Important aspects of the inverse relation between physical activity and colon cancer risk are still under discussion. In 2000–2003, 239 incident cases of colorectal cancer confirmed by histopathology and 239 hospital-based controls, matched by age and gender, were enrolled. In standardized interviews, data on occupational and recreational physical activity for ages 20, 30, 40, 50 and 60 years were collected from 98 colon cancer cases, 141 rectal cancer cases, and from 193 controls. Besides lifestyle and sociodemographic characteristics, a detailed food frequency questionnaire was assessed. In multivariate logistic regression for colon cancer, significant risk reductions for the highest quartile of total physical activity were found for almost all ages. For lifetime mean physical activity, the multivariate odds ratio for the highest quartile was 0.37 [95% confidence interval (CI) 0.17, 0.83]. For lifelong constantly high-exercisers compared with lifelong non-exercisers an odds ratio of 0.26 (95% CI 0.08, 0.84) was estimated. For rectal cancer, no consistent association with physical activity was found. No confounding effects were observed but the authors found effect modification with total energy intake. These data support an inverse association of colon cancer risk and physical activity which is most expressed if activity is kept up throughout life.
1Unit of Environmental Epidemiology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
2Chair of Epidemiology and Preventive Medicine, Jagiellonian University, Coll. Med. 7, Kopernika Street, Krakow, Poland
3First Chair of Surgery, Jagiellonian University, Coll. Med. 40, Kopernika Street, Krakow, Poland
Correspondence to: K Steindorf. Fax: (+49) 6221 422 229
Received 20 July 2004 Accepted 10 September 2004