Physical activity and renal cell cancer risk in a cohort of male smokers

Few studies have examined exercise in relation to risk of renal cell cancer. We examined the association between leisure-time and occupational physical activity and renal cell cancer in a cohort of 29,133 male smokers 50-69 years of age in the Alpha-Tocopherol, Beta-Carotene (ATBC) Cancer Prevention Study. Physical activity was assessed at baseline using a self-administered questionnaire that inquired about usual level of physical activity during leisure-time and at work during the past year. Cox proportional hazards modeling was used to adjust simultaneously for known or suspected risk factors for renal cell cancer. During 12 years (354,407 person-years) of follow-up, 210 incident cases of renal cell cancer were identified. In age-adjusted analysis, the RRs of renal cell cancer in increasing categories of leisure-time physical activity (light, moderate and heavy) were 1.0, 0.89 (95% CI = 0.67-1.17) and 0.38 (95% CI = 0.15-0.94), respectively (p-value for trend = 0.06). After adjustment for body mass index, energy intake, smoking, hypertension, education and fruit and vegetable intake, the multivariate RRs of renal cell cancer in increasing categories of leisure-time physical activity (light, moderate and heavy), were 1.0, 0.89 (95% CI = 0.66-1.19), and 0.46 (95% CI = 0.18-1.13) (p-value for trend = 0.12). Occupational physical activity was unrelated to renal cell cancer risk. These data suggest that recreational physical activity may play a role in the prevention of renal cell cancer in men.