Abstract P009: Dietary Exposure to Polychlorinated Biphenyls and Incidence of Myocardial Infarction in Men - A Population-Based Prospective Cohort Study

Abstract

Introduction: Fish consumption may promote cardiovascular health. The role of major food contaminants present in fish, such as polychlorinated biphenyls (PCBs) is, however, largely unexplored. Experimental studies indicate that PCBs cause endothelial cell dysfunction, hyperlipidemia and hypertension and cross-sectional associations have been observed between PCB-biomarkers and several intermediate risk factors for cardiovascular disease. PCBs accumulate and magnify in the food chain and fatty fish is a dominating source of exposure in populations with a relatively high fish intake. We assessed the hypothesis that dietary PCB exposure is associated with increased risk of myocardial infarction (MI) and that the exposure may mask a protective association with marine omega-3 fish fatty acids intake. Methods: Validated food frequency questionnaire-based estimates of dietary PCB exposure was obtained at baseline (1997) in 36,759 men from the population-based Cohort of Swedish Men, free of cancer, cardiovascular disease and diabetes. The estimated dietary PCB exposure was based on the food concentrations of PCB congener 153 at the time of baseline. PCB-153 is the most abundant congener in food and an excellent indicator for total PCB in food and in blood. The long-term dietary PCB exposure assessments showed acceptable validity against six PCB congeners in serum (correlation coefficients 0.30 to 0.58). Cases of MI were ascertained via register-linkage through 2010. Relative risks (RR) and 95% confidence intervals (CI) were adjusted for known cardiovascular risk factors. : Results During 12 years of follow-up (433,243 person-years), we ascertained 3,005 incident cases of MI. The major dietary sources of PCB exposure was fish, dairy products and meat. Compared with the lowest quintile of dietary PCB exposure (median 113 ng/day), men in the highest quintile (median 436 ng/day) had multivariable-adjusted RR of 1.22 (95% CI, 1.05-1.41) for MI, without adjusting for the intake of marine omega-3 fish fatty acids. In a separate model, we observed no association between the intake of marine omega-3 fish fatty acids and MI (RR, 1.07; 95% CI, 0.93-1.24). In mutually-adjusted models, dietary PCB exposure was associated with RR 1.72 (95% CI 1.28-2.30), and the intake of marine omega-3 fish fatty acids with RR, 0.67 (95% CI, 0.50-0.90), comparing highest quintiles with lowest. Conclusions: Exposure to an integrated measure of total PCBs from food was associated with increased risk of MI in men. The results may provide important information regarding the risk-benefit analysis of fish consumption. To increase the net benefits of fish consumption, PCB contamination should be reduced to a minimum: Future studies are needed to clarify the concentrations of PCBs that may offset the beneficial effects of fish consumption.