Background: An increased risk of renal cell cancer (RCC) has been reported in subjects with hypertension. Whether this association may vary according to sex, smoking, obesity, or RCC clinical presentation is unclear. Results on the link between diabetes mellitus and RCC are inconclusive. Patients and methods: We conducted an Italian multicenter case-control study, including 767 (494 men, 273 women) incident cases of RCC, under 80 years of age, and 1534 hospital controls, frequency-matched to cases. Multiple logistic regression models, conditioned to center, sex, and age, and adjusted for period of interview, education, smoking, and body mass were used to estimate odds ratios (OR). Results: Compared with subjects never treated, patients with a history of treated hypertension [OR = 1.7, 95% confidence interval (CI) 1.4-2.1] reported an excess risk of RCC. This pattern was confirmed in different strata of sex, education, smoking habits, body mass, tumor histological type, stage, or grade. The attributable risk of RCC for treated hypertension in this population was 16%. A slight, nonsignificant increased risk was found for history of diabetes mellitus (OR = 1.3, 95% CI 0.9-1.7). Conclusion: A possible causal role of hypertension in renal cell carcinogenesis is supported by the consistency of the direct association.
