i n addition to a ten minute discussion on car safety with a health educator; a t h i r d group received the p r i n t e d material and an o f f e r of a free r e s t r a i n t . A comparison group received no education, although i n f a n t r e s t r a i n t s were a v a i l a b l e f o r purchase at the h o s p i t a l g i f t shop. Unobtrusive observations were made upon discharge from h o s p i t a l and two to four months l a t e r . The programs r e s u l t e d i n higher r e s t r a i n t usage rates but had l i t t l e or no e f f e c t on the rate of correct use. Reisinger and a s s o c i a t e s 5 4 studied the e f f e c t s of physician counselling of mothers i n the post-partum period on the use of infant r e s t r a i n t s . The experimental group received educational advice during the post-partum h o s p i t a l stay and at the one and two month w e l l - c h i l d v i s i t s . The educational methods included counselling, a pamphlet, a car r e s t r a i n t p r e s c r i p t i o n , and a demonstration of corre c t use of a r e s t r a i n t . The comparison group received none of t h i s educational input. Observations of r e s t r a i n t use were recorded during the w e l l - c h i l d v i s i t s at one, two, four, and f i f t e e n months. Correct r e s t r a i n t use was higher f o r the experimental group i n i t i a l l y (50% vs. 29% f o r the comparison group at two months) but the d i f f e r e n c e had diminished by four months (47% vs. 43% f o r the comparison group). The r e l a t i v e l y high usage rates were l i k e l y a r e s u l t of the f a c t that the subjects were mostly middle and upper-middle cl a s s women. Christopherson and S u l l i v a n 4 0 used a maternity ward s e t t i n g to study the e f f e c t of h o s p i t a l s t a f f input on the use of in f a n t r e s t r a i n t s . Subjects i n the co n t r o l group received no s p e c i a l a t t e n t i o n or education, whereas mothers i n the experimental group were of f e r e d a free loaner r e s t r a i n t and a demonstration of i t s correct use by a member of the h o s p i t a l s t a f f . Upon discharge correct r e s t r a i n t use was observed f o r 67% of experimental group in f a n t s but f o r none (0%) of the cont r o l group i n f a n t s . At the four to s i x week followup v i s i t , no s i g n i f i c a n t d i f f e r e n c e was observed (29% experimental vs. 23% c o n t r o l ) . This study h i g h l i g h t s the impact that h o s p i t a l personnel can have on in f a n t r e s t r a i n t use at l e a s t i n the short-term. Educational programs reported i n the l i t e r a t u r e i n d i c a t e that these e f f o r t s can be successful, and c e r t a i n aspects of the various methodologies may enhance the l i k e l i h o o d of success. Programs should begin as early as possible i n the prenatal p e r i o d 4 2 and the message, conveyed by a v a r i e t y of m e d i a , 4 2 ' 4 8 - 5 0 ' 5 3 should be repeated at several points i n t i m e . 5 4 The message should stress the p o s i t i v e aspects of the many r e s t r a i n t s as opposed to "scare t a c t i c s . " Advice by health personnel, e s p e c i a l l y nurses and physicians, should r e i n f o r c e other e f f o r t s , 4 8 ' 4 9 and r e s t r a i n t s should be e a s i l y a c c e s s i b l e . 3 9 ' 4 0 Educational programs alone w i l l not r e s u l t i n t o t a l compliance i n the use of in f a n t r e s t r a i n t s , but when combined with other interventions, such as l e g i s l a t i o n , r e s t r a i n t use can be increased s u b s t a n t i a l l y . 26 Chapter 3: Methodology This study was a prospective c o n t r o l l e d design evaluating an in - h o s p i t a l program to educate new mothers on the benefits of using i n f a n t car r e s t r a i n t s . The program was intended to be low-cost and s e l f f i n ancing and consisted of three components: an educational package d i s t r i b u t e d to a l l new mothers; a f i l m (or videotape) presented d a i l y on the post-partum ward; and i n f a n t car r e s t r a i n t s s o l d at a discount i n the h o s p i t a l g i f t shop. These components were i d e n t i f i e d as successful s t r a t e g i e s i n a review of the l i t e r a t u r e . 3.1 Educational Strategy Educational e f f o r t s which begin early i n the course of a pregnancy (e.g. prenatal v i s i t s , prenatal classes) may show a greater e f f e c t . 4 2 Intervention at an e a r l i e r time, however, would require a greater e f f o r t to reach the target population which i s widely dispersed. A large percentage of pregnant women ( e s p e c i a l l y those pregnant f o r a second and subsequent time) do not attend prenatal classes. Also, a focus on the prenatal period would bypass a large number of women who are i n the l a t e r stages of pregnancy. In consideration of these f a c t s , the program was d i r e c t e d at post-partum women, an e a s i l y accessible group, confined to o b s t e t r i c wards i n major h o s p i t a l s . A package of pr i n t e d material (Appendix I) and a f i l m (or videotape) presentation were used to convey the educational message. The p r i n t e d package stressed the p o s i t i v e aspects of using i n f a n t and c h i l d r e s t r a i n t s . The pro j e c t slogan, "Security i s more than a teddy bear," and logo (a toy bear i n a s t y l i z e d r e s t r a i n t ) implied that a r e s t r a i n t i s a natural progression i n providing s e c u r i t y f o r a new-born. The slogan and logo were adopted from the South C a r o l i n a C h i l d Safety Seat P r o j e c t . 5 9 The introduction sheet outlines the danger of c h i l d r e n t r a v e l l i n g unrestrained i n cars, and points out that i n f a n t r e s t r a i n t s reduce t h i s r i s k . I t l i s t s the options a v a i l a b l e l o c a l l y f o r obtaining r e s t r a i n t s . A "myth/fact" sheet d i s p e l s the most commonly believed myths concerning the safety of c h i l d r e n as motor v e h i c l e occupants. I t concludes that, "the only secure place f o r a c h i l d i n a car i s i n a crash-tested safety seat ... and that's a f a c t . " A t h i r d sheet r e p r i n t s a newspaper column (Dear Abby) of p o s i t i v e responses to a previous l e t t e r about the death of an unrestrained c h i l d . A government pamphlet 2 8 provides a general overview of the problem and a d e s c r i p t i o n and p i c t u r e of the types of r e s t r a i n t s a v a i l a b l e f o r infants and c h i l d r e n . I t also l i s t s p o s s i b l e sources f o r obtaining seats. In a d d i t i o n to the p r i n t e d material, a 15-minute f i l m (or videotape) e n t i t l e d " L i f e i s Precious. Buckle Them I n " 6 0 was screened d a i l y on the post-partum ward. The f i l m , narrated by a p e d i a t r i c i a n , h i g h l i g h t s the "human c o l l i s i o n " i n motor v e h i c l e accidents, and i l l u s t r a t e s the proper r e s t r a i n t s f o r d i f f e r e n t age groups. Infant car seats were s o l d within the h o s p i t a l at a s l i g h t discount compared to regular r e t a i l o u t l e t s . A small mark-up on the car seat covered the p r i n t i n g costs f o r the educational packages. 28 3.2 Design The study used a prospective, before and a f t e r design. Baseline r e s t r a i n t use at each study s i t e was determined i n a c o n t r o l (pre-program) group. A f t e r a short i n t e r v a l , the program was introduced and r e s t r a i n t use i n the program group was measured. A l l women on the o b s t e t r i c ward who delivered newborns were included i n the study. I n i t i a l questionnaires were used to determine r e s t r a i n t use, basic demographic information, and several c h a r a c t e r i s t i c s r e l a t i n g to r e s t r a i n t use. The questionnaires allowed estimation of r e s t r a i n t use by s e l f -reporting. In an e f f o r t to a s c e r t a i n the magnitude of any bias due to s e l f -reporting, unobtrusive observations by h o s p i t a l s t a f f were used to v e r i f y r e s t r a i n t use; however, the observer was not able to follow the subject to the automobile to determine whether the seat was used c o r r e c t l y . At s i x weeks post-partum, follow-up mail questionnaires were used to determine continued (or new) seat usage as w e l l as providing a d d i t i o n a l demographic and socio-economic information on both the c o n t r o l (pre-program) and the program groups. 3.3 Sample Si z e P r i o r to t h i s study a v a r i e t y of reports 5» 33-37 i n d i c a t e d low rates f o r use of i n f a n t r e s t r a i n t s , t y p i c a l l y rates of 20% or l e s s . A n t i c i p a t i n g s i m i l a r use rates f o r pre-program groups i n t h i s study and wanting to reach s t a t i s t i c a l s i g n i f i c a n c e f o r , say, 15% use pre-program versus 25% use among mothers i n a h o s p i t a l program, about 120 mothers were needed f o r each group (pre-program and program) i n each h o s p i t a l . In f a c t , when comparing usage 29 between two groups, each of s i z e 120, a chi-square t e s t would conclude that there i s a s i g n i f i c a n t difference (p-value about .05 or less) f o r a v a r i e t y of proportions d i f f e r i n g by about .10 (10%) or more (examples, Appendix I I ) . In hindsight, i n f a n t r e s t r a i n t use rates i n greater Vancouver appear to be high, t y p i c a l l y 45% to 90%, depending on l o c a l e and on whether use i s measured by mother's s e l f - r e p o r t i n g or by nurse's observations. I f , f o r example, two populations have use rates of 40% versus 60%, then samples of s i z e 120 from each population have p o w e r 6 1 - 6 3 greater than 90% f o r detecting d i f f e r e n c e i n a one-sided t e s t at l e v e l .05; or, comparing popula-tions with use rates of 80% versus 90%, the same s i z e samples have power greater than 70% i n a one-sided l e v e l .05 t e s t . Although the groups were la r g e r than the needed s i z e of 120 for s e l f - r e p o r t e d r e s t r a i n t use, the data recorded groups smaller than the needed s i z e f o r observed r e s t r a i n t use, and as a r e s u l t the power f o r detecting observed d i f f e r e n c e i s l e s s than a n t i c i p a t e d . For 155 subjects (as at Surrey), evenly divided i n t o two groups with observed r e s t r a i n t use rates of 43% versus 63%, the power f o r detecting t h i s d i f f e r e n c e ( i n a one-sided t e s t at l e v e l .05) would be 80%. When the groups are unevenly s p l i t (eg. 91 vs. 64 at Surrey) the power would be s l i g h t l y l e s s and the exact power determination i s complex.