Mortality among frequent consumers of Great Lakes sport fish

Commercial and sport-caught fish provide a healthy source of dietary protein, omega-3 fatty acids, and other micronutrients. Regular fish consumption has been associated with decreased risk of heart disease and health professionals encourage adults to include fish in their weekly diets. However, fish harvested from contaminated waters can contain higher levels of persistent, bioaccumulative chemicals such as methylmercury, PCBs, dieldrin, and DDT. To assess the beneficial effects of fish intake and the adverse effects of contaminant exposure, underlying and contributing causes of death were obtained from the National Death Index for 342 deceased members of a cohort of 2538 Great Lakes charterboat captains, 180 Wisconsin anglers, and 1141 referents who were established in 1993-1995. Multivariate analysis of death rates confirmed a dose-related protective effect of fish intake against all-cause and cardiovascular disease mortality, including coronary heart disease, among the referent group. This effect was not observed among consumers of Great Lakes sport fish, however. Cancer mortality was not associated with fish intake in either exposure group. While the number of deaths among this cohort is currently too small to support rigorous statistical analysis, these preliminary findings are consistent with other studies that have shown a protective effect of commercial fish on human health and longevity and raise concerns regarding the effect of persistent environmental contaminants that continue to be detected in fish from the Great Lakes Basin. It is hoped that continued monitoring of this cohort will improve our understanding of the complex interactions that exist between nutrients and contaminants found in fish harvested from the Great Lakes.