Incidence and Mortality of Testis and Prostate Cancers in Relation to World Dietary Practices - Dairies are Causatively Related to these Malignancies

The incidence and mortality rates of testis and prostate cancers in 42 countries were correlated with the dietary practices in these countries using the cancer rates (1988-92) provided by the International Agency for Research on Cancer (IARC) and the food supply data (1961-90) provided by the Food and Agriculture Organization (FAO). Among the food items we examined, cheese was most closely correlated with the incidence of testis cancer at ages 20-39, followed by animal fats and milk. The correlation coefficient (r) was highest (r = 0.804) when calculated for cheese consumed during the period 1961-65 (maternal or prepubertal consumption). Stepwise-multiple-regression analysis revealed that milk + cheese (1961-65) made a significant contribution to the incidence of testis cancer (standardized regression coefficient [R] = 0.654). Concerning prostate cancer, milk (1961-90) was most closely correlated (r = 0.711) with its incidence, followed by meat and coffee. Stepwise-multiple-regression analysis identified milk + cheese as a factor contributing to the incidence of prostate cancer (R = 0.525). The food that was most closely correlated with the mortality rate of prostate cancer was milk (r = 0.766), followed by coffee, cheese and animal fats. Stepwise-multiple-regression analysis revealed that milk + cheese was a factor contributing most to the mortality of prostate cancer (R = 0.580). The results of our study suggest an important role of milk and dairy products in the development and growth of testis and prostate cancers. The close correlation between cheese and testis cancer and between milk and prostate cancer suggests that further mechanistic studies should be undertaken concerning the development of male genital organ cancers. Introduction Japanese lifestyle underwent drastic changes after the end of the Pacific War (1945). Most conspicuous was the change in dietary practices. The intake of milk and dairy products, meat