UBC Faculty Research and Publications

Sex-based differences in rates, causes, and predictors of death among injection drug users in Vancouver,… Hayashi, Kanna; Dong, Huiru; Marshall, Brandon David Lewis; Milloy, M-J; Montaner, Julio; Wood, Evan; Kerr, Thomas Mar 15, 2016

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
52383-Hayashi_K_et_al_Sex_based_differences.pdf [ 1.23MB ]
Metadata
JSON: 52383-1.0355767.json
JSON-LD: 52383-1.0355767-ld.json
RDF/XML (Pretty): 52383-1.0355767-rdf.xml
RDF/JSON: 52383-1.0355767-rdf.json
Turtle: 52383-1.0355767-turtle.txt
N-Triples: 52383-1.0355767-rdf-ntriples.txt
Original Record: 52383-1.0355767-source.json
Full Text
52383-1.0355767-fulltext.txt
Citation
52383-1.0355767.ris

Full Text

SEX-BASED DIFFERENCES IN RATES, CAUSES, AND PREDICTORS OF DEATH AMONG INJECTION DRUG USERS IN VANCOUVER, CANADA  Kanna Hayashi Huiru Dong Brandon D. L. Marshall Michael-John Milloy Julio S. G. Montaner Evan Wood Thomas Kerr     ABSTRACT In the present study, we sought to identify rates, causes, and predictors of death among male and female injection drug users (IDUs) in Vancouver, British Columbia, Canada, during a period of expanded public health interventions. Data from prospective cohorts of IDUs in Vancouver were linked to the provincial database of vital statistics to ascertain rates and causes of death between 1996 and 2011. Mortality rates were analyzed using Poisson regression and indirect standardization. Predictors of mortality were identified using multivariable Cox regression models stratified by sex. Among the 2,317 participants, 794 (34.3%) of whom were women, there were 483 deaths during follow-up, with a rate of 32.1 (95% confidence interval (CI): 29.3, 35.0) deaths per 1,000 person-years. Standardized mortality ratios were 7.28 (95% CI: 6.50, 8.14) for men and 15.56 (95% CI: 13.31, 18.07) for women. During the study period, mortality rates related to infection with human immunodeficiency virus (HIV) declined among men but remained stable among women. In multivariable analyses, HIV seropositivity was independently associated with mortality in both sexes (all P < 0.05). The excess mortality burden among IDUs in our cohorts was primarily attributable to HIV infection; compared with men, women remained at higher risk of HIV-related mortality, indicating a need for sex-specific interventions to reduce mortality among female IDUs in this setting.  Keywords: Canada, harm reduction, HIV, mortality, sex, substance abuse, intravenous    INTRODUCTION  Injection drug users (IDUs) are at greater risk of premature death (1). In a recent meta-analysis, Mathers et al. (1) found that mortality was almost 15 times higher among IDUs than in the general population worldwide, and the excess mortality rate was higher among women than men. However, there have been few studies in which mortality patterns have been characterized by sex in this population. One previous study in which sex-based differences in mortality among drug-using populations was investigated was undertaken before the introduction of highly active antiretroviral therapy (HAART) (2), and another had limited statistical power to identify sex-specific predictors of death (3). Unique vulnerabilities among female IDUs have been previously described (4). Alongside the biological susceptibility to progression to and relapse into substance-use disorders (5, 6), female IDUs often experience overlap in their sexual and drug-using networks, predisposing them to sex-based violence and infection with human immunodeficiency virus (HIV) (4, 7, 8).  Although HIV-related disease and overdose are the 2 leading causes of death among IDUs globally (1), little is known about how recent advances in HIV treatment and harm-reduction programming have affected mortality among male and female IDUs. Vancouver, British Columbia, Canada, offers an ideal setting for an investigation of these effects. The city has experienced an HIV epidemic among IDUs (9), but HIV treatment interventions have led to remarkable increases in HAART coverage and declines in HIV incidence among IDUs locally (10, 11). Further, harm-reduction interventions—including needle and syringe programs, supervised injection facilities, and methadone maintenance therapy—have been recently implemented or scaled up (12–14). Therefore, we undertook a sex-based analysis to identify the rates, causes, and predictors of death among male and female IDUs in Vancouver between 1996 and 2011. METHODS Study design, setting, and participants  We pooled participants in 2 ongoing, well-characterized, open prospective cohort studies of drug users in Vancouver that had