-'12 3.4 Questionnaire The i n i t i a l questionnaire (Appendix I I I , i ) was intended to c o l l e c t basic demographic information on the subject (e.g. age, marital s t a t u s ) , and to determine intended r e s t r a i n t use as w e l l as c e r t a i n c h a r a c t e r i s t i c s associated with i n f a n t r e s t r a i n t use (e.g. adult seat b e l t use, smoking behavior). Several references on questionnaire d e s i g n 6 4 - 6 7 suggested a simple one page format f o r best response. The i n i t i a l questionnaire f o r the program group had an a d d i t i o n a l question on viewing the f i l m (Appendix I I I , 30 i i ) . A cover l e t t e r (Appendix I I I , i i i ) on h o s p i t a l stationery was added a f t e r the questionnaire was p i l o t e d (see below). The follow-up questionnaire (Appendix I I I , iv) was mailed at s i x weeks post-partum. I t was intended to gather information on r e s t r a i n t use, as well as a d d i t i o n a l demographic and socio-economic information. I t was also one page i n length, accompanied by a cover l e t t e r on Vancouver Health Department stationery (Appendix I I I , v ) . To encourage a greater response, i t was p r i n t e d on yellow p a p e r . 6 5 Questions concerned with socio-demographic information were modelled a f t e r those contained i n the Canada census form to allow easy comparison of r e s u l t s . The procedure followed f o r the mail questionnaire was adapted from the T o t a l Design Method by D i l l m a n . 6 4 A reminder was sent one week a f t e r the questionnaire (Appendix I I I , v i ) . A follow-up l e t t e r (Appendix I I I , v i i ) and questionnaire were sent two weeks l a t e r to non-responders. A stamped, addressed envelope was included with each questionnaire mailing. The study protocol was submitted f o r agency consent to appropriate committees at each p a r t i c i p a t i n g h o s p i t a l . O v e r a l l approval of the design was obtained from the U n i v e r s i t y of B r i t i s h Columbia Behavioural Sciences Screening Committee f o r Research and Other Studies Involving Human Subjects (Appendix IV). 3.5 Program I n i t i a t i o n As the major o b s t e t r i c a l centre f o r the Greater Vancouver area, i t was f e l t that the S a l v a t i o n Army Grace H o s p i t a l s i t e would be i d e a l to i n i t i a t e the program. The pre-program period was to l a s t the month of October (1982), with the program beginning on November 1. Due to administrative 31 problems, however, t h i s timetable was not achieved. The pre-program period began two weeks l a t e , and the schedule was a l t e r e d to begin the program on November 15. The response rate to the i n i t i a l questionnaire f o r the pre-program group was 40 percent, and declined to 20 percent i n the f i r s t month of the program. E f f o r t s to increase the response rate r e s u l t e d i n only a s l i g h t increase. Administrative problems associated with the recent opening of the h o s p i t a l were f e l t to have adversely a f f e c t e d the study. I t was decided to consider t h i s experience as a p i l o t study, since the low response rate would preclude any meaningful data a n a l y s i s . Several modifications of the study methodology resulted, i n c l u d i n g abandonment of a protocol to telephone non-responders (due to lack of resources). I t should also be noted that although r e s t r a i n t r e n t a l programs provide seats at the lowest po s s i b l e cost, i t was not p o s s i b l e to set up such a program due to the large number of b i r t h s at the h o s p i t a l . Three community h o s p i t a l s , which had expressed i n t e r e s t i n e s t a b l i s h i n g the i n - h o s p i t a l program, were s o l i c i t e d to p a r t i c i p a t e i n the evaluation. Lions Gate H o s p i t a l (annual b i r t h s : 1,550) and Surrey Memorial Hospital (annual b i r t h s : 2,250) agreed to p a r t i c i p a t e . Neither f a c i l i t y had previously promoted i n f a n t r e s t r a i n t s p r i o r to the introduction of the program. 3.6 Program Procedure One s t a f f member at each h o s p i t a l assumed r e s p o n s i b i l i t y f o r coordinating the program. Each s i t e consisted of a s i n g l e post-partum ward, compared to the f i v e large u n i t s at the Grace H o s p i t a l . A cover l e t t e r (Figure 3.4.3) on h o s p i t a l stationery was designed f o r the i n i t i a l questionnaire. Each patient received the l e t t e r / q u e s t i o n n a i r e on her second day on the ward, separate from other material. D i s t r i b u t i o n was handled by only two s t a f f members at a common d a i l y time. Patients returned completed questionnaires to the ward desk, and upon discharge, whenever po s s i b l e , were asked i f they had completed questionnaires. An a s s i s t a n t i n v e s t i g a t o r v i s i t e d the ward once weekly (on a randomly chosen day each week) to c o l l e c t questionnaires from the patients, and to t r y to as c e r t a i n any reason(s) f o r non-response. Whenever po s s i b l e , ward s t a f f recorded observations of r e s t r a i n t use when a mother and i n f a n t l e f t the h o s p i t a l . At the conclusion of the pre-program period, i n - s e r v i c e sessions were held f o r the ward s t a f f to inform them of the educational program and the hazards of in f a n t s t r a v e l l i n g unrestrained i n cars. During the program period, an educational package was d i s t r i b u t e d to each patient on her day of admission to the post-partum ward. The procedure f o r questionnaire d i s t r i b u t i o n and c o l l e c t i o n was the same as during the pre-program period. At Surrey Memorial Ho s p i t a l the f i l m was screened d a i l y f o r the program group i n a pa t i e n t lounge on the post-partum ward. Announcements of the screening time were posted on the ward. S t a f f at Lions Gate Hospital were unable to arrange f o r d a i l y f i l m screenings, therefore the program at that s i t e included only the educational package and the sale of i n f a n t r e s t r a i n t s . In order to obtain 120 subjects i n each group ( i n each hospit a l ) questionnaires were d i s t r i b u t e d f o r a period of four to s i x weeks. The study was implemented at the two h o s p i t a l s during the spring of 1983. The s p e c i f i c dates f o r each h o s p i t a l pre-program and program periods are outl i n e d i n Figure 3.6.1 D i s t r i b u t i o n of the program questionnaire at Lions Gate H o s p i t a l was stopped prematurely due to an administrative error, therefore an ad d i t i o n a l d i s t r i b u t i o n period was added. 33 F i g . 3.6.1: I n i t i a l Questionnaire D i s t r i b u t i o n Periods HOSPITAL Pre-Program Period Program Period LIONS GATE March 12 - A p r i l 24 May 2-29 Jul y 25-August 12 SURREY May 24 - June 27 July 4 - August 12 34 3 .7 S t a t i s t i c a l Analysis In t h i s study the outcomes, s e l f - r e p o r t e d or observed use of infant r e s t r a i n t s , were simple dichotomies (yes or no). Most demographic or pr e d i c t o r v a r i a b l e s (from e i t h e r questionnaire) also were categoric - e.g., mother's seat b e l t use; smoking; marital status; language. Also broad i n t e r v a l s categorized mother's education and family income. Categoric data were cross-tabulated i n 2x2 or larger contingency tables. Lions Gate and Surrey Hospitals were compared demographically; and pre-program versus program groups i n each h o s p i t a l were compared. Also patterns of missing data were examined. Chi-square s t a t i s t i c s were c a l c u l a t e d to t e s t s i g n i f i c a n c e of pre-program versus program differences with respect to outcomes ( c h i l d r e s t r a i n t use) and pos s i b l e confounding f a c t o r s . Also l o g - l i n e a r analysis of three-dimensional contingency tables was used to examine r e l a t i o n s h i p s among outcome, mother's education, and family income. Ages of mothers could be analyzed as continuous variables; and various group means were compared using two-sample t - t e s t s . 35 Chapter 4: Results 4.1 Questionnaire Response Rates O v e r a l l a high response rate to the questionnaires was obtained. The response rates were comparable between the pre-program and program groups, as well as between h o s p i t a l s . At Lions Gate Ho s p i t a l i n the pre-program period, the i n i t i a l questionnaire was returned by 128 of 170 women to whom i t was d i s t r i b u t e d (response rate of 75.3%). In the program period, the i n i t i a l questionnaire was returned by 129 of 174 women who received i t (74.1%). At Surrey Memorial H o s p i t a l i n the pre-program period, the i n i t i a l questionnaire was returned by 151 of 200 women to whom i t was d i s t r i b u t e d (response rate of 75.5%). In the program period, the i n i t i a l questionnaire was returned by 146 of 200 women who received i t (73.0%). The follow-up questionnaire was mailed only to those women who returned the i n i t i a l questionnaire. At Lions Gate Ho s p i t a l i n the pre-program period, the follow-up questionnaire was returned by 115 of 128 women to whom i t was sent (response rate of 89.8%). In the program period, t h i s questionnaire was returned by 119 of 129 women to whom i t was mailed (92 .2%). At Surrey Memorial H o s p i t a l i n the pre-program period, the follow-up questionnaire was returned by 131 of 151 women to whom i t was sent (86.8%). In the program period, t h i s questionnaire was returned by 129 of 146 women to whom i t was mailed (88.4%). Questionnaire d i s t r i b u t i o n and response are i l l u s t r a t e d i n Figure 4.1.1. Figure 4.1.1: Questionnaire D i s t r i b u t i o n and Response -t o t a l d i s t r i b u t e d -< 1 st ?'aire returned• follow-up-wmmmmmmm Lions Gate Hospital 170 128 115 Surrey Memorial Hospital Pre-program m 131 151 200 Program mmmmmmmmmmmmmmmmm 174 129 119 m 129 146 200 Table I : Summary of Item Omissions Among I n i t i a l Questionnaire Responses (n = number of respondents i n group) Information Area* Lions Gate Surrey T o t a l Pre-program Program Pre-program Program (n = 128) (n = 129) (n = 151) (n = 146) (n = 554) Mother's Age 3 8 12 9 32 M a r i t a l Status 0 0 0 0 0 Sex of c h i l d 1 0 0 1 2 Mother's f i r s t c h i l d 1 0 0 0 1 Car Access 0 0 0 0 0 Restraint Use 7 1 9 9 26 (s e l f - r e p o r t ) Seat B e l t Use 0 0 0 0 0 Smoking Behaviour 4 1 2 1 8 Viewing of f i l m - - - 2 2 *Refer to i n i t i a l questionnaire. 38 4.2 Missing Data I n i t i a l questionnaires were l a r g e l y complete (see Table I ) . Among nine information areas, age was the s i n g l e item most often omitted (32/554 = 5.8%). Three of the nine areas had no missing data among 554 respondents (combining pre-program and program groups i n both h o s p i t a l s ) . The amount of missing data on the follow-up questionnaire was consider-ably more than that encountered on the i n i t i a l questionnaire, e s p e c i a l l y with respect to education and family income information (see Table I I ) . There were 494 respondents to the follow-up questionnaire (combining pre-program and program groups i n both h o s p i t a l s ) . Observation by h o s p i t a l s t a f f of r e s t r a i n t use upon discharge was recorded f o r 304 of 554 subjects who had completed i n i t i a l questionnaires. This represents an observation rate of 54.9% (see Table I I I ) . 