Lactational exposure to polychlorinated biphenyls is higher in overweight /obese women and associated with altered infant growth trajectory: A pilot study

Abstract Background Infant exposure to environmental chemicals, such as polychlorinated biphenyls (PCBs), may contribute to developmental programming of long-term metabolic disease risk. PCBs persist given their lipophilicity and long half-lives, allowing them to bio-accumulate in adipose tissue. These compounds can then be excreted into maternal milk resulting in infant exposure. Objective To determine the level of PCBs in milk from mothers with pre-pregnancy overweight and obese (OW/OB) versus normal weight status (NW) and evaluate the association of milk PCB levels with infant growth over the first 6 months of life. Methods A pilot study of a subset of milk samples from mothers with NW (pre-pregnancy body mass index (BMI) Results Total milk fat content did not differ by maternal weight status (p=0.88). Milk from mothers with OW/OB had significantly higher PCB sum (p=0.02) and PCB 138+163 (p=0.03). PCB 132+153 (β -0.0008, p=0.0218), PCB 180 (β -0.0010, p=0.0279), and PCB sum (β -0.0006, p=0.0138) were negatively associated with HCA Z-score growth to 6 months. PCB 180 was negatively associated with infant WFA (β -0.0015, p=0.0058) and WFL Z-score (β -0.0016, p=0.0263) to 6 months. There were no associations of PCB sum content with WFL, LFA, WFL Z-score over the first 6 months of life. Conclusions Maternal overweight and obesity are associated with higher levels of total PCB congeners (132, 138, 153, 163, 180) in human milk. PCB congeners have negative associations with infant head circumference and weight trajectory over the first 6 months of life.