been operating since 1996: the Vancouver Injection Drug Users Study (VIDUS) and the AIDS Care Cohort to Evaluate Access to Survival Services (ACCESS). The cohorts have been described in detail elsewhere (9, 15). Briefly, the Vancouver Injection Drug Users Study includes a cohort of HIV-seronegative adults who injected illicit drugs in the month before baseline assessment. The AIDS Care Cohort to Evaluate Access to Survival Services includes a cohort of HIV-seropositive adult drug users who used an illicit drug other than cannabis in the month before the baseline interview. The 2 studies used harmonized data collection and follow-up procedures to allow for combined analyses of the HIV-seronegative and HIV-seropositive populations. At baseline and semiannually thereafter, participants answered questions from an interviewer-administered questionnaire, which elicited data about demographic characteristics, drug-using behaviors, and related exposures, and underwent serologic testing for HIV and hepatitis C virus antibodies or HIV disease monitoring as appropriate. Participants received Can$20 at study visits. Both studies were approved by the University of British Columbia/Providence Health Care Research Ethics Board.  For the present study, participants were eligible if they completed the baseline interview and at least 1 follow-up visit between May 1, 1996, and December 31, 2011. We further restricted the AIDS Care Cohort to Evaluate Access to Survival Services sample to individuals who had injected drugs in the previous 6 months at baseline. We compared baseline characteristics of participants who were included in and excluded from the present analyses using the χ2 test and Wilcoxon rank sum test. Primary outcome measures  We ascertained mortality rates and underlying causes of death among participants through confidential record linkage with the British Columbia Vital Statistics Agency. The Vital Statistics Agency database recorded causes of death according to the International Classification of Diseases, Tenth Revisioncodes used in medical records. To avoid potential bias due to long durations between the study visits and death, individuals who died more than 24 months after their last recorded follow-up visit were censored on the last follow-up date. On the basis of previous studies involving IDUs (1, 16, 17), causes of death were classified into the following 8 categories: HIV-related causes, overdose, liver-related causes, homicide, suicide, other accidental causes, other nonaccidental causes, and unknown causes. The corresponding International Classification of Diseases codes are shown in Supplementary Data(available at http://aje.oxfordjournals.org/).  Statistical analyses   For each cause of death, we calculated crude mortality rates (CMR) and 95% confidence intervals for the entire study sample and for men and women separately using the Poisson distribution. Then, we fit age-adjusted Poisson regression models including sex (female vs. male) as the primary independent variable of interest to calculate age-adjusted mortality rate ratios for each specific cause among women compared with men. To determine whether age-adjusted rates of death from 3 common causes (HIV-related causes, overdose, and other nonaccidental causes) have changed over time among men and women, we fit age-adjusted Poisson regression models in 4-year calendar time intervals (1996–1999, 2000–2003, 2004–2007, and 2008–2011) as the primary independent variables of interest, stratified by sex. We also graphically depicted mortality rates from the 3 most common causes of death among men and women, stratified by the same 4-year time intervals. To identify an excess mortality burden in our sample compared with the general population, we calculated standardized mortality ratios for men and women using death rates in an age- and sex-matched British Columbia population from 2004 (the midpoint of the study period) as reported by the provincial statistical agencies (18, 19). The year 2004 was selected because detailed death rates in the British Columbia population between 1996 and 2003 were not available through these agencies' websites (18, 19).  For the analysis of predictors of death, the primary endpoint was all-cause mortality. First, we used Kaplan-Meier methods and the log-rank test to estimate and compare survival probabilities between men and women. Then, we used extended Cox regression to identify time-invariant and time-dependent factors associated with time to all-cause death separately among men and women (20). As recommended by the Institute of Gender and Health at the Canadian Institutes of Health Research (21), we constructed sex-stratified models, rather than a nonstratified model that included interaction terms between sex and explanatory variables, to identify a set of predictors of mortality that might be different between the sexes.  