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

Background: Previous research observed links between prenatal air pollution and risk of childhood obesity but the timing of the exposure is understudied.

Aim: We examined prenatal particulate matter (PM, PM) exposure and child anthropometry.

Materials & Methods: 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.

Results: 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).

Conclusion: Even at low levels of air pollution, prenatal PM exposure was associated with higher zBMI in childhood.