Phthalate Metabolites and Skinfold Thickness in 4-Year-Old Boys and Girls
Endocrine disruptors, including phthalates, can have sexually dimorphic effects during development. Evidence from animal models suggests an association between prenatal phthalate exposure and body fat distribution, yet epidemiological work examining sex-specific relationships is limited. The aim of this study was to determine whether first-trimester maternal urinary phthalate metabolite concentrations were associated with a child’s skinfold thickness at age four, and if this association differs by sex. Phthalate concentrations were measured in first-trimester urine samples from pregnant women enrolled in TIDES. Child subscapular and triceps skinfold thickness (mm) were used to create an overall summary variable. We used multivariable linear regression, stratified by sex, to assess the association between phthalate metabolite concentrations and skinfold thickness. Skinfold thickness was greater in girls (summary variable: 16.8 vs 14.8 mm, p<0.001). In fully adjusted sex-specific models, higher skinfold thickness was associated with slightly higher mCPP (p=0.03) in boys. Phthalate concentrations were not associated with skinfold thickness in females in either unadjusted or adjusted models. Previous suggestions that early pregnancy phthalate exposure is associated with early childhood fat distribution were generally not observed when we examined skinfold thickness for 4-year-old children.