Exposure to Environmental Chemicals during Pregnancy and Fetal Markers of Metabolic Dysfunction

Abstract

Obesity and type 2 diabetes are on the rise and in-utero exposure to environmental contaminants is a suspected factor. The Maternal-Infant Research on Environmental Chemicals Study (MIREC) recruited 2001 women during the first trimester of pregnancy from 10 Canadian sites. The present study was designed to examine associations between exposure to environmental chemicals during early pregnancy and markers of fetal metabolic dysfunction. Environmental contaminants, including metals, phthalates and bisphenol A, were measured in maternal blood or urine. Leptin and adioponectin levels were measured in cord blood and served as markers of metabolic dysfunction. Logistic regression models, adjusted for maternal BMI, ethnicity and maternal age, were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between environmental chemicals and fetal adiponectin and leptin levels. Effect modification by infant sex was also assessed. There were 1363 women who had a first trimester blood or urine sample and a cord blood sample. Leptin levels were significantly higher in females than males. Cadmium exposure among males was associated with significantly increased odds of elevated leptin (OR=5.58 95% CI: 1.58 to 19.68). A positive association between MEP phthalate levels and elevated leptin levels was also observed. No significant associations were found between environmental chemicals and cord blood adiponectin levels. The effects of prenatal exposure to certain environmental chemicals on cord blood leptin levels may be operating in a sex-dependent manner. Long-term implications for metabolic status and risk of obesity and type 2 diabetes should be investigated further.