On the basis of previous studies (1, 16, 17), a range of explanatory variables were considered. Time-invariant variables assessed at baseline included ethnicity or ancestry and time since first injection. Time-dependent variables included age, HIV seropositivity, hepatitis C virus seropositivity, and other behavioral variables that referred to the previous 6 months, including unstable housing (e.g., living in single-room occupancy hotels, shelters, other transitional housing, or on the street), heroin injection at least once per day, cocaine injection at least once per day, crack smoking at least once per day, engagement in sex work, self-reported enrollment in addiction treatment (any treatment modalities, including methadone maintenance therapy, detoxification, or residential treatment programs), and the cumulative number of incarceration events experienced between baseline and the date of the follow-up assessment. Variable definitions were consistent with those used in our previous work (15, 22, 23).  First, we compared the baseline characteristics of our sample stratified by sex (female vs. male), using the Pearson's χ2 test for categorical variables and the Wilcoxon rank-sum test for continuous variables. Then, we used an a priori-–defined statistical protocol based on the examination of the Akaike information criterion and type III P values to construct multivariable extended Cox regression models. In brief, we first included in the full multivariable models all explanatory variables that were significantly associated with all-cause mortality at the P < 0.10 level in the univariable analyses. After examining the Akaike information criterion value of the models, we removed the variable with the largest P value and built a reduced model. We continued this iterative process and selected the multivariable models with the lowest Akaike information criterion value. All P values were 2-sided. All statistical analyses were performed using SAS, version 9.3 (SAS Institute, Inc., Cary, North Carolina). RESULTS Study sample  Between May 1996 and December 2011, a total of 2,741 individuals enrolled in the cohorts. As shown in Figure 1, 424 (15.5%) were excluded from the present study: 176 did not report having injected drugs in the previous 6 months at baseline and 248 did not complete any follow-up visit. Compared with participants in the analytical sample (n = 2,317), those excluded had shorter durations of injection drug use (P =0.04) and were less likely to inject heroin or cocaine at least once per day (both P < 0.001), engage in sex work (P<0.001), or test positive for hepatitis C virus antibodies at baseline (P < 0.001). However, they were more likely to be infected with HIV at baseline (P < 0.001). Among those excluded, 10 individuals died during the study period, with a rate of 0.7 (95% confidence interval (CI): 0.4, 1.3) deaths per 100,000 person-years.  The 2,317 IDUs included in the present study were followed for a median of 60.6 months (interquartile range, 32.5–112.9) and contributed 14,904.6 person-years of observation. Of these, 606 (26.2%) individuals, including 199 women and 407 men, did not return for a follow-up visit for more than 24 months and were considered lost to follow-up. However, 46 (7.6%) of the 606 individuals, including 21 women and 25 men, were identified as deceased through the linkage to the Vital Statistics Agency database and were censored at their last study visit date. The remaining 560 individuals were considered alive at the end of the study period. Table 1 summarizes the baseline sample characteristics stratified by sex. As shown, the median age at baseline was 37.2 years (interquartile range, 29.2–43.6), and 794 (34.3%) participants were women.  