Overweight and obesity in adults and risk of renal cell carcinoma in Canada

Objectives: To assess the role of overweight and obesity in renal cell carcinoma (RCC) risk in Canada. Methods: Mailed questionnaires were used to obtain data on 1279 (691 male and 588 female) newly diagnosed, histologically confirmed RCC cases and 5370 population controls, between 1994 and 1997, in eight Canadian provinces. Data were collected on socio-economic status, height, weight, smoking habits, alcohol use, diet, and residential and occupational histories. Weight was expressed as body mass index (BMI). Odds ratios (ORs) and 95% confidence intervals (CIs) were derived using unconditional logistic regression. Results: The study found an increased risk of RCC associated with overweight and obesity among both male and female adults; the test for trend was statistically significant (p < 0.0001 for both sexes). Compared with normal BMI, the adjusted ORs for obese class III (BMI >= 40.00) were 3.7 (95% CI = 1.5-9.4) and 3.8 (95% CI = 2.3-6.4) among males and females, respectively. Conclusions: These findings indicate that overweight and obesity play an important role in the etiology of renal cell among both males and females.