Prenatal Environment and Adult Body Composition

Abstract

Past research suggests intrauterine exposure to polychlorinated biphenyls (PCB) and dichlorodiphenyl dichloroethylene (DDE) decreases birth weight and youth height and weight. However, effects of PCB and DDE on adult body size and fatness are unknown, particularly when physical activity (PA) is considered. PURPOSE: To examine the effect of birth weight and intrauterine exposure to PCB and DDE on female adult weight, body mass index (BMI), and percent body fat (%fat), and to determine if PA modifies these relationships. METHODS: Our sample included 71 female offspring from the Michigan fish-eater cohort (age =39.9±7.9 yr), with previously reported birth weights. Exposure to PCB and DDE were extrapolated backwards to date of birth from maternal serum values. A portable stadiometer and scale measured adult height and weight. BMI was calculated (kg/m2), as were % fat (skinfolds) and weekly PA (7-day recall). A median split denned LOW and HIGH active women (< and > 425 min PA/wk, respectively). Because adult data were skewed, Spearman correlations were used to analyze relationships between perinatal and adult variables. Partial correlations controlled for maternal BMI. RESULTS: Mean weight, BMI, and %fat were 74.9 ± 17.8 kg, 26.6 ±5.7 kg/m2, and 26.6 ± 6.6%, respectively. No significant correlations existed between adult body measures and prenatal PCB or DDE exposure. Within the LOW active group, birth weight was related to adult weight (r= 0.48, p=0.003) and %fat (r=0.34, p=0.048), and approached significance with BMI (r=0.32, p=0.060). These relationships did not exist for HIGH active women. After controlling for maternal BMI, birth weight was still significantly related to adult weight (r=0.52, p=0.002), BMI (r=0.36, p=0.046) and %fat (r=0.39, p=0.029) within the LOW, but not HIGH group. Compared to HIGH active women, LOW active women had significantly larger mean BMI (28.0 ± 6.6 v 25.2 ± 4.0 kg/m2) and greater %fat (28.2 ± 6.6 v 25.2 ± 6.6%, p<0.05). CONCLUSIONS: Prenatal PCB and DDE exposure are not related to female adult body size and fatness. After adjustment for confounding by maternal size, PA modified relationships between birth weight and adult weight and fatness, such that they only exist for low active women. Funded by the Agency for Toxic Substances and Disease Registry.