Rates and causes of death As shown in Table 2, 483 deaths were identified during the study period, yielding a CMR of 32.1 (95% CI: 29.3, 35.0) deaths per 1,000 person-years. Among women, there were 171 deaths, resulting in a CMR of 30.1 (95% CI: 26.0, 34.9) deaths per 1,000 person-years. Among men, there were 312 deaths, and the CMR was 33.2 (95% CI: 29.7, 37.1) deaths per 1,000 person-years. The 3 most common causes of death were identical in both sexes: HIV-related causes, overdose, and other nonaccidental causes (e.g., respiratory disease, circulatory disease, or neoplasms). Compared with the age- and sex-matched British Columbia population from 2004, the standardized mortality ratios were 7.28 (95% CI: 6.50, 8.14) for men and 15.56 (95% CI: 13.31, 18.07) for women. In comparison, among the 606 participants who were considered lost to follow-up, there were 46 deaths, which were not included in the analysis because of censoring criteria, and the CMR in that sample was 15.9 (95% CI: 12.2, 20.7) deaths per 1,000 person-years. When stratified by sex, there were 19.6 (95% CI: 13.3, 29.0) deaths per 1,000 person-years among women and 13.7 (95% CI: 9.5, 19.7) deaths per 1,000 person-years among men. Causes of these 46 deaths included the following: 14 (30.4%) HIV-related causes, 10 (21.7%) other nonaccidental causes, 6 (13.0%) other accidental causes, 5 (10.9%) overdoses, 3 (6.5%) suicides, and 1 (2.2%) homicide; cause of death was unknown for 7 (15.2%). In the Kaplan-Meier analysis, there was no statistically significant difference between men and women in the cumulative survival probability (log-rank Pvalue = 0.27). As reflected in Table 2, there was also no statistically significant difference between the age-adjusted all-cause mortality rates for women and men observed over the study period (adjusted rate ratio = 1.04, 95% CI: 0.86, 1.25). However, female sex was significantly positively associated with rates of cause-specific mortality from homicide (adjusted rate ratio = 2.86,95% CI: 1.05, 7.83) and other nonaccidental causes (adjusted rate ratio = 1.67, 95% CI: 1.15, 2.42) and significantly negatively associated with rates of liver-related deaths (adjusted rate ratio = 0.33, 95% CI: 0.11, 0.98). Figure 2 depicts rates of death from the 3 most common causes among men and women, stratified by 4-year time intervals. The trends in the cause-specific mortality rates observed in the Figure were consistent with results from age-adjusted Poisson regression analyses. Specifically, overdose mortality rates significantly declined over time among both men (P =0.01) and women (P = 0.02). HIV-related mortality rates also significantly declined over time among men (P = 0.02) but remained stable among women (P = 0.75). The rates of death from other nonaccidental causes had nonsignificant trends among men (P = 0.11) and marginally significant increasing trends among women (P = 0.06). Predictors of all-cause mortality Overall, the median time elapsed between the last study visit and the date of death was 3.9 months (interquartile range, 2.0–6.1). Table 3 shows the results of univariable and multivariable extended Cox regression analyses in which we examined predictors of all-cause mortality. As shown, in multivariable analyses, age and HIV seropositivity remained independently and positively associated with time to all-cause mortality among both men and women (all P< 0.05). Cocaine injection at least once per day was independently associated with mortality only among women (adjusted hazard ratio = 1.67, 95% CI: 1.15, 2.42), whereas unstable housing was independently associated with mortality only among men (adjusted hazard ratio = 1.33, 95% CI: 1.05, 1.68). Enrollment in addiction treatment was protective against mortality only among men (adjusted hazard ratio = 0.66, 95% CI: 0.53, 0.83). DISCUSSION In the present 15-year cohort study, we found that the mortality rates were 7 and 16 times higher among men and women, respectively, who injected drugs in Vancouver compared with the sex- and age-matched general population in British Columbia. Although the leading causes of death were similar among male and female IDUs, including HIV-related causes, overdose, and other nonaccidental causes (e.g., circulatory disease, respiratory disease, and neoplasms), the age-adjusted rates of death from homicide and nonaccidental causes were higher among women. During the study period, overdose mortality rates significantly declined in both sexes. HIV-related mortality rates also significantly declined over time among men but remained stable among women. In multivariable analyses, age and HIV seropositivity were identified as independent predictors of all-cause mortality among both sexes. Other independent predictors included unstable housing among men only and cocaine injection at least once per day among women only. Enrollment in addiction treatment had a negative association with mortality among men only. Consistent with results from a recent meta-analysis (1), our results showed markedly elevated mortality among IDUs compared with the general population, and the excess mortality rate was twice as high in women as in men. Also, consistent with results from a previous study from our setting (24), our findings suggest that HIV infection plays a pivotal