4.3 Comparability of H o s p i t a l Subject Populations The pre-program subject populations of Lions Gate H o s p i t a l and Surrey Memorial H o s p i t a l were comparable with respect to the following v a r i a b l e s : marital status, f i r s t c h i l d , seat b e l t use, family income, and language; but s t a t i s t i c a l l y s i g n i f i c a n t differences between the h o s p i t a l s were noted with respect to age (p < .001), education (p < .001), and smoking behaviour (p < .05). As a group, subjects at Lions Gate H o s p i t a l were older, better educated, and smoked les s than subjects at Surrey Memorial H o s p i t a l . The c a l c u l a t i o n s f o r these comparisons are summarized i n Appendix V. Since these l a t t e r three v a r i a b l es are a l l r e l a t e d to use of i n f a n t car r e s t r a i n t s ( i n previous studies and i n t h i s study - see below), comparisons between pre-program and program groups must be within each h o s p i t a l Table I I : Summary of Item Omissions Among Follow-up Questionnaire Responses (n = number of respondents i n group) Information Area* Lions Gate Surrey T o t a l Pre-program (n = 115) Program (n = 119) Pre-program (n = 131) Program (n = 129) (n = 494) Have r e s t r a i n t Often use Education Family income Smoking behaviour Language 15 19 51 86 14 12 10 9 45 74 7 7 21 24 38 89 22 21 17 21 32 87 18 17 63 73 166 336 61 57 *Refer to follow-up questionnaire. Table I I I : Summary of Missing Observations of Restraint Use (n = number of subjects i n group) Lions Gate Surrey T o t a l Pre-program (n = 128) 46 Program (n = 129) 62 Pre-program (n = 151) 60 Program (n = 146) 82 (n = 554) 250 40 separately. Analysis of combined data would otherwise confound h o s p i t a l d i f f e r e n c e and program e f f e c t s . 4.4 Comparability of Groups Within Each Hospital At both h o s p i t a l s the pre-program and program groups were comparable with respect to a l l background v a r i a b l e s : age, marital status, mother's f i r s t c h i l d , seat b e l t use, smoking behaviour, education, family income, and language. The tables and s t a t i s t i c s f o r these comparisons are contained i n Appendix VI. 4.5 Restraint Use: Self-Report No s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e was noted between the pre-program and program groups within each h o s p i t a l with respect to s e l f - r e p o r t of r e s t r a i n t use (see Tables IVa, IVb). 4.6 Restraint Use: Observation Contrary to s e l f - r e p o r t , the observed use of r e s t r a i n t s at Surrey was s i g n i f i c a n t l y greater f o r the program group (see Table Vb). At Lions Gate, where observed use was more consistent with very high s e l f - r e p o r t e d use (see Table Va), the observed use of r e s t r a i n t s d i d not d i f f e r s i g n i f i c a n t l y f o r pre-program and program groups. Figure 4.6.1 g r a p h i c a l l y represents the comparisons of pre-program and program observed r e s t r a i n t use within and between h o s p i t a l s . 4.7 Inconsistency Between Self-Reported and Observed Restraint Use Determination of bias i n s e l f - r e p o r t i n g of r e s t r a i n t use was (necessarily) l i m i t e d to those respondents who also were observed. A difference i n pattern emerged between the two h o s p i t a l s : the bias at Surrey was much greater than that at Lions Gate. 41 Table IVa: Self-Report of Restraint Use; Lions Gate Pre-program Program Restraint Use (s e l f - r e p o r t ) X 2 = 1.53 No Yes 14 107 DF = 1 p > .2 (11.6%) (88.4%) 121 (100.0%) 9 (7.0%) 23 119 (93.0%) 226 128 (100.0%) 249 Table IVb: Self-Report of Restraint Use; Surrey Pre-program Program Restraint Use ( s e l f - r e p o r t ) No 19 (13.4%) 27 (19.7%) 46 Yes 123 (86.6%) 110 (80.3%) 233 142 (100.0%) 137 (100.0%) 279 X 2 = 2.05 DF = 1 p > .15 42 At Lions Gate, observations were made f o r 142 of 249 subjects (57%). Self-reported r e s t r a i n t use was 129 of 142 subjects (90.8%); while observed r e s t r a i n t use was 127 of 142 subjects (89.4%) (Table V i a ) . An unexpected f i n d i n g showed that 10 subjects who reported that they did not intend to use a r e s t r a i n t , were i n f a c t observed to be using one upon discharge. At Surrey, observations were made f o r 146 of 279 subjects (52%). Self - r e p o r t e d r e s t r a i n t use was 120 of 146 subjects (82.2%); while observed r e s t r a i n t use was only 77 of 146 subjects (52.7%) (Table VIb). Observed subjects were compared to subjects f o r whom no observation was made. No s t a t i s t i c a l l y s i g n i f i c a n t differences were found with respect to the following v a r i a b l e s : age, seat b e l t use, smoking behaviour, education, family income, and language. The c a l c u l a t i o n s f o r these comparisons are contained i n Appendix VII. 4.8 Comparability of Consistent Subjects with Subjects Observed  to be Not Consistent with Respect to S e l f - r e p o r t A comparison was made between subjects whose s e l f - r e p o r t of r e s t r a i n t use was consistent with the observation of t h e i r r e s t r a i n t use and subjects whose s e l f - r e p o r t of r e s t r a i n t use was not consistent with the observation. No di f f e r e n c e was noted between the two subject populations with respect to seat b e l t use, family income, smoking behaviour, or language. S t a t i s t i c a l l y s i g n i f i c a n t d ifferences were noted, however, with respect to the following v a r i a b l e s : mother's age (p<.02), and education (p<.05). Mothers whose s e l f - r e p o r t i n g was u n r e l i a b l e tended to be younger and less w e l l educated. The c a l c u l a t i o n s f o r these comparisons are contained i n Appendix VII. 43 Table Va: Observed Restraint Use: Lions Gate Pre-program Program Res t r a i n t Use No 10 (12.2%) 6 (9.0%) 16 (observed) Yes 72 (87.8%) 61 (91.0%) 133 82 (100.0%) 67 (100.0%) 149 X 2 = .40 DF = 1 p > .5 Table Vb: Observed Restraint Use: Surrey Pre-program Program Restraint Use No 52 (57.1%) 24 (37.5%) 76 (observed) Yes 39 (42.9%) 40 (62.5%) 79 91 (100.0%) 64 (100.0%) 155 X 2 = 5.81 DF = 1 p < .02 Table V i a : Inconsistency i n Self-Reporting: Lions Gate Observation of Restraint Use Yes No Self-Report Yes 117 12 129 (90.8%) of r e s t r a i n t use No 10 3 13 (9.2%) 127(89.4%) 15(10.6%) 142 Table VIb: Inconsistency i n Self-Reporting: Surrey Observation of Restraint Use Yes No Se l f - r e p o r t Yes 75 45 120 (82.2%) of r e s t r a i n t use No 2 24 26 (17.8%) 77(52.7%) 69(47.3%) 146 44 4.9 Variables Associated with Self-Report of Restraint Use A number of previous studies have reported s i g n i f i c a n t associations of several v a r i ables with s e l f - r e p o r t e d r e s t r a i n t u s e . 5 ' 6 ' 4 ^ Although i n t h i s study s e l f - r e p o r t e d r e s t r a i n t use was found to be u n r e l i a b l e (see section 4.10, discussion of 3-way t a b l e ) , variables associated with s e l f - r e p o r t w i l l be presented to allow comparison with these studies and also further discussion i n the next chapter. S e l f - r e p o r t of r e s t r a i n t use was cross-tabulated with c e r t a i n variables to determine t h e i r s t a t i s t i c a l a s sociations. Table VII i n d i c a t e s the p-values f o r these cross-tabulations and f o r a t - t e s t to compare ages f o r the subject group o v e r a l l and f o r each h o s p i t a l separately. Appendix IX contains the cross-tabulations and the s t a t i s t i c a l d e t a i l s . 4.10 Variables Associated with Observed Restraint Use Observation of r e s t r a i n t use was s i m i l a r l y cross-tabulated with c e r t a i n v a r i a b l e s to determine t h e i r p r e d i c t i v e value. Table VIII indicates the p-values f o r these cross tabulations and t - t e s t s f o r the subject group over-a l l and f o r each i n d i v i d u a l h o s p i t a l . Appendix X contains the s t a t i s t i c a l d e t a i l s . I t can be noted i n Table VIII that several v a r i a b l e s (eg. m a r i t a l status, education, smoking behaviour, age) are s i g n i f i c a n t l y associated with observed r e s t r a i n t use i n the combined data but are not s i g n i f i c a n t f o r e i t h e r h o s p i t a l separately; and s i m i l a r l y f o r Table VII. Also, i n comparing Table VII and VIII, note that s e l f - r e p o r t and observed use ( i n the combined data) are associated with quite d i f f e r e n t v a r i a b l e s . A d e t a i l e d discussion of these findings follows i n Chapter 5. 45 Table VII: P-Values f o r Chi-Square Testing of Variables Possibly Associated with Self-Report of Restraint Use V a r i a b l e Combined Lions Gate Surrey M a r i t a l Status .01 .01 Seat B e l t Use < .01 .01 Education .29 Family Income < .001 .27 Smoking Behaviour < .001 .03 Language < .001 < .001 .18 F i r s t C h i l d < .01 .06 .01 .08 85 .23 < .01 .001 < .001 Mother's Age Mean dif f e r e n c e (users older) .03 1 .3 years .02 +.91 2.5 years 0.1 years p-value f o r t - t e s t 46 Table V I I I : P-Values f o r Chl-Square T e s t i n g of Variables Possibly Associated with Observed Restraint Use Combined Lions Gate Surrey V a r i a b l e M a r i t a l Status .03 .31 .14 F i r s t C h i l d .13 .52 .03 Seat B e l t Use .07 .17 .03 Education < .01 .93 .03 Family Income .12 .23 .19 Smoking Behaviour < .01 .18 .15 Language .07 .44 < .06 Mother's Age +< .001 +.10 +.01 Mean dif f e r e n c e 2.6 years 2.1 years 1.8 years (users older) p-value f o r t - t e s t 47 The r e l a t i o n s h i p s among family income, education, and r e s t r a i n t use were furth e r i n v e s t i g a t e d using l o g - l i n e a r analysis of 3-way contingency t a b l e s . For the l i m i t e d number of observed mothers who also reported both education and family income, the 3-way modelling shows s i g n i f i c a n t i n t e r -action between income and education. And the model which includes the income-education i n t e r a c t i o n plus i n t e r a c t i o n between education and observed use gives quite a s a t i s f a c t o r y f i t to the data; that i s , observed use i s co n d i t i o n a l l y independent of family income at each education l e v e l . (Education i s more s i g n i f i c a n t than reported family income as a pr e d i c t o r of observation of use.) S t a t i s t i c a l d e t a i l s , c a l c u l a t e d with the BMDP4F program, are i n Appendix XI. For the 3-way table with s e l f - r e p o r t e d r e s t r a i n t use, family income, and education, only the saturated model (inc l u d i n g a l l 2-way in t e r a c t i o n s plus the 3-way int e r a c t i o n ) f i t s the data (gives a p-value above .05). This r e s u l t suggests that s e l f - r e p o r t i s random, i n the sense that no combination of information about family income and mother's education has s i g n i f i c a n t p r e d i c t i v e value. S t a t i s t i c a l d e t a i l s , again c a l c u l a t e d with the BMDP4F program, are i n Appendix XII. 48 Chapter 5: Discussion 5.1 Introduction This chapter compares the r e s u l t s presented above with those a n t i c i -pated p r i o r to the study and with the findings of previously reported studies. Any differences from a n t i c i p a t e d or previous findings are i n t e r -preted and conclusions are drawn. F i n a l l y , the implications of t h i s study i n planning s i m i l a r i n f a n t r e s t r a i n t programs are considered. 