Type 2 Diabetes and the Risk of Renal Cell Cancer in Women

OBJECTIVE Type 2 diabetes is associated with increased risks of several types of cancer; however, its relationship to renal cell cancer remains unclear. RESEARCH DESIGN AND METHODS A total of 118,177 women aged 30 to 55 years at baseline (1976) were followed up through 2008 in the Nurses' Health Study. Self-reports of physician-diagnosed diabetes were collected at baseline and updated biennially. Hazard ratios (HRs) were calculated using Cox proportional hazards models with adjustment for age, BMI, hypertension, smoking, and parity. RESULTS During 32 years of follow-up (3,531,170 person-years), 16,819 cases of type 2 diabetes and 330 cases of pathology-confirmed incident renal cell cancer were documented. After multivariate adjustment, type 2 diabetes was significantly associated with an increased risk of renal cell cancer (HR 1.60 [95% CI 1.19-2.17]). These associations were consistent across different strata of BMI, smoking, and hypertension (Pinteraction≥0.32). The risk of renal cell cancer increased with an increasing number of comorbidities, including obesity, hypertension, and type 2 diabetes (Ptrend<0.001). When compared with women without any comorbidity, women who had all three conditions had a HR of 4.13 (2.76-6.18) for renal cell cancer. CONCLUSIONS Type 2 diabetes is independently associated with an increased risk of renal cell cancer in women. In addition, comorbidity of obesity, hypertension, and type 2 diabetes substantially elevates the risk of renal cell cancer.