Prenatal exposure to particulates and anthropometry through 9 years of age in a birth cohort

Previous research observed links between prenatal air pollution and risk of childhood obesity but the timing of the exposure is understudied. We examined prenatal particulate matter (PM , PM ) exposure and child anthropometry. Children's body mass index z-scores (zBMI) at 0-3 (N = 4370) and 7-9 (n = 1191) years were derived from reported anthropometry at paediatric visits. We ran linear mixed models for six windows, adjusting for maternal, child, and neighbourhood factors. PM exposure across pregnancy and at multiple windows was associated with higher zBMI in both early and middle childhood. For instance, one interquartile range increase in PM exposure during the first 2 weeks of pregnancy was associated with higher zBMI at 0-3 (0.05, 95% CI: 0.01, 0.10) and 7-9 (0.14, 95% CI: 0.02, 0.23). PM exposure during the final 2 weeks of gestation was associated with higher zBMI at 7-9 years (B: 0.12, 95% CI: 0.04, 0.22). Even at low levels of air pollution, prenatal PM exposure was associated with higher zBMI in childhood.