5.2 Questionnaire Response and Completion O v e r a l l , f o r the i n i t i a l questionnaire, a high response rate was obtained (range 73.0% to 73.5%) with very l i t t l e missing data (which was not consequential to the f i n a l a n a l y s i s ) . The a s s i s t a n t i n v e s t i g a t o r s en-countered only two i n d i v i d u a l s who refused to complete t h i s questionnaire. The response rate f o r the follow-up questionnaire was exceedingly high f o r a mail questionnaire (range: 86.8% to 92.2%) given that i n e v i t a b l y some questionnaires w i l l be l o s t i n the p o s t a l service. M a i l surveys with response rates of 30% to 50% are considered s a t i s f a c t o r y , while a response rate of 70% i s considered e x c e p t i o n a l . 6 5 The high response rates achieved were l i k e l y due to the f a c t that these mothers were motivated by i n t e r e s t i n t h e i r babies' welfare and were a captive audience i n h o s p i t a l and a l s o l a t e r at home. The organization and motivation of the ward s t a f f ensured questionnaire d i s t r i b u t i o n and an i n t e r e s t i n completed questionnaire c o l l e c t i o n . There are several p o s s i b l e reasons f o r the low response rate at Grace Hospital during the p i l o t study period. At the time of the study, the h o s p i t a l was new and organizational systems had not been f u l l y worked out. Due to a lack of experience, the i n v e s t i g a t o r had not c l e a r l y defined l i n e s of r e s p o n s i b i l i t y i n carrying out the study, and as a r e s u l t the s t a f f were 49 not aware of t h e i r involvement. Also mothers at Grace Hospital include a l a r g e r percentage of non-English speakers than e i t h e r Lions Gate H o s p i t a l or Surrey. The experience encountered i n t h i s study c l e a r l y demonstrates the usefulness of a p i l o t study. No means were a v a i l a b l e to contact non-responders to the i n i t i a l ques-t i o n n a i r e . I t i s u n l i k e l y that as a group non-responders would have a higher rate of r e s t r a i n t use than those who responded; rather that r e s t r a i n t use f o r non-responders would be the same or lower than the subject population. The information supplied on the follow-up questionnaire was considerab-l y more incomplete than that obtained from the i n i t i a l questionnaire. Mis-sing data f o r four information areas (possession of a r e s t r a i n t , frequency of use, smoking behaviour, and language) ranged between 11.5% to 14.8%; how-ever, mother's education was incomplete i n 33.6% of follow-up question-naires, and family income was incomplete f o r 60.6%. The large amount of missing data f o r these two key v a r i a b l e s greatly r e s t r i c t e d the analysis ( d e t a i l s below). Despite the assurance of c o n f i d e n t i a l i t y , subjects were reluctant to answer questions concerning t h e i r education and family income. Many questionnaires had notations that the information requested was p r i v a t e and d i d not r e l a t e to i n f a n t r e s t r a i n t use. The problem of missing data i n areas considered " c o n f i d e n t i a l " by ques-tionna i r e respondents has been reported i n the l i t e r a t u r e . 6 4 ' 6 7 Family income and education have been i d e n t i f i e d as p o s i t i v e l y associated with seat b e l t use and i n f a n t r e s t r a i n t s ; 6 ' 4 1 ' 6 8 ' 6 8 ' 7 0 but i t i s unclear from these reports whether the data sets, upon which these conclusions were based, were complete. In view of the findings of t h i s study, the r e l i a b i l -i t y of s e l f - r e p o r t e d data i n c o n f i d e n t i a l areas may be questionable even when the data i s v i r t u a l l y complete. 50 5.3 C h a r a c t e r i s t i c s of the Hospital Subject Populations A comparison of the pre-program groups at each h o s p i t a l revealed that subjects at Lions Gate Ho s p i t a l were s l i g h t l y older, better educated, less l i k e l y to smoke than the mothers at Surrey Memorial H o s p i t a l . These charac-t e r i s t i c s have been reported previously (and again here) to be associated with higher rates of use of seat b e l t s and i n f a n t r e s t r a i n t s . Obviously the differences between Lions Gate and Surrey with respect to these c h a r a c t e r i s -t i c s requires that the program be evaluated separately i n each h o s p i t a l . I t i s important to note the differences between these two suburban community h o s p i t a l s . I t should never be assumed that community ho s p i t a l s serve homogeneous populations i n suburban areas, and that programs w i l l have s i m i l a r r e s u l t s . A f u r t h e r comparison between the pre-program and program groups within each h o s p i t a l separately found them to be s i m i l a r with respect to a l l key v a r i a b l e s . 5.4 Observed Restraint Use and Program Evaluation At Lions Gate, 87.8% of observed subjects used r e s t r a i n t s i n the pre-program period, while 91.0% of observed subjects used r e s t r a i n t s i n the program period. No s t a t i s t i c a l l y s i g n i f i c a n t difference was noted; and o v e r a l l , 89.3% of observed subjects used i n f a n t r e s t r a i n t s . The observation rate at Lions Gate was 64% of subjects i n the pre-program p e r i o d and 52% of subjects i n the program period. This decline i n the observation rate was most l i k e l y a r e s u l t of f a l l i n g i n t e r e s t and fatigue on the part of the s t a f f . Although fewer observations were made i n the program period, the rate of use was maintained. 51 Observed subjects were compared to those f o r whom no observation of r e s t r a i n t use was made. The two groups were s i m i l a r with respect to a l l of the key v a r i a b l e s : age, seat b e l t use, smoking behaviour, education, family income, and language. I t would, therefore, seem to be a reasonable assump-t i o n to expect r e s t r a i n t use i n the non-observed group to be s i m i l a r to that of the observed group, and that no systematic observer bias was encountered. In an e f f o r t to evaluate the program at Lions Gate under a "worst case" assumption, non-responders to the i n i t i a l questionnaire may be considered to be non-users, and the use rate among unobserved subjects may be considered to be the same as observed subjects. In the pre-program period, there are 128 responders (of 170 patients) and the observed use rate was 87.8%. Under the "worst case" assumption t h i s would y i e l d a use rate of 66.1% (128 x .878/170). In the program period, there were 129 responders (of 174 patients) and an observed use rate of 91.0%. In the program the "worst case" assumption y i e l d s a use rate of 67.5% (129 x .91/174). These rates are higher than those a n t i c i p a t e d i n view of the B.C. Research s u r v e y , 3 8 although they are comparable to the highest r e s t r a i n t usage rate at h o s p i t a l discharge (67%) reported i n a previous study of a hospital-based educational i n t e r v e n t i o n . 4 0 The experimental group of t h i s l a t t e r study, however, involved only 15 women. The s i t u a t i o n encountered at Surrey Memorial Ho s p i t a l was markedly d i f -f e r e n t . In the pre-program period 42.9% of observed subjects used r e s t r a i n t s , while i n the program period 62.5% of observed subjects used r e s t r a i n t s . A s t a t i s t i c a l l y s i g n i f i c a n t difference was noted between the two periods (p<.02). Once again the observation rate declined from 60% of subjects i n the pre-program peri o d to 44% of subjects i n the program period. Applying 52 the "worst case" assumption (noted above) to the population at Surrey, r e s t r a i n t use f o r the pre-program period would be 32.4% (151 x .429/200), and f o r the program period 45.% (146 x .625/200). The differ e n c e noted i s s t a t i s t i c a l l y s i g n i f i c a n t (p<.01). The rates derived from the "worst case" assumption at Surrey are some-what lower than those a n t i c i p a t e d i n view of the B.C. Research s u r v e y . 3 8 I t i s quite l i k e l y that some of the nonresponders would have used r e s t r a i n t s upon discharge thereby increasing the o v e r a l l usage rate; nevertheless, r e s t r a i n t usage at Surrey increased s i g n i f i c a n t l y f o r the program group but was much lower than that observed at Lions Gate. The rates e l i c i t e d under the "worst case" assumption at both hospit a l s are comparable to those previously reported i n roadside observational sur-veys (range 11% to 5 3 % ) . 1 1 ' 3 3 ~ 3 5 ' 3 8 I t should be noted, however, that the measurement used i n t h i s study was a s i n g l e observation of r e s t r a i n t use at h o s p i t a l discharge. From the r e s u l t s i t appears that i n h o s p i t a l s where currently only a minority of mothers use i n f a n t r e s t r a i n t s , t h i s program may s i g n i f i c a n t l y increase usage. 5.5 V a l i d i t y of Self-Report With respect to automobile safety b e l t s , s e l f - r e p o r t e d use generally overestimates ac t u a l observed use.25,51,55-57 studies that have com-pared observed and claimed use of i n f a n t / c h i l d r e s t r a i n t s have reported observed use 33% to 66% of claimed u s e . 5 1 ' 5 7 ' 5 8 These l a t t e r r e s u l t s , however, are questionable since i n each study the comparability of the observed group and the s e l f - r e p o r t i n g group was not determined. Although several previous studies have measured s e l f - r e p o r t e d r e s t r a i n t u s e , 5 ' 4 2 ' 4 9 ' 5 0 ' 5 3 i t would appear that s e l f - r e p o r t i s not a r e l i a b l e outcome measure and the r e s u l t s of these studies may be suspect. Recogniz-ing t h i s f a c t , several i n v e s t i g a t o r s have measured observed r e s t r a i n t u s e . 