Obesity, Diabetes Mellitus, Hypertension and other Risk Factors for Renal Cell Carcinoma in Japan: A Mini-Review

Background: The incidence of kidney cancer is high in Western Europe, Northern Europe and North America, while it is low in Asia. Although the incidence of kidney cancer in Japan is lower than the rates in the other industrialized countries, there is no doubt that it is increasing. In this paper, we would like to introduce the result of epidemiological studies, which evaluate the nongenetic risk factors for kidney cancer in the Japanese population. Methods: Relevant studies were identified in the PubMed database using the combination of “Japan”, “kidney cancer”, “renal cell cancer” and “risk”, and the ICHUSHI database (Japanese database) using a combination of “kidney cancer /renal cell cancer”, and “risk factor”. In addition, we selected one cohort study from the references of these reports. Results and Discussion: Several studies were identified in the database. In these studies, obesity, diabetes mellitus, hypertension, kidney diseases, chronic renal disease with dialysis, tobacco smoke, fondness for fatty food, milk, and black tea are associated with an increased risk of kidney cancer. On the other hand, an inverse association with the kidney cancer risk is found for an intake of starchy roots (i.e., taro, sweet potato and potato), physical activity and educational level. In Japan, however, drinking black tea and milk may be surrogates for a westernized dietary habit while eating starchy roots may be a surrogate for a traditional Japanese dietary habit. Additional studies are needed to confirm the risk factors for kidney cancer in the Japanese population.