A Cohort Study of Traffic-Related Air Pollution Impacts on Birth Outcomes

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A Cohort Study of Traffic-Related Air Pollution Impacts on Birth Outcomes Brauer, Michael (Of University of British Columbia); Lencar, Cornel; Tamburic, Lillian; Koehoorn, Mieke, 1966-; Demers, Paul; Karr, Catherine

Abstract

BACKGROUND: Evidence suggests that air pollution exposure adversely affects pregnancy outcomes. Few studies have examined individual-level intraurban exposure contrasts. OBJECTIVES: We evaluated the impacts of air pollution on small for gestational age (SGA) birth weight, low full-term birth weight (LBW), and preterm birth using spatiotemporal exposure metrics. METHODS: With linked administrative data, we identified 70,249 singleton births (1999–2002) with complete covariate data (sex, ethnicity, parity, birth month and year, income, education) and maternal residential history in Vancouver, British Columbia, Canada. We estimated residential exposures by month of pregnancy using nearest and inverse-distance weighting (IDW) of study area monitors [carbon monoxide, nitrogen dioxide, nitric oxide, ozone, sulfur dioxide, and particulate matter < 2.5 (PM₂.₅) or < 10 (PM₁₀) μm in aerodynamic diameter], temporally adjusted land use regression (LUR) models (NO, NO₂, PM₂.₅, black carbon), and proximity to major roads. Using logistic regression, we estimated the risk of mean (entire pregnancy, first and last month of pregnancy, first and last 3 months) air pollution concentrations on SGA (< 10th percentile), term LBW (< 2,500 g), and preterm birth. RESULTS: Residence within 50 m of highways was associated with a 26% increase in SGA [95% confidence interval (CI), 1.07–1.49] and an 11% (95% CI, 1.01–1.23) increase in LBW. Exposure to all air pollutants except O₃ was associated with SGA, with similar odds ratios (ORs) for LUR and monitoring estimates (e.g., LUR: OR = 1.02; 95% CI, 1.00–1.04; IDW: OR = 1.05; 95% CI, 1.03–1.08 per 10-μg/m³ increase in NO). For preterm births, associations were observed with PM₂.₅ for births < 37 weeks gestation (and for other pollutants at < 30 weeks). No consistent patterns suggested exposure windows of greater relevance. CONCLUSION: Associations between traffic-related air pollution and birth outcomes were observed in a population-based cohort with relatively low ambient air pollution exposure.

Item Metadata

Title	A Cohort Study of Traffic-Related Air Pollution Impacts on Birth Outcomes
Creator	Brauer, Michael (Of University of British Columbia); Lencar, Cornel; Tamburic, Lillian; Koehoorn, Mieke, 1966-; Demers, Paul; Karr, Catherine
Contributor	University of British Columbia. Centre for Health Services and Policy Research
Date Issued	2008-05
Description	BACKGROUND: Evidence suggests that air pollution exposure adversely affects pregnancy outcomes. Few studies have examined individual-level intraurban exposure contrasts. OBJECTIVES: We evaluated the impacts of air pollution on small for gestational age (SGA) birth weight, low full-term birth weight (LBW), and preterm birth using spatiotemporal exposure metrics. METHODS: With linked administrative data, we identified 70,249 singleton births (1999–2002) with complete covariate data (sex, ethnicity, parity, birth month and year, income, education) and maternal residential history in Vancouver, British Columbia, Canada. We estimated residential exposures by month of pregnancy using nearest and inverse-distance weighting (IDW) of study area monitors [carbon monoxide, nitrogen dioxide, nitric oxide, ozone, sulfur dioxide, and particulate matter < 2.5 (PM₂.₅) or < 10 (PM₁₀) μm in aerodynamic diameter], temporally adjusted land use regression (LUR) models (NO, NO₂, PM₂.₅, black carbon), and proximity to major roads. Using logistic regression, we estimated the risk of mean (entire pregnancy, first and last month of pregnancy, first and last 3 months) air pollution concentrations on SGA (< 10th percentile), term LBW (< 2,500 g), and preterm birth. RESULTS: Residence within 50 m of highways was associated with a 26% increase in SGA [95% confidence interval (CI), 1.07–1.49] and an 11% (95% CI, 1.01–1.23) increase in LBW. Exposure to all air pollutants except O₃ was associated with SGA, with similar odds ratios (ORs) for LUR and monitoring estimates (e.g., LUR: OR = 1.02; 95% CI, 1.00–1.04; IDW: OR = 1.05; 95% CI, 1.03–1.08 per 10-μg/m³ increase in NO). For preterm births, associations were observed with PM₂.₅ for births < 37 weeks gestation (and for other pollutants at < 30 weeks). No consistent patterns suggested exposure windows of greater relevance. CONCLUSION: Associations between traffic-related air pollution and birth outcomes were observed in a population-based cohort with relatively low ambient air pollution exposure.
Subject	Air pollution; Birth weight; Carbon black; Carbon monoxide; Nitrogen dioxide; Nitric oxide; Particulate matter; Pregnancy outcome; Preterm birth; Soot; Sulfur dioxide; Vehicle emissions
Genre	Article
Type	Text
Language	eng
Date Available	2015-10-24
Provider	Vancouver : University of British Columbia Library
Rights	Attribution-NonCommercial-NoDerivs 2.5 Canada
DOI	10.14288/1.0074698
URI	http://hdl.handle.net/2429/54818
Affiliation	Environmental Health (SOEH), School of; Health Care and Epidemiology, Department of; Non UBC; Medicine, Faculty of; Population and Public Health (SPPH), School of
Citation	Brauer M, Lencar C, Tamburic L, Koehoorn M, Demers P, Karr C. Environ Health Perspect. 2008 May;116(5):680-6.
Publisher DOI	10.1289/ehp.10952.
Peer Review Status	Reviewed
Scholarly Level	Faculty
Copyright Holder	Environmental Health Perspectives
Rights URI	http://creativecommons.org/licenses/by-nc-nd/2.5/ca/
Aggregated Source Repository	DSpace

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