3 4 ' 4 0 ' 5 4 In an attempt to v a l i d a t e s e l f - r e p o r t , i t would seem obvious to measure s e l f - r e p o r t and observation on the same i n d i v i d u a l s ; however, the present study appears to be the f i r s t report comparing s e l f - r e p o r t e d and observed r e s t r a i n t use on the same i n d i v i d u a l s . At Lions Gate, o v e r a l l s e l f - r e p o r t e d use was 90.8% and observed use was 89.4%. Although these rates were almost i d e n t i c a l , observed users included 10 subjects who reported that they would not be using r e s t r a i n t s . There were no obvious sources of er r o r noted f o r these subjects (eg. coding), although i t i s po s s i b l e that the observation was recorded i n c o r r e c t l y . The i n d i v i d u a l s may have received r e s t r a i n t s p r i o r to discharge (but a f t e r com-p l e t i n g the i n i t i a l questionnaire) or perhaps had been influenced by the high r e s t r a i n t use at the h o s p i t a l (peer pressure). U t i l i z i n g peer pressure as a strategy i n promoting r e s t r a i n t s may be an e f f e c t i v e a d d i t i o n to other e f f o r t s although i t has not been previously described i n the l i t e r a t u r e . Of the 129 subjects who claimed they would use a r e s t r a i n t upon discharge, 117 or 90.7% were i n f a c t observed to be using them. At Surrey, o v e r a l l s e l f - r e p o r t e d r e s t r a i n t use was 82.8%; however, observed use was only 52.7%. Of the 120 subjects who claimed they would use a r e s t r a i n t upon discharge, 75 or 62.5% were i n f a c t observed using them. This i s i n marked contrast to the s i t u a t i o n noted at Lions Gate. I t was not unexpected to show a bias toward s e l f - r e p o r t e d r e s t r a i n t use. Subjects w i l l tend to answer p o s i t i v e l y to t h i s question since they 54 r e a l i z e that t h i s i s the "correct" response. A comparison was made between subjects whose s e l f - r e p o r t of r e s t r a i n t use was consistent with observed use and those whose s e l f - r e p o r t was not consistent. S t a t i s t i c a l l y s i g n i f i c a n t differences were noted with respect to two v a r i a b l e s , i n that subjects whose s e l f - r e p o r t i n g was u n r e l i a b l e tended to be younger and les s w e l l educated. Also these " u n r e l i a b l e " subjects tended more to omit information on education and family income from t h e i r questionnaires. 5.6 Variables Associated with Restraint Use Previous studies on seat b e l t use have i n d i c a t e d p o s i t i v e associations with a g e , 2 0 ' 6 8 ' 7 0 e d u c a t i o n , 6 8 - 7 1 and i n c o m e . 6 8 ' 6 9 Married people are more l i k e l y to be seat b e l t users than s i n g l e p e o p l e , 6 8 and non-users are more l i k e l y to be smokers. 6 8 With respect to use of i n f a n t r e s t r a i n t s , p o s i t i v e associations have been reported f o r parents' age, 5 e d u c a t i o n , 6 ' 4 1 and income. 6' 4 1 M a r i t a l status (married) was noted to be associated with r e s t r a i n t use, 5 as well as b i r t h order ( f i r s t c h i l d ) , and parents' seat b e l t use was also a strong determinant of r e s t r a i n t u s e . 5 ' 6 These associations were a l l based on s e l f - r e p o r t of r e s t r a i n t use. In the present study, s e l f - r e p o r t e d and observed use ( i n the combined data) are associated with quite d i f f e r e n t v a r i a b l e s . In p a r t i c u l a r , family income i s very s i g n i f i c a n t when cross-tabulated with s e l f - r e p o r t of r e s t r a i n t use, but i s not at a l l s i g n i f i c a n t l y associated with a c t u a l observed r e s t r a i n t use. Conversely, education i s very s i g n i f i c a n t when cross-tabulated with observed use, but i s not associated with s e l f - r e p o r t of use. This f i n d i n g i s pos s i b l e because, as reported above, there i s substan-t i a l inconsistency between s e l f - r e p o r t e d and act u a l , observed use of r e s t r a i n t s . Also r e c a l l that many respondents omitted income or education from the follow-up questionnaire. 55 Several v a r i a b l e s were s i g n i f i c a n t l y associated with r e s t r a i n t use (both s e l f - r e p o r t e d and observed) i n the combined data but not f o r e i t h e r h o s p i t a l separately. This i s a r e s u l t of the sample s i z e being too small when considered separately, but s u f f i c i e n t l y large when combined. For observed r e s t r a i n t use, p o s i t i v e associations were found with m a r i t a l status (married), education, and age. Also observed r e s t r a i n t use was negatively associated with smoking behaviour. Compared to non-users, mothers who used i n f a n t r e s t r a i n t s tended to be s l i g h t l y older, better educated, married, and l e s s l i k e l y to smoke. The present study d i d not f i n d s t a t i s t i c a l l y s i g n i f i c a n t associations f o r observed r e s t r a i n t use with family income, b i r t h order, parent's seat b e l t use or parent's language, although the l a t t e r two v a r i a b l e s tended towards s i g n i f i c a n t associations (p=.07). 5.7 Summary The primary focus of the present study was to determine what increase i n r e s t r a i n t use i s associated with the i n - h o s p i t a l program. From the r e s u l t s i t appears that i n h o s p i t a l s where currently only a minority of mothers use i n f a n t r e s t r a i n t s , t h i s program may s i g n i f i c a n t l y increase us-age. When r e s t r a i n t use i s high, the program may show l i t t l e or no e f f e c t . In the course of the study i t was found that i n f a n t r e s t r a i n t use at h o s p i t a l discharge may vary s i g n i f i c a n t l y among neighbouring community hos-p i t a l s . The rates of observed r e s t r a i n t use, however, were r e l a t i v e l y high when compared to previously reported rates i n areas without r e s t r a i n t l e g i s l a t i o n . 56 Substantial inconsistency was noted between s e l f - r e p o r t e d and actual observed use of r e s t r a i n t s . This f i n d i n g may cast some doubt on the r e s u l t s of previously reported studies which used s e l f - r e p o r t as the sole outcome measure. Compared to non-users, observed r e s t r a i n t users tended to be s l i g h t l y older and better educated. They also tended to be married and were les s l i k e l y to smoke. 5.8 Planning Implications The r e s u l t s of t h i s study point to s p e c i f i c procedures to follow i f consideration i s given to implementation of a s i m i l a r program. I t appears that the program i s e f f e c t i v e when a minority of mothers are using r e s t r a i n t s , therefore the base rate of r e s t r a i n t use must f i r s t be ascertained. As s e l f - r e p o r t i s not a r e l i a b l e measure, the base determina-t i o n must be done through observation. S i m i l a r l y i f the program i s i n s t i -tuted, evaluation must be done using observation. Program implementation must be organized to ensure that s t a f f are aware of any r e s p o n s i b i l i t i e s i n i n i t i a t i n g the program, and also that i t i s coordinated with other h o s p i t a l routine. A designated coordinator would be e s s e n t i a l to organize a l l aspects of the program. Certain mothers may be more l i k e l y to be non-users (eg. teenagers, smokers) and s p e c i a l e f f o r t s may be d i r e c t e d at these target groups. E n l i s t i n g the a i d of mothers using r e s t r a i n t s at discharge i n a "peer counselling" manner might be considered. 57 References 1. S t a t i s t i c s Canada, V i t a l S t a t i s t i c s , M o r t a l i t y , Summary L i s t of Causes, V o l . I l l , Ottawa, 1981. Supply and Services, 1983. (Catalogue 84-206 Annual). 2. D i v i s i o n of V i t a l S t a t i s t i c s , M i n i s t r y of Health, V i c t o r i a , B.C., 1981. 3. Scherz, R.G. F a t a l Motor Vehicle Accidents of C h i l d Passengers from B i r t h Through 4 Years of Age i n Washington State, P e d i a t r i c s , V o l . 68, No. 4, October 1981, p. 572-575. 4. Williams, A.F. and Zador, P. I n j u r i e s to Children i n Automobiles i n Relation to Seating Location and Restraint Use. Accid. Anal & Prev., Vol. 9, 1977, p. 69-76. 5. Verreault, R., Stulginskas, J . , Keyl, P., Read, J . and Pless, I.B. Use of Automobile Seat Restraints by Children i n Two Canadian C i t i e s . 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Williams, A.F., and Wells, J.K. The Tennessee C h i l d Restraint Law i n i t s T h i r d Year. AJPH, V o l . 71, No. 2, Feb. 1981, p. 163-165. 35. Williams, A.F., and Wells, J.K. Evaluation of the Rhode Island C h i l d Restraint Law, AJPH, V o l . 71, No. 7, J u l y 1981, p. 742-743. 36. Nichols, J.L. Effectiveness and E f f i c i e n c y of Safety B e l t and C h i l d Restraint Usage Programs; The Safety P o t e n t i a l of Safety B e l t s , C h i l d Restraints, and Programs to Promote Their Use. U.S. Dept. of  Transportation, National Highway T r a f f i c Safety Administration, Washington, D.C., Jan. 1982. 37. Sanders, R.S. L e g i s l a t i v e Approach to Auto Safety i n Bergman, AB (ed.): Preventing Childhood I n j u r i e s . Report of the Twelfth Ross  Roundtable on C r i t i c a l Approaches to Common P e d i a t r i c Problems, Columbus, OH: Ross Laboratories, 1982, p. 39-43. 38. Usage of C h i l d Safety Seats i n B r i t i s h Columbia. Prepared f o r the  Insurance Corporation of B r i t i s h Columbia by B.C. Research, Vancouver, Oct. 1982. 39. Reisinger, K.S., and Williams, A.F. Evaluation of Programs Designed to Increase the P r o t e c t i o n of Infants i n Cars. P e d i a t r i c s , Vol. 62, No. 3, September 1978, p. 280-287. 40. Christopherson, E.R. and S u l l i v a n , M.A. Increasing the Protection of Newborn Infants i n Cars. P e d i a t r i c s , V o l . 70, No. 1, J u l y 1982, p. 21-25. 60 41. Eriksen, M.P. and Gielen, A.C. The A p p l i c a t i o n of Health Education P r i n c i p l e s to Automobile C h i l d Restraint Programs. Health  Education Quarterly, 10:1, Spring 1983, p. 30-55. 42. Kanthor, H.A. Car Safety f o r Infants: Effectiveness of Prenatal Counselling. P e d i a t r i c s , V o l . 59, No. 6, June 1977, p. 320-322. 43. Spaight, S.J., F i n i s o n , L . J . , Corwin, J . Use of Automobile Safety Restraints f o r Children. New England Journal of Medicine, V o l . 303, No. 25, December 18, 1980, p. 1481-82. 44. Williams, A.F., and Robertson, L.S. Observed Daytime Seat-Belt Use i n Vancouver Before and A f t e r the B r i t i s h Columbia Belt-Use Law. Canadian Journal of P u b l i c Health, V o l . 70, Sept./Oct. 1979, p. 329-332. 45. Marzoni, P. Motivating Factors i n the Use of Restraint Systems, National Analysts Inc., P h i l a d e l p h i a , Pennsylvania. Prepared f o r U.S.  Department of Transportation, National Highway T r a f f i c Safety  Administration, Washington, D.C, September 1971. 46. Seat B e l t Campaign F a i l s . P u b l i c Health Reports, V o l . 85, No. 7, J u l y 1970, p. 655. 47. Robertson, L.S., K e l l e y , A.B., O ' N e i l l , B., Wixom, C., E i s w i r t h , R.S., Haddon, W. J r . A Controlled Study of the E f f e c t of T e l e v i s i o n Messages on Safety B e l t Use. American Journal of P u b l i c Health, V o l . 