Objective: To evaluate prospectively the association between intakes of fish, marine fatty acids, and bladder cancer risk in two ongoing cohorts, the Health Professionals Follow-up Study and the Nurses' Health Study.
Methods: During 16 and 18 years of follow-up, 501 and 235 incident cases of bladder cancer were diagnosed among men and women, respectively. Cox proportional hazard models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) between fish intake and bladder cancer risk adjusting for age, total caloric intake, pack-years of cigarette smoking, and current smoking.
Results: We observed no significant overall association between total fish intake and bladder cancer risk, even when we compared >/=1 servings of fish per day to fish intake </=1-3 servings per month. Among men, a statistically significant lower risk of bladder cancer was observed among men consuming fish or high marine fatty acid, after excluding the first 4 years of follow-up (MV RR = 0.60; 95% CI, 0.38-0.94, for >/=1 total fish servings per day compared to </=1-3 servings per month).
Conclusions: Overall, these findings suggest that fish intake is not likely to be appreciably associated with the risk of bladder cancer.