Synopsis: This project will assess the mortality rates and causes among an existing, well-defined cohort of frequent and infrequent consumers of Great Lakes sportfish. This research will consider both the beneficial effects of a diet that includes freshwater and marine fish, as well as the adverse health effects of chronic exposure to persistent, bioaccumulative atmospheric contaminants of the Great Lakes basin on human health among an aging population. Substances that will be considered in this assessment include methylmercury, PCBs, PBDEs, and DDE. This work will evaluate age at death and causes of death among 2,542 frequent and 1,664 infrequent Great Lakes fish consumers. More than 3,000 members of this cohort, which includes Great Lakes charter captains, anglers, and non-anglers who were residing or fishing in the Great Lakes Basin in 1993-1994, are men over the age of 50 years.

Chemicals Studied: This study will assess the blood levels of several pollutants known to be present at high levels in many sport fish in the Great Lakes region. These include methylmercury, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dichlorodiphenyldichloroethylene (DDE, a persistent metabolite of DDT). Methylmercury is a form of mercury that can be produced in the environment from other mercury forms, accumulates in wildlife and human and has know adverse health impacts. PCBs are an industrial chemical that were used in numerous applications in the middle of the 20th century. Although banned from production in the U.S. and Canada, use of these chemicals remains in some “closed-system” applications. DDT was formerly used as a pesticide in North America and is still used in some parts of the world. PBDEs are currently used as a flame retardant in a wide range of commercial products, including consumer electronics and furniture, among many others.

Geographic Areas: The study includes a more than 4000 people from Wisconsin, Ohio, Michigan, Illinois and Indiana. When they began to participate in this study in 1993, these individuals were either licensed to conduct Charter Fishing operations, were frequent anglers or were infrequent consumers of Great Lakes fish.

Project Duration: The project will begin in the Spring of 2006 and will extend through the Spring or Summer of 2008. The project builds upon ongoing work that began more than ten years earlier.

Methods Used: Prior to the initiation of this study, cohorts have been established of frequent and infrequent consumers of Great Lakes sport fish. Total body burdens of the chemicals in question were assessed for all study participants. This project will track the health outcomes of the study participants and assess these results for relationships to fish consumption level and chemical body burden. Among this aging cohort with an average age of more than 55 years, the National Death Index will be used to identify deaths and associated causes among each group. In particular, deaths from cancer, endocrine disorders, degenerative neurological diseases and cardiovascular disease will be flagged. Comparisons for total mortality and specific causes will be made among groups and to the general population and will be assessed for relationships to the previously established chemical contaminant body burdens. In addition, an assessment will be made to identity evidence of any health benefits from fish consumption, such as a reduction in cardiovascular related deaths.
Potential Results and Implications: Finding of an association to total death rate or death from a specific cause with fish consumption patterns or chemical body burdens would provide important information regarding the need to protect sport fish consumers from exposure to chemicals and associated health impacts. Association of fish consumption or chemical exposure with protective health effects would also be an important outcome. Such findings would help public agencies throughout the Great Lakes region establish appropriate safely levels for fish consumption and produce guidance for citizens to help protect public health.

Project Contact:
Linda Knobeloch, Ph.D.
Wisconsin Department of Health and Family Services
Phone: (608)266-0923
Email: knobelm@dhfs.state.wi.us