role in the excess mortality burden among IDUs in this setting. In addition, the present study findings point to important sex-based differences in the trends in the mortality burden related to HIV/acquired immunodeficiency syndrome. Specifically, among male IDUs, the HIV-related mortality rate significantly declined over time, which is congruent with literature reporting the expanded HAART coverage and associated decreases in mortality in British Columbia during the present study period (10, 11, 25). However, our results suggest that female IDUs are not benefiting from the HAART expansion to the same degree as male IDUs. In a previous study, Tapp et al. (26) reported lower access and adherence to HAART among female HIV-positive IDUs locally, which suggests that these women might be more entrenched in street-based activities, such as sex work, than their male counterparts and thereby more marginalized from health care. Accordingly, efforts are needed to address barriers to HIV care among female IDUs. The only drug-use pattern identified as an independent predictor of mortality was cocaine injection at least once per day among women. In our previous study in which we examined the relationship between drug use patterns and all-cause mortality in the same IDU cohort, daily cocaine injection was also found to be the only independent predictor of death among a sample of men and women (27). The present study serves to refine our understanding of this finding, demonstrating that the mortality burden attributable to daily cocaine injection was likely driven by female IDUs. At baseline, we found that a greater proportion of female IDUs were engaged in cocaine injection at least once per day than were male IDUs. Accordingly, more women than men might have developed various serious health consequences of intensive cocaine injection, including cardiovascular complications, neurological disorders, and infectious diseases (28–30). In addition, it has been demonstrated in many past studies that interrelationships exist among cocaine use, intimate partner violence, and other risks among women, which indicates that sex-related power dynamics exacerbate harms for cocaine-using women (31–34). Emergent neurobiological research further suggests that differences in brain organization and circulating hormones might render women more vulnerable to adverse consequences of cocaine than men (5, 35). Given the enormous challenges arising from cocaine use, a novel therapeutic option for cocaine-use disorder is urgently needed. Enrolment in addiction treatment was shown to be protective against death among men only. Taken together with the finding that a greater proportion of women than of men were engaged in crack cocaine or other cocaine use at least once per day at baseline in the present study, our results might reflect a lack of effective therapeutic options for these cocaine users in this setting and elsewhere (36), which might have served to diminish the association between addiction treatment and mortality among our sample of female IDUs. Although our findings suggest that existing addiction treatment modalities provide some mortality benefits, at least among male IDUs, it is notable that unstable housing independently predicted mortality among men, even after adjustment for enrollment in addiction treatment. In our previous work, we also found that unstable housing was independently associated with a higher mortality risk in this setting among a sample of IDUs that was not stratified by sex (37). The present study adds important evidence to the literature, demonstrating differential associations of housing instability with survival between male and female IDUs in this setting. The discrepancy might reflect that the mortality burden of social, structural, and environmental factors, including availability of addiction treatment and housing stability, could manifest itself in untreated stimulant addiction among female IDUs, whereas for men, such social, structural, and environmental factors contribute to mortality via more diverse pathways rather than through addiction to a particular substance. Future research should seek to unpack the complex relationships between mortality and such social, structural, and environmental factors. We also found that women were more likely than men to die from homicide. Previous literature has indicated that male-dominated local drug scenes render women vulnerable to violence (38). In this context, many female IDUs have cited the local supervised injection facility as an environment in which they take refuge from threats of violence (39). Therefore, improved harm