Prenatal ozone exposure is associated with children overweight and obesity: Evidence from the Shanghai Maternal-Child Pairs Cohort.

Prenatal ozone (O) exposure may disrupt normal offspring growth. However, epidemiological evidence that prenatal O exposure affects the physical development of offspring early in life is far from adequate. A total of 4909 maternal-child pairs from the Shanghai Maternal-Child Pairs Cohort were included. A high-resolution random forest model was utilized to evaluate prenatal exposure levels of O based on the home addresses of pregnant women. Group-based trajectory and mixed-effects models were used to assess associations between prenatal O exposure and physical parameters. Each 10 μg/m³ increase in O concentration was associated with 0.084, 0.048, and 0.082-unit increases in body mass index (BMI) for age Z score (BAZ), weight for age Z score (WAZ), and weight for length Z score (WLZ), respectively. Specifically, a 10 μg/m³ increase in O concentration was linked to a 1.208-fold and 1.209-fold increase in the elevated-increasing group for the BAZ and WLZ trajectories, respectively. Moreover, each 10 μg/m³ increases in prenatal O was associated with a 1.396-fold and 0.786-fold increase in the risk of BAZ- and length for age Z score (LAZ)-accelerated growth, respectively. Furthermore, a 10 μg/m³ increase in prenatal O was linked to a 1.355-fold increase in the risk of overweight and obesity (OAO). Our study revealed that prenatal O exposure is associated with accelerated BMI gain or decelerated body length gain in the early life of children. Prenatal O may also increase the risk of OAO in children for the first two years.