Polychlorinated biphenyl serum levels in pregnant subjects with diabetes

OBJECTIVE - Polychlorinated biphenyls (PCBs) are persistent pollutants that are ubiquitous in the food chain; detectable amounts are in the blood of n early every one. Their effect on humans at background levels of exposure is an area of active investigation. Increased blood levels of dioxin (2,3,7,8 -tetrachlorodibenzo-p-dioxin), a PCB-like compound. have recently been repo rted among subjects with diabetes, suggesting that PCB levels could be simi larly elevated. To test this hypothesis, we examined a group of pregnant wo men whose serum PCB levels had been measured and whose diabetes status had been previously recorded. RESEARCH DESIGN AND METHODS - Using stored serum from a large birth cohort study, we conducted a cross-sectional study of 2,245 pregnant women, of who m 44 had diabetes (primarily type 1) and 2,201 were control subjects. RESULTS - The adjusted mean serum level of PCBs among, the subjects with di abetes was 30% higher than in the control subjects (P = 0.0002), and the re lationship of PCB level to adjusted odds of diabetes was linear. CONCLUSIONS - The possibility exists that PCBs and diabetes are causality r elated; alternatively, the pharmacokinetics of PCBs could be altered among patients with diabetes. At any event, if the association is replicated in o ther studies, increased serum levels of PCBs in subjects with diabetes or t heir offspring may put them at increased risk of PCB-induced changes in thy roid metabolism or neurodevelopment.