Associations of prenatal exposure to bisphenols with BMI growth trajectories in offspring within the first two years: evidence from a birth cohort study in China.

Background: Prenatal bisphenol exposure has been reported to be associated with lower birth weight and obesity-related indicators in early childhood. These findings warrant an investigation of the relationship between prenatal bisphenol exposure and the dynamic growth of offspring. This study aimed to evaluate the relationship of maternal bisphenol concentration in urine with the body mass index (BMI) growth trajectory of children aged up to two years and to identify the critical exposure periods.

Methods: A total of 826 mother-offspring pairs were recruited from Wuhan Children's Hospital between November 2013 and March 2015. Maternal urine samples collected during the first, second, and third trimesters were analyzed for bisphenol A (BPA), bisphenol S, and bisphenol F (BPF) concentrations. Measurements of length and weight were taken at 0, 1, 3, 6, 8, 12, 18, and 24 months. Children's BMI was standardized using the World Health Organization reference, and group-based trajectory modeling was used to identify BMI growth trajectories. The associations between prenatal bisphenol exposure and BMI growth trajectory patterns were assessed using multinomial logistic regression models.

Results: The BMI growth trajectories of the 826 children were categorized into four patterns: low-stable (n = 134, 16.2%), low-increasing (n = 142, 17.2%), moderate-stable (n = 350, 42.4%), and moderate-increasing (n = 200, 24.2%). After adjusting for potential confounders, we observed that prenatal exposure to BPA during the second trimester [odds ratio (OR) = 2.20, 95% confidence interval (CI) = 1.09-4.43] and BPF during the third trimester (OR = 3.28, 95% CI = 1.55-6.95) at the highest quartile concentration were associated with an increased likelihood of the low-increasing BMI trajectory. Furthermore, in the subgroup analysis by infant sex, the positive association between the highest quartile of prenatal average urinary BPF concentration during the whole pregnancy and the low-increasing BMI trajectory was found only in girls (OR = 2.82, 95% CI = 1.04-7.68).

Conclusion: Our study findings suggest that prenatal exposure to BPA and BPF (a commonly used substitute for BPA) is associated with BMI growth trajectories in offspring during the first two years, increasing the likelihood of the low-increasing pattern. Video Abstract (MP4 120033 kb).