Diet and lung cancer risk from a 14-year population-based prospective study in Japan: with special reference to fish consumption.

N-3 polyunsaturated fatty acids in fish oil exhibit a variety of health benefits, and there is evidence that they can inhibit the development of human lung mucoepidermoid and other carcinomas. To examine the hypothesis that fish consumption reduces the risk of lung cancer, we conducted a population-based prospective study, following 5,885 residents for 14 yr. Person-years were used to calculate the relative risk (RR) by the Cox proportional hazards model, with adjustment for potential confounding factors. A total of 51 incident lung cancer cases were observed, and we found linearly decreasing RRs for lung cancer with increased frequency of consumption of fish and shellfish (RRs = 1.00, 0.99, and 0.32, P for trend = 0.003) but not with intake of dried/salted fish. Decreased RRs were apparent with both broiling and boiling cooking methods, but reduction with raw and deep-fried fish consumption was not statistically significant. We conclude that frequent fresh fish consumption, irrespective of the cooking method, may reduce the risk of lung cancer.