Diabetes mellitus and kidney cancer risk: The results of Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC study)

Background: Diabetes mellitus (DM) is reported as being a risk factor associated with kidney cancer in Western countries. The incidence of both kidney cancer and DM is lower in Japan than the other developed countries, albeit on the rise. Methods: We evaluated the risk factors for kidney cancer mortality using the database of the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC) study. The analytic cohort included 46 462 males and 64 326 females aged 40-79 years old. The Cox proportional hazards model was used to determine age- and sex-adjusted relative risk and its 95% confidence intervals. Results: DM showed an increased, age- and sex-adjusted hazard ratio for kidney cancer mortality, but it failed to achieve statistical significance after controlling for other factors. Conclusion: The present study showed that DM increased the risk of kidney cancer death among the Japanese population. However, further studies may be needed to confirm the findings in the present study because DM failed to remain as a significant risk factor after controlling for other factors because of the small number of kidney cancer deaths in the present study.