reduction and other service points within and around the drug scene are recommended to enhance the accessibility of such services for women. Further, much of the violence experienced by female IDUs has been attributed to involvement in sex work (40, 41). Recent evidence suggests that structural changes, including efforts to decriminalize sex work, have the potential to reduce violence against women engaged in sex work (41). Our study has limitations. First, because the sample was not randomly selected, our findings might not be generalizable to other populations of IDUs. Second, the self-reported data might be affected by response biases. However, we note that self-reported data have been commonly used in studies involving IDUs and have been found to be valid (42). Third, the relationships between the explanatory variables and outcome assessed might be influenced by unmeasured confounding, although we sought to address this bias with multivariable adjustments that involved key predictors of survival. Fourth, although there could be potential bias related to the loss to follow-up, we note that such bias can be assessed in our study because we were able to identify mortality among those who were lost to follow-up via the linkage to the provincial Vital Statistics Agency database. Causes of death among those lost to follow-up were generally similar to those among the noncensored sample, which suggests that participants who dropped out of the study were unlikely to have considerably different mortality risks than those who were retained in the study. Nonetheless, given that the mortality rate among those lost to follow-up was lower than among those who remained in the sample, there exists the possibility of differential bias between covariates measured at the last recorded visit and mortality. However, because fewer than 10% of the deaths occurred among those lost to follow-up, we expect the magnitude of this bias to be small. Fifth, the reported mortality rates might be underestimated; deaths that occurred outside of the province were not recorded in the provincial registry. We were unable to ascertain detailed data on participants who migrated out of the province of British Columbia; however, there were only 27 (3.9%) women and 44 (2.9%) men who reported living outside of the province at their last study visit, and there was no significant difference between the sexes with respect to migration at the last study visit (Pearson's χ2 test P value = 0.498). Nonetheless, we cannot preclude the possibility that migration rates differed by mortality status or risks. Finally, approximately 7% of the deceased participants were recorded as dying from unknown causes. Consequently, we might have underestimated the true prevalence of some specific causes of death. In conclusion, the present study highlights persistently high mortality rates among IDUs in this setting, and the excess mortality burden was primarily attributable to HIV infection. Compared with men who injected drugs, women who injected drugs were at higher risk of HIV-related mortality and were more likely to die from homicide. Further, the only drug-use pattern associated with mortality was high-intensity cocaine injection among women only. These findings indicate a need for sex-specific interventions to reduce mortality among female IDUs in this setting.   ACKNOWLEDGMENTS Author affiliations: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, Vancouver, British Columbia, Canada (Kanna Hayashi, Huiru Dong, Michael-John Milloy, Julio S. G. Montaner, Evan Wood, Thomas Kerr); Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada (Kanna Hayashi, Michael-John Milloy, Julio S. G. Montaner, Evan Wood, Thomas Kerr); and Department of Epidemiology, School of Public Health, Brown University, Providence, Rhode Island (Brandon D. L. Marshall). The study was supported by the United States National Institutes of Health (grant U01DA038886 to the Vancouver Injection Drug Users Study and grant R01DA021525 to the AIDS Care Cohort to Evaluate Access to Survival Services). This research was undertaken, in part, thanks to funding from the Canada Research Chairs Program through a Tier 1 Canada Research Chair in Inner City Medicine, which supports E.W. K.H. is supported by the Canadian Institutes of Health Research New Investigator Award (grant MSH-141971). M.J.M. is supported in part by the United States National Institutes of Health (grant R01-DA021525). J.S.G.M. is supported with grants paid to his institution by the British Columbia Ministry of Health and by the United States National Institutes of Health (grant R01DA036307). J.S.G.M. has