64, No. 11, November 1974, p. 1071-1080. 48. Bass, L.N., and Wilson, T.R. The P e d i a t r i c i a n ' s Influence i n P r i v a t e P r a c t i c e Measured by a Controlled Seat B e l t Study. P e d i a t r i c s , V o l . 34, May, 1964, p. 700-704. 49. Scherz, R.G. Restraint Systems f o r the Prevention of Injury to Children i n Automobile Accidents. American Journal of P u b l i c Health, V o l . 66, No. 5, May 1976, p. 451-456. 50. M i l l e r , J.R., and Pless, I.B. C h i l d Automobile R e s t r a i n t s : Evaluation of Health Education. P e d i a t r i c s , V o l . 59, No. 6, June 1977, p. 907-911. 51. Pless, I.B., Roghmann, K., and A l g r a n a t i , P. The Prevention of I n j u r i e s t o Children i n Automobiles. P e d i a t r i c s , V o l . 49, No. 3, March 1972, p. 420-427. 52. Simons, P.S. F a i l u r e of P e d i a t r i c i a n s to Provide Automobile Restraint Information to Parents. P e d i a t r i c s , V o l . 60, No. 4, Part 2, Oct. 1977, p. 646-648. 53. A l l e n , D.B., and Bergman, A.B. S o c i a l Learning Approaches to Health Education: U t i l i z a t i o n of Infant Auto Restraint Devices. P e d i a t r i c s , V o l . 58, No. 3, September 1976, p. 323-328. 61 54. Reisinger, K.S., Williams, A.F., Wells, J.K., John, C.E., Roberts, T.R., and Podgainy, H.J. E f f e c t of P e d i a t r i c i a n s ' Counselling on Infant Restraint Use. P e d i a t r i c s , V o l . 67, No. 2, February, 1981, p. 201-206. 55. Waller, P.F., Barry, P.Z. Seat B e l t s : A Comparison of Observed and Reported Use. U n i v e r s i t y of North Carolina Highway Safety Research  Center, Chapel H i l l , 1969. 56. Fhaner, G., Hane, M. Seat B e l t s : The Importance of S i t u a t i o n a l Factors. Accid. Anal. & Prev., V o l . 5, 1973, p. 267-285. 57. Hoadley, M.R., Macrina, D.M., and Peterson, F.L. C h i l d Safety Programs: Implications A f f e c t i n g Use of C h i l d Restraints. Journal of  School Health, May 1981, p. 352-355. 58. Geddis, D.C, and Spears, G.F. Why Parents Do Not Provide Automobile Restraints f o r Their Children. A u s t r a l i a n P e d i a t r i c Journal, V o l . 16, 180, p. 114-116. 59. C h i l d Safety Seat Pr o j e c t . South Carolina Department of Health  and Environmental Control, Columbia, S. Carolina. 60. L i f e i s Precious. Buckle Them In. M i n i s t r y of Transportation and  Communications, Government of Ontario, Toronto, Ontario, 1982. 61. Burdette, Walter J . , and Gehan, Edmund A. Planning and Analysis of C l i n i c a l Studies. Charles C. Thomas Publisher, 1970, p. 33-38. 62. Armitage, P. S t a t i s t i c a l Methods i n Medical Research. John Wiley  and Sons Inc., 1971, pp. 184-188. 63. Freeman, J.A., Thomas, C.C, Smith, H. J r . , and Kuebler, R.R. The Importance of Beta, the Type II E r r o r and Sample Size i n the Design and Interp r e t a t i o n of the Randomized C l i n i c a l T r i a l . New England Journal of  Medicine, Sept. 28, 1978, p. 690-694. 64. Dillman, D.A. M a i l and Telephone Surveys: The T o t a l Design Method. Wiley, New York, 1977. 65. Emory, CW. Business Research Methods. Richard D. Irwin, Inc. Homewood, I l l i n o i s , 1976. 66. Survey Research. Report of the Consultative Group on Survey  Research, The Canada Council, M i n i s t e r of Supply and Services, Ottawa, 1976. 67. Labaw, P. Advanced Questionnaire Design. Abt Books, Cambridge, Massachusetts, 1980. 68. Fhaner, G., Hane, M. Seat B e l t s : Factors Influencing Their Use. Accid. Anal. & Prev., V o l . 5, 1973, p. 27-43. 62 69. Helsing, K.J., Comstock, G.W. What Kinds of People Do Not Use Seat Belts? American Journal of P u b l i c Health, V o l . 67, No. 11, Nov. 1977, p. 1043-1050. 70. Agent, K.R., Barclay, M. and Deen, R.C. Use of Safety Belts i n Kentucky. Kentucky Department of Transportation, Lexington, 1978. 71. Robertson, L.S., O ' N e i l l , B., and Wixom, C.W. Factors Associated with Observed Safety B e l t Use. Journal of Health and S o c i a l Behaviour, March, 1972. 72. Lachin, J.M. Introduction to Sample Size Determination and Power Analysis f o r C l i n i c a l T r i a l s . C o n t r o l l e d C l i n i c a l T r i a l s , 2, 1981, p. 93-113. 64 Educational Package; Other Inclusions 1. Myth and Facts About C h i l d Car Safety, U.S. Department of Transportation, National Highway T r a f f i c Safety Administration, DOT HS 806 046. 2. Dear Abby column, A b i g a i l Van Buren, Vancouver Province, 12 August, 1982. 3. Keep Them Safe, Transport Canada, M i n i s t e r of Supply and Services Canada, Ottawa, 1982, Cat. No. T22-60/1982. 65 Appendix I I Sample Si z e Determination Comparing r e s t r a i n t usage between two groups, each of s i z e 120, a c h i -square t e s t would conclude that there i s a s i g n i f i c a n t d i f f e r e n c e (p-value about .05 or less) f o r a v a r i e t y of proportions d i f f e r i n g by about .10 (10%) or more. For example: 18 30 102 90 15% versus 25%, P" -value = .053 120 120 42 60 78 60 35% versus 50%, P -value = .019 120 120 60 75 60 45 50% versus 62.5%, P" -value = .051 120 120 96 108 24 12 80% versus 90%, P" -value = .030 120 120 66 endix III I n i t i a l Questionnaire: Pre-prograr Dr. Ronald Sax Vancouver Health Department DATE: 2610 Victoria Drive Vancouver, B.C. V5N 4L2 INFANT CAR SEAT PROJECT NAME: f i r s t last ADDRESS: Postal Code: TELEPHONE: YOUR DATE OF BIRTH: day month year MARITAL STATUS: (please check one) single married ocrmionlaw_ divorced separated 1. Is your new baby: a g i r l : 2. Is this your f i r s t child: a boy: no —Wow many other children have you had? number_ yes 3. Do you own or have access to a car: no -ves in an infant car seat? How did you obtain this seat? (please check one) bought new bought used_ rented Reason for not using a seat: (please check one) never thought about i t too expensive borrowed^ had one from a previous child received as a g i f t other (specify) ~ do not think they work do not think they are needed_ too much bother haven't got around to i t child i s too restricted car i s unsuitable other (specify) 4. Do you wear a seatbelt when driving or riding in a car? always (100%) frequently (51-99%) occasionally (1-50%F never (0%) " Do you smoke cigarettes? more than 1 pack per day_ *5 to 1 pack per day less than h pack per day quit smoking_ never smoked (when 67 Appendix III i i ) I n i t i a l Questionnaire: Program Dr. Ronald Sax Vancouver Health Department 2610 V i c t o r i a Drive Vancouver, B.C. V5N 4L2 INFANT CAR SEAT PROJECT DATE: NAME: f i r s t l a s t ADDRESS: Po s t a l Code: TELEPHONE: YOUR DATE OF BIRTH: day month year MARITAL STATUS: (please check one) s i n g l e married ccmmonlaw_ divorced separated 1. Is your new baby: a g i r l : 2. Is t h i s your f i r s t c h i l d : a boy: no —>How many other c h i l d r e n have you had? number_ yes 3. Do you own or have access to a car: no -yes i n an i n f a n t car seat? How d i d you obtain t h i s seat? (please check one) bought new bought used rented ~ borrowed Reason f o r not using a seat: (please check one) never thought about i t too expensive had one frcm a previous c h i l d received as a g i f t _ other (specify) do not think they work do not think they are needed_ too much bother haven't got around to i t c h i l d i s too r e s t r i c t e d car i s unsuitable other (specify) 4. Do you wear a seatbelt when d r i v i n g or r i d i n g i n a car? always (100%) frequently (51-99%)_ o c c a s i o n a l l y (1-50%) never (0%) 5. Do you smoke ci g a r e t t e s ? more than 1 pack per day_ *5 to 1 pack per day q u i t smoking_ never smoked (when less than h pack per day_ 6. Did you watch the f i l m " L i f e i s Precious" (about i n f a n t and c h i l d car seats) while you were i n h o s p i t a l ? yes 68 Appendix III i i i ) Cover L e t t e r : I n i t i a l Questionnaire IH nons gate nospcai 230 EAST 1 3 T H STREET. NORTH VANCOUVER. 0 C V71 217 PHONE (60-1 ] 98(1-3 I31 H:.U:> :15:>("I0:-. INFANT CAR SEAT PNOJECT The questions which cane with this letter may help you to think about your baby's safety in cars. The question sheet is part of a study being done by Lions Gate Hospital and the Vancouver Health Department to learn about the use of infant car seats in Vancouver and nearby areas. Completion of the questionnaire is voluntary and is not related to your care while in hospital. Your answers would be useful to our study and should take you only a few minutes to f i l l out. We may contact you later to ask a few more ques-tions. A l l questionnaires will be kept confidential. The study will not report any names or personal identification. If completed, your consent is given to use your answers in our study. When you complete the questionnaire you can return i t to the ward desk. Thank you for your help. Ronald Sax M.D. Project Director SURREY MEMORIAL HOSPITAL 1.1750."Huh AVE.. SURREY. B.C. V.IV IZ; Trlrplidiic 5XI-22II . Tr io 04.1SI 23 INFANT CAR SEAT PROJECT The questions which acme with this letter may help you to think about your baby's safety in cars. The question sheet is part of a study being done by Surrey Memorial Hospital and the Vancouver Health Department to learn about the use of infant car seats in Vancouver and nearby areas. Completion of the questionnaire is voluntary and is not related to your care while in hospital. Your answers would be useful to our study and should take you only a few minutes to f i l l out. We may contact you later to ask a few more questions. A l l questionnaires will be kept confidential. The study will not report any names or personal identification. If completed, your consent is given to use your answers in our study. V.Tien you complete the questionnaire, you con return i t to the ward desk. Thank you for your help. Ranald Sax M.D. Project Director 69 Appendix I I I iv) Follow-up Questionnaire Cr. Ponald Sax 7anco\J\'er Health Deparmer.t 2610 V i c t o r i a Drive Vancouver, B.C. V5N 4L2 TOLLOWUP INFANT CAR SEAT PROJECT DATE: 1. Do you have an i n f a n t car seat for your baby? no_ -yes o f t e n do you use t h i s seat? always (100%) frequently (51-99%)_ o c c a s i o n a l l y (1-50%) never (0%) 2. What language do you y o u r s e l f speak at heme now? ( I f more than one language, which language do you speak most often?) Check one only E n g l i s h Portuguese QvLnese French Spanish Japanese I t a l i a n Punjabi Vietnamese Greek Hindi Other (specify) 3. What i s the highest grade or year of secondary (high) or elementary school you have ever attended? no schooling or kindergarten only 1-6 7-9 10-13 . post-secondary education: non-university post-secondary education: u n i v e r s i t y What was the l a s t job you held before your baby was born? (eg. s e c r e t a r y , student, t a x i d r i v e r , teacher, hemernaker/housewife, etc.) 5. B r i e f l y describe the kind of work you do i n your job. 6. What was the t o t a l income for your family i n 1982? (before taxes) under $9,999 $10,000-$14,999 $15,000-S19,999 