Exposure to Metal Mixtures and Childhood Adiposity: An Examination of Periods of Heightened Susceptibility Between Gestation and Late Childhood.

Introduction: Childhood obesity is a public health concern. Studies have investigated the effects of metal mixtures on childhood obesity but none have identified periods of heightened susceptibility of exposure. We identified the periods by investigating the association of metal mixture, measured at four time points, with adiposity.

Materials and methods: Using data from the Maternal-Infant Research on Environmental Chemicals Research Platform, we included 234 child-parent pairs. We measured whole blood metal concentrations during the first and third trimesters, early and late childhood. Outcomes were late childhood body mass index z-score (zBMI), body fat percentage (%BF) and waist circumference z-score (zWC). We used treed distributed lag mixture models (TDLMM) to investigate associations between metal mixture and adiposity. We also investigated associations using linear regression and conducted sex-specific analysis.

Results: Among females, arsenic was positively associated with zBMI and zWC. Regression results show that each doubling in third trimester arsenic concentrations was associated with 0.16 (95% CI: 0.02, 0.31) and 0.13 (95% CI: 0.01, 0.25) increase in zBMI and zWC, respectively. TDLMM results were similar but attenuated. We also observed negative associations between third trimester cadmium and zWC, null associations between other metals and adiposity and among males and no metal interactions.

Conclusion: Third trimester is a period of heightened susceptibility to obesogenic effects of arsenic exposure in females.