also received limited unrestricted funding paid to his institution from AbbVie Corporation (Pointe-Claire, Quebec, Canada), Bristol-Myers Squibb Canada (Montreal, Quebec, Canada), Gilead Sciences, Inc. (Foster City, California), Janssen, Inc. (Toronto, Ontario, Canada), Merck Canada, Inc. (Kirkland, Quebec, Canada), and ViiV Healthcare (Research Triangle Park, North Carolina). This work was presented in part as a poster at the 10th National Harm Reduction Conference, October 23–26, 2014, Baltimore, Maryland. The funding agencies had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication. Conflict of interest: none declared. REFERNCES 1. Mathers BM , Degenhardt L, Bucello Cet al. Mortality among people who inject drugs: a systematic review and meta-analysis. Bull World Health Organ . 2013;912:102–123. 2. Bargagli AM , Sperati A, Davoli Met al. Mortality among problem drug users in Rome: an 18-year follow-up study, 1980–97. Addiction . 2001;9610:1455–1463 3. Gjersing L , Bretteville-Jensen AL. Gender differences in mortality and risk factors in a 13-year cohort study of street-recruited injecting drug users. BMC Public Health . 2014;14:440. 4. Roberts A , Mathers B, Degenhardt Let al. Women Who Inject Drugs: a Review of Their Risks, Experiences and Needs . Sydney, Australia: National Drug and Alcohol Research Centre, University of NSW; 2010. 5. Fattore L , Altea S, Fratta W. Sex differences in drug addiction: a review of animal and human studies. Womens Health (Lond Engl) . 2008;41:51–65. 6. Volkow ND , Tomasi D, Wang G-Jet al. Reduced metabolism in brain “control networks” following cocaine-cues exposure in female cocaine abusers. PLoS One . 2011;62:e16573. 7. Des Jarlais DC , Feelemyer JP, Modi SNet al. Are females who inject drugs at higher risk for HIV infection than males who inject drugs: an international systematic review of high seroprevalence areas. Drug Alcohol Depend . 2012;124(1-2):95–107. 8. Shannon K , Kerr T, Allinott Set al. Social and structural violence and power relations in mitigating HIV risk of drug-using women in survival sex work. Soc Sci Med . 2008;664:911–9 9. Strathdee SA , Patrick DM, Currie SLet al. Needle exchange is not enough: lessons from the Vancouver injecting drug use study. AIDS . 1997;118:F59–F65. 10. Wood E , Kerr T, Marshall BDet al. Longitudinal community plasma HIV-1 RNA concentrations and incidence of HIV-1 among injecting drug users: prospective cohort study. BMJ . 2009;338:b1649. 11. Montaner JSG , Lima VD, Harrigan PRet al. Expansion of HAART coverage is associated with sustained decreases in HIV/AIDS morbidity, mortality and HIV transmission: the “HIV Treatment as Prevention” experience in a Canadian setting. PLoS One . 2014;92:e87872. 12. Kerr T , Small W, Buchner Cet al. Syringe sharing and HIV incidence among injection drug users and increased access to sterile syringes. Am J Public Health . 2010;1008:1449–1453. 13. Marshall BD , Milloy MJ, Wood Eet al. Reduction in overdose mortality after the opening of North America's first medically supervised safer injecting facility: a retrospective population-based study. Lancet . 2011;3779775:1429–1437. 14. Nosyk B , Marsh DC, Sun Het al. Trends in methadone maintenance treatment participation, retention, and compliance to dosing guidelines in British Columbia, Canada: 1996–2006. J Subst Abuse Treat . 2010;391:22–31. 15. Strathdee SA , Palepu A, Cornelisse PGAet al. Barriers to use of free antiretroviral therapy in injection drug users. JAMA . 1998;2806:547–549. 16. Copeland L , Budd J, Robertson JRet al. Changing patterns in causes of death in a cohort of injecting drug users, 1980–2001. Arch Intern Med . 2004;16411:1214–1220. 17. Miller CL , Kerr T, Strathdee SAet al. Factors associated with premature mortality among young injection drug users in Vancouver. Harm Reduct J . 2007;4:1. 18. British Columbia Vital Statistics Agency. Selected Vital Statistics and Health Status Indicators: One Hundred and Thirty-Third Annual Report 2004.  http://www2.gov.bc.ca/gov/content/vital-statistics/statistics-reports/annual-reports/2004. Published 2004. Accessed July 16, 2015. 19. Statistics Canada. July 1st population estimates by standard age groups. http://www.bcstats.gov.bc.ca/Files/d2526165-353b-4d39-ad85-2c0e3db7ed4d/Provinces-5-yearagesexpopulationtotals.xls. Updated September 27, 2012. Accessed January 13, 2014. 20. Statistics Canada. July 1st population estimates by standard age groups. http://www.bcstats.gov.bc.ca/Files/d2526165-353b-4d39-ad85-2c0e3db7ed4d/Provinces-5-yearagesexpopulationtotals.xls. Updated September 27, 2012. Accessed January 13, 2014. 