S20,000-S24,999 $25,000-$29,999 S30,000-S39,999 over $40,000 7. Do you smoke c i g a r e t t e s ? nore than 1 pack per day H-l pack per day l e s s than S pack per day q u i t smoking (wtien? ) never smoked 70 Appendix III v) Cover L e t t e r : Follow-up Questionnaire VANCOUVER HEALTH DEPARTMENT 26io v i c r o n i A O H I V E . V A N C O U V E R , B .C . V S N AL2 872 E A S T UNIT F I L E Dear The C i ty Health Department and Lions Gate Hospital are conducting a study to learn about the use of infant car seats in Vancouver. When you were in hospital to d e l i v e r your baby, vou completed a Question-na i re . The information you provided has helped us in the f i r s t nart of our study. We would l i ke to ask you a few more auestions about vourse l f and your family for the second oart of the study. The resu l ts of th is research w i l l help us to plan education oroarammes on the use of infant and c h i l d car seats. In order that the resu l t s of the study t ru ly represent the s i t ua -t ion in the community, i t is important that each Questionnaire be com-pleted and returned. Completion of the Questionnaire is voluntary. It should onlv take you a few minutes to f i l l out. Please return i t in the stamped, ore-addressed envelope. You may be assured of complete c o n f i d e n t i a l i t y . The Question-naire has an i d e n t i f i c a t i o n number for mail ing purposes only. This is so that we may check your name o f f of the mai l inc l i s t when vour Questionnaire i s returned. Your name w i l l never be placed on the auestionnai re. The resu l t s of the study should be ava i l ab le by the end of Octo-ber. If you are interested in our f ind ings , please contact me at that time. I would be happy to answer any questions you miaht have. p l e a se c a l l me i f you have any concerns. Si ncerely Ronald Sax M.D. Ass i s tant Medical Health O f f i c e r Project D i rector 72 Appendix III v i i ) Follow-up L e t t e r VANCOUVER HEALTH DEPARTMENT 2610 VICTORIA ORIVE. VANCOUVER. B.C. VSN 4L2 y EAST UNIT FILE i Dear About three weeks ago I wrote to you to ask several questions about yourself and your family. As of today, we have not yet received your com-pleted questionnaire. This study was undertaken to enable us to plan education programs to prcrote tlie use of infant and child car seats. I am writing to you again because of the significance each questionnaire has to the usefulness of this study. In order for the results to be truly representative, i t is inportant that each questionnaire be carp le ted and returned; however, i f you do net wish to answer any specific question, i t may be left blank. Completion of the questionnaire is voluntary, but i t should only take you a few minutes to f i l l out. A replacement questionnaire is enclosed with a stamped, pre-addressed envelope. You may be assured of ccnplete confidentiality. The questionnaire has an identification number for mailing purposes only. This is so that we may check your name off of the mailing l i s t when your questionnaire is returned. Your name w i l l never be placed on the questionnaire. Your cooperation is greatly appreciated. Sincerely Ronald Sax M.D. Assistant Medical Health Officer Project Director 74 Appendix V Comparability of H o s p i t a l Subject Populations: Pre-program Groups i ) Mother's Age Age i n years X 2 = 25.03 DF = 4 p < .001 15-19 20-24 25-29 30-34 35 + Hospital Lions Gate 3 (2.4%) ( 12.0%) (41 .6%) (34.4%) (9.6%) 15 52 43 12 125(100.0%) 41 Surrey 7 (5.0%) (29.5%) 64 (46.0%) 24 (17.3%) 3  139(100.0%) 10 56 116 67 15 264 i i ) M a r i t a l Status Lions Gate Single Married Common Law Separated 5 113 9 1 (3.9%) (88.3%) (7.0%) (0.8%) 128(100.0%) Surrey 8 (5.3%) 126 (83.4%) 15 (9.9%) 2 (1.3%) 151(100.0%) 13 239 24 3 279 i i i ) Mother's F i r s t C h i l d No Yes X 2 = .99 DF = 1 p > .3 Lions Gate 69 (54.3%) 58 (45.7%) 127(100.0%) Surrey 73 (48.3%) 78 (51.7%) 151( 100.0%) 142 136 278 75 Hospital iv) Seat B e l t Use Always Frequently Occasionally Never Lions Gate 90 (70.3%) 26 (20.3%) 12 (9.4%) 128(100.0%) Surrey 96 (63.6%) 37 (24.5%) 18 (11.9%) 151(100.0%) 186 63 30 279 X" = 1.43 DF = 2 p > .4 v) Education Lions Gate Surrey 0-12 45 (39.1%) 86 (66.7%) 131 Years or 13 32 (27.8%) 27 (20.9%) 59 Type Post-secondary 38 (33.1%) 16 (12.4%) 54 115(100.0%) 129(100.0%) 244 X 2 = 21.49 DF = 2 p < .001 v i ) Family Income Lions Gate Surrey < $9,999 7 (16.7%) 7 (11.3%) 14 $10,000 - $19,999 6 (14.3%) 11 (17.7%) 17 $20,000 - $29,999 7 (16.7%) 14 (22.6%) 21 $30,000 - $39,999 8 (19.0%) 11 (17.7%) 19 > $40,000 14 (33.3%) 19 (30.7%) 33 42(100.0%) 62(100.0%) 104 X 2 = 1.23 DF = 4 p > .8 76 Hospital v i i ) Language Lions Gate Surrey English 111 (95.7%) 122 (93.9%) 233 Other 5 (4.3%) 8 (6.1%) 13 116(100.0%) 130(100.0%) 246 X 2 = .42 DF = 1 p > .5 v i i i ) Smoking Behaviour Lions Gate Surrey D a i l y > 1 pack 4 (3.2%) 11 (7.4%) 15 Cigarette 1/2 - 1 pack 10 (8.1%) 27 (18.1%) 37 Smoking < 1/2 pack 10 (8.1%) 7 (4.7%) 17 Quit 41 (33.1%) 39 (26.2%) 80 Never Smoked 59 (57.6%) 65 (43.6%) 124 124(100.0%) 149(100.0%) 273 X 2 = 9.74 DF = 4 p < .05 77 Appendix VI Comparability of Groups Within Each Ho s p i t a l Separately a) Lions Gate i ) Mother's Age Age i n Years X 2 = 3.59 DF = 4 p > .4 15-19 20-24 25-29 30-34 35 + Pre-program 3 (2.4%) 15 (12.0%) 52 (41.6%) 43 (34.4%) 12 (9.6%) 125(100.0%) Group Program 1 (0.8%) 20 (16.5%) 40 (33.1%) 45 (37.2%) 15 (12.4%) 121(100.0%) 4 35 92 88 27 246 i i ) M a r i t a l Status Pre-program Program Single Married Common Law Separated 5 113 9 1 (3.9%) (88.3%) (7.0%) (0.8%) 128(100.0%) 5 (3.9%) 118 (91.5%) 6 (4.6%) 0  129(100.0%) 10 231 15 1_ 257 i i i ) Mother's F i r s t C h i l d Pre-program Program No Yes 69 (54.3%) 58 (45.7%) 127(100.0%) 73 (56.6%) 56 (43.4%) 129(100.0%) 142 114 256 X 2 = .13 DF = 1 p > .7 78 Group iv) Seat B e l t Use Pre-program Program Always 90 (70.3%) 100 (77.5%) 190 Frequently 26 (20.3%) 24 (18.6%) 50 Occasionally 12 (9.4%) 5 (3.9%) 17 Never 128(100.0%) 129(100.0%) 257 X 2 = 3.48 DF = 2 p > .1 v) Smoking Behaviour Pre-program Program D a i l y > 1 pack 4 (3.2%) 4 (3.1%) 8 Cigarette 1/2 - 1 pack 10 (8.1%) 14 (10.9%) 24 Smoking < 1/2 pack 10 (8.1%) 11 (8.6%) 21 Quit 41 (33.1%) 48 (37.5%) 89 Never Smoked 59 (47.6%) 51 (39.8%) 110 124(100.0%) 128(100.0%) 252 X 2 = 1.78 DF = 4 p > 0.7 v i ) Education Pre-program Program Years 0-12 45 (39.1%) 53 (43.4%) 98 or 13 32 (27.8%) 31 (25.4%) 63 Type Post-secondary 38 (33.0%) 38 (31.2%) 76 115(100.0%) 122(100.0%) 237 X 2 = 0.46 DF = 2 p > .79 79 X* = 3.68 DF = 4 p > 0.45 Group v i i ) Family Income Pre-program Program < $9,999 $10 ,000 - $19,999 $20,000 - $29,999 $30,000 - $39,999 > $40,000 7 6 7 8 14 ( 16.7%) (14.3%) ( 16.7%) (19.0%) (33.3%) 7 6 6 20 16 (12.7%) (10.9%) (10.9%) (36.4%) (29.1%) 42(100.0%) 55(100.0%) 14 12 13 28 30 97 v i i i ) Language Pre-program Program Engli s h Other 111 (95.7%) 5 (4.3%) 116(100.0%) 116 (95.1%) 6 (4.9%) 122(100.0%) 227 11 238 X 2 = .50 DF = 1 p > .8 b) Surrey i ) Mother's Age Age i n Years 15-19 20-24 25-29 30-34 35 + Pre-program 7 41 (5.0%) (29.5%) 64 (46.0%) 24 (17.3%) 3 (2.2%) 139(100.0%) Program 6 31 (4.4%) (22.6%) 59 (43.1%) 32 (23.4%) 9 (6.6%) 137(100.0%) 13 72 123 56 12 276 X^ = 5.80 DF = 4 p > .2 80 Group i i ) M a r i t a l Status Pre-program Program Single 8 (5.3%) 8 (5.5%) 16 Married 126 (83.4%) 129 (88.4%) 255 Common Law 15 (9.9%) 9 (6.1%) 24 Separated 2 (1.3%) 0 2 151(100.0%) 146(100.0%) 297 i i i ) Mother's F i r s t C h i l d Pre-program Program No 73 (48.3%) 80 (54.8%) 153 Yes 78 (51.7%) 66 (45.2%) 144 151(100.0%) 146(100.0%) 297 X 2 = 1 .24 DF = 1 p > .2 iv) Seat B e l t Use Pre-program Program Always 96 (63.6%) 101 (69.2%) 197 Frequently 37 (24.5%) 29 (19.9%) 66 Occasionally 18 (11.9%) 16 (11.0%) 34 Never 151(100.0%) 146(100.0%) 297 X 2 = 1.13 DF = 2 p > .5 81 v) Smoking Behaviour Group Pre-program Program Daily > 1 pack 11 (7.4%) 10 (6.9%) 21 Cigarette 1/2 - 1 pack 27 (18.1%) 25 (17.2%) 52 Smoking < 1/2 pack 7 (4.7%) 15 (10.3%) 22 Quit 39 (26.2%) 35 (24.1%) 74 Never Smoked 65 (43.6%) 60 (41.4%) 125 149(100.0%) 145(100.0%) 294 X 2 = 3.40 DF = 4 p > .4 v i ) Education Pre-program Program Years 0-12 86 (66.7%) 80 (64.0%) 166 or 13 27 (20.9%) 34 (27.2%) 61 Type Post-secondary 16 (12.4%) 11 (8.8%) 27 129(100.0%) 125(100.0%) 254 X 2 = 1.88 DF = 2 p > .3 v i i ) Family Income Pre-program Program X" = 3.91 DF = 4 p > 0.4 < $9,999 $10,000 - $19,999 $20,000 - $29,999 $30,000 - $39,999 > $40,000 7 11 14 11 19 (11.3%) ( 17.7%) (22 .6%) ( 17.7%) (30 .7%) 9 8 7 16 19 (15.3%) (13.6%) (11.9%) (27.1%) (32 .2%) 62( 100 .0%) 59(100.0%) 16 19 21 27 38 121 82 v i i i ) Language Pre-program Program Engli s h 122 (93.8%) 118 (92.2%) 240 Other 8 (6.2%) 10 (7.8%) 18 130(100.0%) 128(100.0%) 258 X 2 = .27 DF = 1 p > .6 83 Appendix VII Comparability of Subjects Observed to Subjects Not Observed i ) Mother's Age Subjects Observed Not Observed Age i n 15-19 10 (3.7%) 6 (2.6%) 16 Years 20-24 53 (19.7%) 46 (20.0%) 99 25-29 106 (39.4%) 98 (42.6%) 204 30-34 79 (29.4%) 63 (27.4%) 142 35 + 21 (7.8%) 17 (7.4%) 38 269(100.0%) 230(100.0%) 499 X z = 0.99 DF = 4 p > .9 i i ) Seat B e l t Use Observed Not Observed Always 211 (73.3%) 165 (68.8%) 376 Frequently 55 (19.1%) 52 (21.7%) 107 Occasionally 22 (7.6%) 23 (9.6%) 45 Never 228(100.0%) 240(100.0%) 528 X 2 = 1.38 DF = 2 p > .5 84 i i i ) Smoking Behaviour Subjects X^ = 4.71 DF = 4 p > .3 Observed Not Observed Daily Cigarette Smoking > 1 pack 1/2 - 1 pack < 1/2 pack Quit Never Smoked 15 (5.3%) 35 (12.5%) 17 (6.0%) 89 (31.7%) 125 (44.5%) 281(100.0%) 11 (4.6%) 37 (15.5%) 24 (10.0%) 64 (26.8%) 103 (43.1%) 239(100.0%) 26 72 41 153 228 520 i v ) Education Observed Not Observed Years 0-12 130 (51.2%) 121 (5.6.3%) 251 or 13 62 (24.4%) 55 (25.6%) 117 Type Post-secondary 62 (24.4%) 39 (18.1%) 101 254(100.0%) 215(100.0%) 469 X 2 = 2.76 DF = 2 p > .2 v) Family Income Observed Not Observed < $9,999 18 (7.6%) 7 (3.5%) 25 $10,000 - $19,999 27 (11.3%) 34 (17.2%) 61 $20,000 - $29,999 61 (25.6%) 59 (29.8%) 120 $30,000 - $39,999 51 (21.4%) 42 (21.2%) 93 > $40,000 81 (34.0%) 56 (28.3%) 137 238(100.0%) 198(100.0%) 436 X 2 = 7.50 DF = 4 p > .1 85 v i ) Language Subjects X^ = .72 DF = 1 p > .3 Observed Not Observed English Other 245 12 (95.3%) (4.7%) 257(100.0%) 203 14 (93.5%) (6.5%) 217(100.0%) 448 26 474 86 Appendix VIII Comparability of Consistent Subjects and Subjects Observed,  to be Not Consistent with Respect to Self-Report i ) Mother's Age Subjects X 2 = 14.11 DF = 4 p < .01 Consistent Not Consistent Age i n Years 15-19 20-24 25-29 30-34 35 + 5 33 84 65 19 (2.4%) (16.0%) (40.8%) (31 .6%) (9.2%) 5 20 22 14 2 (7.9%) (31.7%) (34.9%) (22.2%) (3.2%) 206(100.0%) 63( 100 .0%) 10 53 106 79 21 269 i i ) Seat B e l t Use Consistent Not Consistent Always 166 (75.8%) 45 (65.2%) 211 Frequently 41 (18.7%) 14 (20.3%) 55 Occasionally 12 (5.5%) 10 (14.5%) 22 Never 219(100.0%) 69(100.0%) 288 X 2 = 6.45 DF = 2 p < .05 i i i ) Smoking Behaviour Consistent Not Consistent D a i l y > 1 pack 10 (4.7%) 5 (7.2%) 15 Cigarette 1/2 - 1 pack 24 (11.3%) 11 (15.9%) 35 Smoking < 1/2 pack 13 (6.1%) 4 (5.8%) 17 Quit 73 (34.4%) 16 (23.2%) 89 Never Smoked 92 (43.4%) 33 (47.8%) 125 212(100.0%) 69(100.0%) 281 X 2 = 3.83 DF = 4 p > .4 87 i v ) Education Subjects Consistent Not Consistent Years or Type 0-12 13 Post-secondary 93 (47.2%) 53 (26.9%) 51 (25.9%) 197(100.0%) 37 (64.9%) 9 (15.8%) 11 (19.3%) 57(100.0%) 130 62 62 254 X^ = DF = P > = 5.73 = 2 .05 v) Family Income Consistent Not Consistent < $9,999 12 (6.4%) 6 (12.0%) 18 $10,000 - $19,999 19 (10.1%) 8 (16.0%) 27 $20,000 - $29,999 47 (25.0%) 14 (28.0%) 61 $30,000 - $39,999 41 (21.8%) 10 (20.0%) 51 > $40,000 69 (36.7%) 12 (24.0%) 81 188(100.0%) 50(100.0%) 238 X 2 = 4.92 DF = 4 p > .2 v i ) Language Consistent Not Consistent En g l i s h Other 191 7 (96.5%) (3.5%) 198(100.0%) 54 5 (91.5%) (8.5%) 59(100.0%) 245 12 257 X2 DF P 3 = 2.49 = 1 .1 88 I Appendix IX Variables Possibly Associated with Restraint Use: Self-Report Combined Lions Gate Surrey Not Not Not Variable Used Used Used Used Used Used i) Marital Status Single 18 3 21 7 2 9 1 1 1 12 Married 414 55 469 2Q9 17 226 205 38 243 Common-Law 25 1 1 36 10 4 14 15 7 22 Separated 2 0 2 0 0 0 2 0 2 459 69 528 226 23 249 233 46 279 Marital Status Married 4 14 55 469 209 17 226 205 38 243 Other 45 14 59 17 6 23 28 8 36 459 69 528 226 23 249 233 46 279 X 2 = 6.64 X 2 8.58 X 2 = 0 .99 DF = 1 DF 1 DF = 1 P < .0 1 P < .01 P = .32 i i ) F i r s t C h i l d Yes 235 20 255 105 6 121 120 14 134 No 233 49 282 120 17 137 113 32 145 468 69 537 225 23 258 233 46 279 X 2 = 9.77 X 2 3.57 X 2 = 6.83 DF = 1 DF 1 DF « 1 P = .0 1 P .06 P = .0 1 i i i ) Seat Belt Use Always 339 37 376 172 13 185 167 24 191 Frequently 86 21 107 43 6 49 43 15 58 Occasionally 34 1 1 45 11 4 15 23 7 30 Never 459 69 528 226 23 249 233 46 279 X 2 = 12.63 X 2 = 7.04 X 2 - 5.67 DF = 2 DF = 2 DF = 2 P = .00 1 P = .03 P = .059 89 Combined (.ions Gate Surrey Not Not Not Va r i a b l c Used Used Used Used Used Used i v l Education 0-12 years 216 35 251 88 9 97 128 26 154 13 years 104 13 1 17 56 4 60 48 9 57 Post-seconda ry 92 9 10 1 68 _6 74 24 _3 27 4 12 57 469 212 19 23 1 200 38 238 X 2 = 1 .87 X 2 = 0.34 X 2 = 0 .57 DF = 2 DF = 2 DF = 2 P = .39 P = .84 P = .62 v) Family Income < $9,999 16 9 25 9 3 12 7 6 13 510,000 - $19,999 51 10 61 22 3 25 29 7 36 520,000 - S29,999 103 17 1 20 52 6 58 51 11 62 530,000 - 539,999 84 9 93 33 2 35 51 7 58 > 540 ,000 130 7 137 84 6 90 46 1 47 384 52 436 200 20 220 184 32 216 X 2 - 22.03 X 2 - S.16 X 2 = 17 DF = 4 DF = 4 DF = 4 P < .00 1 P = .27 P = .002 vi) Smoking Behaviour > 1 pack 2 1 5 26 6 2 8 15 3 18 1/2 - 1 pack 52 20 72 18 6 24 34 14 48 < 1/2 pack 32 9 4 1 17 2 19 15 7 22 Quit 144 9 153 79 7 86 65 2 67 Never Smoked 203 "25 228 101 6 107 102 11 121 452 68 520 221 23 244 231 45 276 X 2 - 25.26 X 2 = 11.11 X 2 = 1 8.44 DF = 4 DF = 4 DF = 4 P < .00 1 P ** .03 P " .001 v i i ) Language English 400 48 448 205 16 22 1 195 32 227 Other 15 1 1 26 7 4 1 1 8 _2 15 415 59 474 212 20 232 203 39 242 X 2 = 22.51 X 2 = 1 1.28 X 2 = 1 1 .04 DF = 1 DF = 1 DF = 1 P < .00 1 P < .00 1 P < .00 1 90 Combi ned L i o n s G a t e V a r i a b l e Used Not Used Used Not Used v i i i ) M o t h e r ' s Age Mean 28.03 26.73 29.3S 26.9 1 V a r i a n c e 20 .53 23.75 19.77 20 .99 N 436 63 217 21 T = -2 .11 T = - 2 . 4 0 DF = 497 DF. = 236 P = .03 P = .02 S u r r e y Not Used Used 26.73 26.64 17.96 25.65 2 19 42 T = - . 1 2 DF = 259 P = .9 1 91 Appendix X Variables Possibly Associated with Restraint Use: Observation Combined Lions Gate Variable i) M arital Status S ingle Married Common-Law Separated Marital Status Married Other i i ) F i r s t Child Yes No i i i ) Seat Belt Use Always Frequently Occasionally Never 10 193 7 2 212 193 19 212 X 2 = DF = P = Not Used 7 75 10 0 92 75 17 92 5.57 1 .0 18 107 104 211 38 54_ 92 X* = 2.27 DF « 1 p = .13 162 36 14 57 23 12 92 212 X 2 •= 7.10 DF = 2 p = .029 1 7 268 17 2 304 268 36 304 145 158 30 3 219 59 26 304 Used 6 123 4 0 133 123 10 133 Not Used 2 13 1 0 16 2 _ 13 _3 16 2.26 1 .13 63 69 132 X 2 -DF « P " 9 7 16 .52 97 26 10 133 16 X 2 = 2.83 DF = 2 p = .24 8 136 5 0 149 136 13 149 72 76 148 106 30 13 Surrey 4 70 3 _2 79 70 9 79 Not Used 5 62 9 _0 76 62 14 76 X* = 1 .51 DF = 1 p = .22 44 35 79 29 47 76 X' = 4.78 DF = 1 p = .03 65 10 4 48 19 9 76 = 7.22 = 2 = .027 9 132 12 2 155 132 23 155 73 82 155 113 29 13 15S 92 Combi nod Not Variable Used Used iv) Education 0-12 years 88 49 13 years 51 15 Post-secondary 52 l 2 191 76 X 2 - 7.62 OF = 2 P = .02 v) Family Income < $9,999 12 9 $10 ,000 - $19,999 20 8 $20,000 - $29,999 46 17 $30,000 - $39,999 38 15 > $40,000 70 14 186 63 X 2 - 7.24 DF = 4 P = .12 vi) Smoking Behaviour > 1 pack 9 7 1/2-1 pack 21 16 < 1/2 pack 9 10 Quit 76 18 Never Smoked 90 41 205 92 X 2 = 14.15 DF = 4 P < .0 1 v i i ) Language English 185 7 1 Other 7 7 192 78 X 2 = 3.2 DF = 1 P = .07 Lions Gate Surrey Not Not Used Used Used Used 137 49 5 54 39 44 83 66 30 4 34 21 11 32 64 43 _5 48 J3 _7 16 267 122 14 136 69 62 131 X 2 = 0.14 X 2 = 3 .3 1 DF = 2 DF = 2 P = 0.93 P = .19 2 1 9 1 10 3 8 1 1 28 12 0 12 8 8 16 63 28 6 34 18 1 1 29 53 18 0 18 20 15 35 84 52 6 58 18 _8 26 249 1 19 13 132 67 50 1 17 X 2 = 5.62 X 2 - 6 . 18 DF = 4 DF = 4 P = .23 P = .19 16 6 1 7 3 6 9 37 1 1 1 12 10 15 25 19 5 3 8 4 7 11 94 52 6 58 24 12 36 131 54 _5 59 36 36 72 297 128 16 144 77 76 153 X 2 - 6.26 X 2 = 6.81 DF = 4 DF = 4 P = .18 P = .15 256 1 17 14 131 68 57 125 14 5 0 5 2 7 9 270 122 14 136 70 64 134 X 2 - .60 X 2 = 3 .48 DF = 1 DF = 1 P = .44 P = .06 93 Variable v i i i ) Mother * s Age Mean Variance N Combi ned Not Used Used 28.60 26.03 20.89 19.52 198 87 T = 4.40 DF = 283 P < .00 1 Lions Gate Not Used Used 29.15 27.07 21 .97 20 .07 126 15 T = 1 .64 DF = 139 P = .10 Surrey Not Used Used 27.63 25.82 17 .79 19.42 72 72 T = 2.51 DF = 142 P = .0 1 9 4 Appendix XI Three-Way Table: Observed Restraint Use Use, Family Income, Education PAGE 4 BMDP JF i n f a n t c a r r e s t r a i n t program N U M B E R O F V A L U E S V A R I A B L E M£AN S T A N D A R D S M A L L E S T L A R G E S T T O T A L M I S S I N G BE LOW A B O V E NOT E Q U A L TO N O . NAME D E V I A T I O N V A L U E V A L U E F R E Q U E N C Y M I N I M U M M A X I M U M S T A T E D C O O E S 455 383 I N T E R V A L RANGE V A R I A B L E MINIMUM MAXIMUM M I S S I N G CATEGORY C A T E GORY G R E A T E R L E S S THAN N O . NAME L I M I T L I M I T CODE COOE NAME THAN OR • TO 2 oooco t o 9 3 ooooo t o 9 4 ooooo t o 1 2 5 ooooo t o I 3 6 ooooo p o s t 1 ooooo 1 l 10 2 ooooo t o 2 0 3 ooooo t o 2 0 4 ooooo t o 3 0 5 ooooo t o 3 0 6 ooooo t O 4 0 7 ooooo g t 4 Q 5 o o s u s « 9 . O O O O O 1 - OOOOO y e s 2- OOOOO " O * T A B L E P A H A G R A P H I * OBSERVED FREQUENCY TABLE 1 i n c o o s u s e e d u c t o 9 t o 12 t o 13 p o s t TOTAL I t 10 y e 5 0 6 5 1 12 n o 2 G I 0 9 T O T A L 12 6 1 2 1 t o 2 0 y e s 1 14 2 3 20 n o 2 5 ( 0 8 T O T A L 19 3 3 28 t o 3 0 y e s I 25 1 1 9 46 n o 2 9 3 3 17 T O T A U 34 14 • 2 63 t o J O y e s 1 1 7 1 1 9- 36 n o 7 4 4 15 T O T A L « 24 15 13 53 g t < 0 y e s 0 20 20 30 70 n o 0 5 4 5 t 4 T O T A L 0 25 24 35 84 T O T A L OF T H E a a s E R v E O F R E Q U E N C Y T A B L E IS 349 305 CASE5 HAO INCOMPLETE 0 ATA NUMBER OF E K C L U O E O C A S E S T A B L E t o b t u s e IN RANGE M [ S S I N G • d u e TOOSMALL TOOLARGE UNCOUNTD TOTAL IN RANGE 37 0 0 0 55 M I S S1NG i SO 22 0 0 0 172 TOOSMALL o 0 0 0 0 O T O O L A B G E 0 0 0 0 0 0 UNCOUNTO 74 4 0 0 0 78 TOTAL 243 63 0 0 0 305 95 PAGE 7 BMDP4T i n l r t n t c«r r e s t r a i n t p rogram » L L M O D E L S A R E R E Q U E S T E D - -L I K E L I H O O D -R A T I O C H I S O P E A R S O N C H I S O I T E R A T I O N S e . 3 6 I S 1 0 0 0 . 0 2 1 2 7 0 0 0 o . 3 6 2 2 3 6 8 0 . 0 2 0 6 8 8 0 0 i . 3 5 2 3 1 6 4 0 . 0 2 3 1 7 1 0 0 e . o . 3 5 1 1 7 4 9 O . O O O O 1 2 1 5 0 0 O O O O o . I 3 4 1 6 8 1 3 0 . 0 1 4 5 6 6 0 O O O O 1 . B . 3 2 1 2 5 4 5 0 . 0 0 0 0 1 2 7 6 4 0 O O O O e , o . 1 3 t 6 1 9 4 O . O O O B 7 6 0 9 0 O O O O e o . 3 3 1 0 8 0 6 O . O O O O 1 0 2 9 4 0 O O O O e 1 . 19 8 4 6 7 O . O O O O 7 6 9 1 0 O O O O o 1 . 3 0 1 6 0 9 5 0 . 0 <• 1 3 2 S 1 0 O O O O o . o l . 2 7 5 4 7 7 0 . O 0 1 2 5 7 9 0 0 0 0 0 5 o . e 1 . 1 8 2 1 1 6 0 . 2 7 1 4 2 1 3 7 0 2 6 1 4 1 . e o . 2 8 5 2 S 1 0 . 0 O 3 3 4 8 7 7 0 0 0 8 8 e o . e 1 15 1 1 7 3 0 . 6 9 9 3 1 0 5 8 0 7 8 1 8 e t . o * 1 4 1 3 9 8 0 . 4 5 0 9 1 2 2 1 O 5 8 9 3 o l . e o 3 4 4 5 3 4 0 . 0 0 5 3 3 9 3 1 0 0 2 5 3 e o . e 1 o t 1 1 7 5 6 0 . 7 5 2 0 6 0 0 0 8 7 3 1 U U M B E R O F I N T E G E R W O R D S O F S T O R A G E U S E D I N P R E C E D I N G P R O B L E M 1 2 9 6 C P U T I M E U S E O 1 . 2 1 0 S E C O N D S 96 A p p e n d i x X I I T h r e e - W a y T a b l e : S e l f - R e p o r t e d R e s t r a i n t U s e , F a m i l y I n c o m e , E d u c a t i o n •H car r p j | r » VAR I ABLE NO . N i « [ STANOARO DEVI AT ION S M A L L E S T VALUE LARGEST VALUE N U M Mt S S I N G BELOW MINIMUM TOTAL r R E O U E N C * 528 49 1 455 I N T E R V A L RANGE MINIMUM MAXIMUM M I S S I N G C A T E G O R Y CATEGORY G R E A T E R L E S S THAN L I M I T L I M I T CODE CODE NAME THAN OR • TO ABOVE MAXIMUM L U E S NOT EQUAL TO S T A T E D COOES 2 r e c u s e T A B L E P AQ AGR A PH I • O B S E R V E O F R E O U E N C Y T A B L E 1 s r e p u ^ e e d u c t o 9 t o l 2 n o O 9 T O T A L n o y e s T O T A L t OOOOO n o 2 OOOOO y e s 2 OOOOO t o 9 3 OOOOO t o 9 4 OOOOO t o 1 3 5 OOOOO t o ! 3 6 OOOOO p o s t i OOOOO 1 t to 3 OOOOO t o 2 0 3 OOOOO t o 2 0 4 OOOOO t o 3 0 5 ooooo t o 3 0 6 ooooo t O 4 0 7 ooooo Q U O y e s T O T A L 103 120 n o 0 2 2 y e s 0 4g 35 T O T A L O 51 37 TOTAL Of THE O B S E R V E O FREQUENCY T A B L E IS • 2 0 C A S E S HAO I N C O M P L E T E D A T A . 130 137 NUMBER OF E X C L U D E D C A S E S T A B L E 1 i r t p u j e e d u c IN RANGE M I S S I N G TOOSMALL TOOL A RGE UNCOUNTO TOTAL IN RANGE M I S S I N G TOOSMALL TOOLAOGE UNCOUNTO IOT AL 35 22 59 0 63 94 26 97 ° A G E 7 B M D P U T I n f a n t c a r r e s t r a i n t p r o g r a m A L L M O O E L S A P E R E Q U E S T E O - -L I K E L I H O O D -R A T I O C H I S O P E A R S O N C H I S O I T E R A T I O N S e . 3 6 4 8 3 9 8 0 . 0 5 3 0 1 9 0 0 s . 3 8 4 2 4 4 4 0 . 0 3 9 4 6 1 0 0 i . 3 5 6 0 4 1 1 0 . 0 6 5 6 O S 0 0 e . s . 3 5 1 9 6 4 9 0 . 0 1 8 1 3 4 0 0 s . l 3 4 3 1 6 6 2 0 . 0 3 3 1 1 7 0 . 0 i . e . 3 2 3 7 6 1 6 0 . 0 3 5 5 2 7 0 0 e . s . I . 3 1 8 8 6 7 O . O O O O 1 0 8 3 1 0 O O O O e s . 3 2 1 9 3 2 5 O . O 1 7 0 0 1 0 O e l . 19 3 2 6 5 2 O . O 2 7 6 O S 0 0 s 1 . 3 0 2 9 7 8 5 0 . 0 2 5 4 5 2 0 0 e . s l . 2 7 6 9 9 0 O . O O O O 6 9 8 1 0 O O O O s . e l . 18 3 9 0 3 0 . 0 0 2 8 1 S 3 2 3 0 O O O O 1 . e s . 2 8 B S 4 3 O . O O O O 9 8 7 2 0 O O O O e s . e l . 15 3 5 7 9 0 . 0 0 1 9 4 3 6 5 0 O O O I e t . s 1 . 1 4 2 0 2 6 0 . 1 2 2 0 2 1 9 0 0 0 8 0 7 s ( . e s . 2 4 6 6 6 6 O . O O O O 6 6 2 3 0 O O O O e s . e l . s t l 1 19 5 0 0 . 0 5 2 7 1 8 0 9 0 0 7 9 6 D U M B E R O F I N T E G E R W O R D S O F S T O R A G E U S E O I N P R E C E D I N G P R O B L E M 1 2 9 6 C P U T I M E U S E O 1 . 2 0 9 S E C O N D S 

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