Incidence and mortality of testicular and prostatic cancers in relation to world dietary practices

The incidence and mortality rates of testicular and prostatic 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 testicular 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 testicular cancer (standardized regression coefficient [R] = 0.654). Concerning prostatic 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 prostatic cancer (R = 0.525). The food that was most closely correlated with the mortality rate of prostatic 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 to mortality from prostatic cancer (R = 0.580). The results of our study suggest a role of milk and dairy products in the development and growth of testicular and prostatic cancers. The close correlation between cheese and testicular cancer and between milk and prostatic cancer suggests that further mechanistic studies should be undertaken concerning the development of male genital organ cancers. (C) 2002 Wiley-Liss, Inc.