Background: Experimental models suggest that exposure to bisphenol A (BPA) in early life promotes excess adiposity, but it is unclear whether BPA exposure in human populations plays a role in childhood obesity. The objective of this study was to investigate the relationship between childhood exposure to BPA and excess body weight from human epidemiological studies.
Methods: Eligible studies were identified by systematic searches of Pubmed, Embase, Cochrane and Toxline databases, until 15th May 2015. There were no language restrictions and reference lists of relevant publications were also searched. Longitudinal cohort, cross-sectional and case-control studies were included if they reported urinary BPA concentrations in children. The primary outcome measures were age-and-sex-adjusted BMI percentile of ≥ 85th percentile for overweight and ≥ 95th percentile for obesity. High vs low dose analyses were used to calculate the pooled ORs, by comparing the odds of being overweight and obese for children in the highest vs lowest BPA exposure categories for each study. Linear dose response analyses were then preformed for exposure in school aged children using generalised least square trend estimation.
Results: Seven studies published between 2009 and 2014 were included, involving 4897 children worldwide. For children in the highest BPA exposure category the pooled OR for child overweight was 1.38 (95% CI 1.16 to 1.63, P < 0.0001) and child obesity was 1.56 (95% CI 1.26 to 1.92, P < 0.0001); compared to those with the lowest levels of exposure. Dose-response analysis found that for each 1 µg/L increase in child urinary BPA concentration, the pooled OR for child obesity increased by 4% (OR=1.04; 95% CI 1.01 to 1.07, p = 0.003).
Conclusion: BPA exposure is associated with a significant increased odds of overweight and obesity, providing a compelling argument that BPA promotes excess body weight and contributes to obesity in human children.