OBJECTIVE—Polychlorinated biphenyls (PCBs) are persistent pollutants that are ubiquitous in the food chain; detectable amounts are in the blood of nearly everyone. 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 reported among subjects with diabetes, suggesting that PCB levels could be similarly elevated. To test this hypothesis, we examined a group of pregnant women 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 whom 44 had diabetes (primarily type 1) and 2,201 were control subjects.
RESULTS—The adjusted mean serum level of PCBs among the subjects with diabetes was 30% higher than in the control subjects (P = 0.0002), and the relationship of PCB level to adjusted odds of diabetes was linear.
CONCLUSIONS—The possibility exists that PCBs and diabetes are causality related; alternatively, the pharmacokinetics of PCBs could be altered among patients with diabetes. At any event, if the association is replicated in other studies, increased serum levels of PCBs in subjects with diabetes or their offspring may put them at increased risk of PCB-induced changes in thyroid metabolism or neurodevelopment.
- CPP, Collaborative Perinatal Project
- CV, coefficient of variation
- PCB, polychlorinated biphenyl
- TCDD, tetrachlorodibenzo-p-dioxin
Address correspondence and reprint requests to Dr. M.P. Longnecker, Medical Research Officer, NIEHS EB, P.O. Box 12233 MD A3–05, Research Triangle Park, NC 27709. E-mail:.
Received for publication 5 October 2000 and accepted in revised form 27 February 2001.
J.W.B. holds stock in Watson Pharmaceuticals, Merck, Johnson and Johnson, and Cardinal Health.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.