Fish from the Great Lakes contain
polychlorinated biphenyls (
PCBs) which have been shown to disrupt endocrine function and mimic
thyroid hormones, but they also contain beneficial
omega-3 fatty acids that may offer protection against
endocrine cancers. The purpose of this study was to examine the effects of Lake Ontario fish consumption and the estimated consumption of
PCBs and
omega-3 fatty acids on the risk of
thyroid cancer in a group of sport fishermen. Anglers from the New York State Angler Cohort Study were followed for
cancer incidence from 1991-2008. Twenty-seven cases of incident
thyroid cancer and 108 controls were included in the analyses. Total estimated fish consumption, estimated
omega-3 fatty acid consumption, and estimated PCB consumption from Lake Ontario fish were examined for an association with the incidence of
thyroid cancer, while matching on sex, and controlling for age and smoking status. Results from logistic regression indicate no significant associations between fish consumption, short-term estimated
omega-3 fatty acids, or estimated PCB consumption from Great Lakes fish and the development of
thyroid cancer, but it was suggested that long-term
omega-3 fatty acid from Great Lakes fish may be protective of the development of
thyroid cancer. In conclusion, fish consumption, with the possible concomitant
PCBs, from the Great Lakes does not appear to increase the risk of
thyroid cancer in New York anglers. Further research is needed in order to separate the individual health effects of
PCBs from
omega-3 fatty acids contained within the fish.