Nutrition and renal cell cancer.

Epidemiologic evidence on the relation between nutrition and renal cell cancer is reviewed. Kidney cancer, comprising 1.7 percent of all malignant diseases diagnosed worldwide, shows about a 20-fold international variation in the incidence in men and 10-fold in women. This substantial variation indicates an important causal role of environmental factors. Renal cell (parenchymal) cancer (RCC) accounts for about 80 percent of all kidney cancers. While the etiology of RCC is incompletely understood, analytic epidemiologic studies provide consistent support for a positive association of obesity with risk of RCC; the dose-response observed supports a causal relationship. Only a few prospective studies, all of them limited in size, have been published, while ecologic and case-control studies suggest that diet may be important in the etiology of RCC. However, contradictory results and methodologic limitations in some case-control studies prevent definite conclusions concerning diet and RCC. A positive association of protein and fat intake, as well as their main food sources (meat, milk, fats), with risk of RCC-as suggested by ecologic studies-has no clear support in analytic epidemiologic studies. A protective effect of vegetables and fruits has been observed in most case-control studies, while the majority do not show an association between alcohol, coffee, and risk of RCC. Recent reports indicated an increased risk of RCC associated with consumption of fried/sautéed meat and low intakes of magnesium or vitamin E. An apparent positive association with total energy intake, perhaps due to bias, needs further investigation.