Objectives: Previous studies have observed notable unexplained geographic differences in incidence of kidney cancer in Europe. Lithuania is among the countries with the highest incidence and mortality. Our objective was to investigate the effect of different lifestyle, anthropometric and biological factors on the risk of kidney cancer in Lithuanian men.
Methods: This population-based cohort study included 6,849 men initially free from cancer. During the follow-up (1978-2008), 79 incident cases of kidney cancer were identified. Cox proportional hazards regression models were used to estimate hazard ratios (HR) and corresponding 95% confidence intervals (95% CI).
Results: Risk of kidney cancer was significantly associated with increasing body mass index (BMI), the adjusted HR for ≥ 35 vs. < 25 kg/m2 was 3.00, 95% CI 1.10-8.19 and the HR per 1 unit increment of BMI was 1.07, 95% CI 1.01-1.14. In overweight men (BMI ≥ 25 kg/m2), the HRs for kidney cancer per 10 mmHg increment of systolic or diastolic blood pressure were 1.10, 95% CI 0.96-1.25 and 1.26, 95% CI 1.01-1.56, respectively. We found no significant association between smoking, alcohol consumption or total serum cholesterol level and kidney cancer risk.
Conclusions: This study supports a link between increased BMI and the development of kidney cancer among men in Lithuania. Hypertension appears to be associated with risk of kidney cancer in overweight men, although the assessment was limited by the lack of statistical power.
Keywords: body mass index; cohort study; hypertension; kidney cancer; risk factors.