Poverty and InequalitySexual and Reproductive HealthFamily, Maternal & Child HealthMethodology

Individual and Joint Effects of Early-Life Ambient PM2.5 Exposure and Maternal Pre-Pregnancy Obesity on Childhood Overweight or Obesity

TitleIndividual and Joint Effects of Early-Life Ambient PM2.5 Exposure and Maternal Pre-Pregnancy Obesity on Childhood Overweight or Obesity
Publication TypeJournal Article
Year of Publication2016
AuthorsMao, G, Nachman, RM, Sun, Q, Zhang, X, Koehler, K, Chen, Z, Hong, X, Wang, G, Caruso, D, Zong, G, Pearson, C, Ji, H, Biswal, S, Zuckerman, B, Wills-Karp, M, Wang, X
JournalEnviron Health Perspect
Date PublishedSep 16
ISBN Number1552-9924 (Electronic)0091-6765 (Linking)
Accession Number27633937

BACKGROUND: Although previous studies suggest that exposure to traffic-related pollution during childhood increases risk of childhood overweight or obesity (COWO), the role of early-life exposure to fine particulate matter (aerodynamic diameter <2.5 micrometers, PM2.5) and its joint effect with mother's pre-pregnancy body mass index (MPBMI) on COWO remain unclear. OBJECTIVES: The present study was conducted to examine the individual and joint effects of ambient PM2.5 exposures and MPBMI on the risk of COWO. METHODS: We estimated exposures to ambient PM2.5 in utero and during the first 2 years of life (F2YL), determined with data from EPA's Air Quality System matched to residential address, in 1446 mother-infant pairs, recruited at birth from 1998 and followed-up prospectively through 2012 at the Boston Medical Center in Massachusetts. We quantified the individual and joint effects of PM2.5 exposures with MPBMI on COWO, defined as child's age- and sex-specific BMI z-score>/=85th percentile at last well-child care visit between age 2 and 9 years. Additivity was assessed by estimating reduced excess risk due to interaction. RESULTS: Comparing the highest and lowest quartiles of PM2.5, the adjusted RR (95% CIs) of COWO were 1.3(1.1, 1.5), 1.2(1.0, 1.4), 1.2(1.0, 1.4), 1.3(1.1, 1.6), 1.3(1.1, 1.5) and 1.3(1.1, 1.5) during preconception, 1st, 2nd and 3rd trimester, entire period of pregnancy, and F2YL, respectively. Spline regression showed dose-response relationship between PM2.5 levels and COWO after a threshold near the median exposure (10.46 mug/m3 - 10.89 mug/m3). Compared to their counterparts, children of obese mothers exposed to high PM2.5 had the highest risk of COWO (RR>/=2.0, RERI not significant). CONCLUSIONS: In this study, we observed that early-life PM2.5 exposures may play an important role in the early-life origins of COWO and may increase risk of COWO in children of mothers who were overweight or obese before pregnancy beyond the risk due to MPBMI alone. Our findings underscore the clinical and public health policy relevance of early-life PM2.5 exposures.