21. Institute of Gender and Health at the Canadian Institutes of Health Research. What a Difference Sex and Gender Make . Vancouver, BC: Institute of Gender and Health at the Canadian Institutes of Health Research; 2012. 22. Kim C , Kerr T, Li Ket al. Unstable housing and hepatitis C incidence among injection drug users in a Canadian setting. BMC Public Health . 2009;9:270. 23. Milloy MJ , Kerr T, Buxton Jet al. Dose-response effect of incarceration events on nonadherence to HIV antiretroviral therapy among injection drug users. J Infect Dis . 2011;2039:1215–1221. 24. Lappalainen L , Hayashi K, Dong Het al. Ongoing impact of HIV infection on mortality among people who inject drugs despite free antiretroviral therapy. Addiction . 2015;1101:111–119. 25. Montaner JS , Lima VD, Barrios Ret al. Association of highly active antiretroviral therapy coverage, population viral load, and yearly new HIV diagnoses in British Columbia, Canada: a population-based study. Lancet . 2010;3769740:532–539. 26. Tapp C , Milloy MJ, Kerr Tet al. Female gender predicts lower access and adherence to antiretroviral therapy in a setting of free healthcare. BMC Infect Dis . 2011;11:86. 27.  Hayden A , Hayashi K, Dong Het al. The impact of drug use patterns on mortality among polysubstance users in a Canadian setting: a prospective cohort study. BMC Public Health . 2014;14:1153. 28. Brody SL , Slovis CM, Wrenn KD. Cocaine-related medical problems: consecutive series of 233 patients. Am J Med . 1990;884:325–331. 29. Buchanan D , Tooze JA, Shaw Set al. Demographic, HIV risk behavior, and health status characteristics of “crack” cocaine injectors compared to other injection drug users in three New England cities. Drug Alcohol Depend . 2006;813:221–229. 30. Tyndall MW , Currie S, Spittal Pet al. Intensive injection cocaine use as the primary risk factor in the Vancouver HIV-1 epidemic. AIDS . 2003;176:887–893. 31. Gilbert L , El-Bassel N, Chang Met al. Substance use and partner violence among urban women seeking emergency care. Psychol Addict Behav . 2012;262:226–235. 32. Shannon K , Rusch M, Morgan Ret al. HIV and HCV prevalence and gender-specific risk profiles of crack cocaine smokers and dual users of injection drugs. Subst Use Misuse . 2008;43(3-4):521–534. 33. El-Bassel N , Gilbert L, Wu Eet al. HIV and intimate partner violence among methadone-maintained women in New York City. Soc Sci Med . 2005;611:171–183. 34. Joe GW , Simpson DD. HIV risks, gender, and cocaine use among opiate users. Drug Alcohol Depend . 1995;371:23–28. 35. Andersen ML , Sawyer EK, Howell LL. Contributions of neuroimaging to understanding sex differences in cocaine abuse. Exp Clin Psychopharmacol . 2012;201:2–15. 36. Fischer B , Cruz MS, Bastos FIet al. Crack across the Americas—a massive problem in continued search of viable answers: exemplary views from the North (Canada) and the South (Brazil). Int J Drug Policy . 2013;246:631–633. 37. Zivanovic R , Milloy MJ, Hayashi Ket al. Impact of unstable housing on all-cause mortality among persons who inject drugs. BMC Public Health . 2015;15:106. 38. McNeil R , Shannon K, Shaver Let al. Negotiating place and gendered violence in Canada's largest open drug scene. Int J Drug Policy . 2014;253:608–615. 39. Fairbairn N , Small W, Shannon Ket al. Seeking refuge from violence in street-based drug scenes: women's experiences in North America's first supervised injection facility. Soc Sci Med . 2008;675:817–823. 40. Azim T , Chowdhury EI, Reza Met al. Vulnerability to HIV infection among sex worker and non-sex worker female injecting drug users in Dhaka, Bangladesh: evidence from the baseline survey of a cohort study. Harm Reduct J . 2006;3:33. 41. Deering KN , Amin A, Shoveller Jet al. A systematic review of the correlates of violence against sex workers. Am J Public Health . 2014;1045:e42–e54. 42. Darke S . Self-report among injecting drug users: a review. Drug Alcohol Depend . 1998;513:253–263.  Figure 1. Flow chart showing the way the analytical sample (n = 2,317) was determined, Vancouver Injection Drug Users Study (VIDUS) and AIDS Care Cohort to Evaluate Exposure to Survival Services (ACCESS), Vancouver, British Columbia, Canada, 1996–2011.                 Figure 2. Sex-specific mortality rates per 1,000 person-years for 3 common causes of death among injection drug users (n = 2,317), Vancouver Injection Drug Users Study and AIDS Care Cohort to Evaluate Exposure to Survival Services, Vancouver, British Columbia, Canada, 1996–2011. A) Mortality rates among men (n = 1,523). B) Mortality rates among women (n = 794).     

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.52383.1-0355767/manifest

Comment

Related Items