Associations Between Ambient Air Pollutant Concentrations and Birth Weight A Quantile Regression Analysis

• Type of Material: Article
• Authors: Matthew Strickland, Emory University; Ying Lin, Emory University; Lyndsey Darrow, Emory University; Joshua L. Warren, Yale University; James A. Mulholland, Georgia Institute of Technology; Howard Chang, Emory University
• Language: English
• Date: 2019-09-01
• Publisher: Lippincott Williams & Wilkins
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2019 Wolters Kluwer Health, Inc. All rights reserved.
• License: Creative Commons Attribution-NonCommercial 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1097/EDE.0000000000001038
• Title of Journal or Parent Work: Epidemiology
• Volume: 30
• Issue: 5
• Start Page: 624
• End Page: 632
• Grant/Funding Information: This work was also supported by grants from the National Center for Advancing Translational Sciences of the National Institutes of Health under Award Numbers UL1TR000454, UL1TR001863, and KL2TR001862.; The results reported herein are from an alternative analysis (quantile regression) for Specific Aim 3 for Project 3 of United States Environmental Protection Agency center grant R834799.
• Keywords: Public, Environmental & Occupational Health; Science & Technology; Pregnancy; Life Sciences & Biomedicine; Fine particulate matter; Exposure; Preterm birth; Residential mobility; Critical windows; Air pollution; Quantile regression; Birth weight
• Research Categories: Health Sciences, Occupational Health and Safety; Environmental Sciences; Biology, Biostatistics; Health Sciences, Public Health; Biology, Bioinformatics

Abstract

INTRODUCTION: We investigated the extent to which associations of ambient air pollutant concentrations and birth weight varied across birth weight quantiles. METHODS: We analyzed singleton births ≥27 weeks gestation from 20-county metropolitan Atlanta with conception dates between 1 January 2002 and 28 February 2006 (N=273,711). Trimester-specific and total pregnancy average concentrations for 10 pollutants, obtained from ground observations that were interpolated using 12-km Community Multiscale Air Quality model outputs, were assigned using maternal residence at delivery. We estimated associations between interquartile range width (IQRw) increases in pollutant concentrations and changes in birth weight using quantile regression. RESULTS: Gestational age-adjusted associations were of greater magnitude at higher percentiles of the birth weight distribution. Pollutants with large vehicle source contributions (carbon monoxide, nitrogen dioxide, PM2.5 elemental carbon, and total PM2.5 mass), as well as PM2.5 sulfate and PM2.5 ammonium, were associated with birth weight decreases for the higher birth weight percentiles. For example, whereas the decrease in mean birthweight per IQRw increase in PM2.5 averaged over pregnancy was −7.8g (95% CI: −13.6g, - 2.0g), the quantile-specific associations were: 10th percentile −2.4g (−11.5g, 6.7g); 50th percentile −8.9g (−15.7g, −2.0g); and 90th percentile −19.3g (−30.6g, −7.9g). Associations for the intermediate and high birth weight quantiles were not sensitive to gestational age adjustment. For some pollutants we saw associations at the lowest quantile (10th percentile) when not adjusting for gestational age. CONCLUSIONS: Associations between air pollution and reduced birth weight were of greater magnitude for newborns at relatively heavy birth weights.