Abstract

PIP: Prostate cancer is the most commonly diagnosed malignancy among US males. Its incidence, however, varies markedly from 2 per 100,000 per year in Shanghai, China, to 62 and 82, respectively, for US Whites and Blacks. Mortality due to prostate cancer is twice as high among US Blacks than among US Whites. A familial component is important in determining prostate cancer risk, but does not appear to explain the variation in rates between US Blacks and Whites. Dietary fat, the consumption of which varies on a national basis in parallel with prostate cancer rates, may be a major risk factor for the disease. A study by Whittemore et al. involved more than 1500 cases and controls including Whites, Blacks, Chinese-Americans, and Japanese-Americans in five cities in the US and Canada. On the basis of detailed dietary interviews, Whittemore shows that prostate cancer risk increases with higher intake of saturated fat. The effect holds true for both younger and older men. The risk was significantly elevated for Asian-Americans, and less pronounced for Blacks and Whites, yet nonetheless consistent with an overall excess. Risk was unrelated to the intake of other macronutrients, intake of vitamin A, intake of fruits and vegetables, body mass, or physical activity. Among Asian-Americans, long-term residents in the US were at greatest risk of prostate cancer independent of dietary fat intake. A study by John et al. has found vasectomy to not be related to the development of prostate cancer. Reasons why the finding of this study is opposite from the general body of evidence supporting an increased risk of prostate cancer following vasectomy are not apparent.