Detecting Associations between Early-Life DDT Exposures and Childhood Growth Patterns: A Novel Statistical Approach

It has been hypothesised that environmental exposures at key development periods such as in utero play a role in childhood growth and obesity. To investigate whether in utero exposure to endocrine-disrupting chemicals, dichlorodiphenyltrichloroethane (DDT) and its metabolite, dichlorodiphenyldichloroethane (DDE), is associated with childhood physical growth, we took a novel statistical approach to analyse data from the CHAMACOS cohort study. To model heterogeneity in the growth patterns, the authors used a finite mixture model in combination with a data transformation to characterise body mass index (BMI) with four groups and estimated the association between exposure and group membership. In boys, higher maternal concentrations of DDT and DDE during pregnancy are associated with a BMI growth pattern that is stable until about age five followed by increased growth through age nine. In contrast, higher maternal DDT exposure during pregnancy is associated with a flat, relatively stable growth pattern in girls. The authors concluded that the findings from this study suggests that in utero exposure to DDT and DDE may be associated with childhood BMI growth patterns, not just BMI level, and both the magnitude of exposure and sex may impact the relationship.

Authors: Heggeseth B, Harley K, Warner M, Jewell N, Eskenazi B. ;Full Source: PLoS One. 2015 Jun 30;10(6):e0131443. doi: 10.1371/journal.pone.0131443. eCollection 2015. ;