They collected information about the level of physical activity and the incidence of colon cancer in the 31,783 women from the Breast Cancer Detection Demonstration Project Follow-up Study. They found 243 cases of colon cancer between 1989 to 1998. However, they were unable to find any link between exercise and colon cancer, "The results of this large prospective cohort study among women do not support the hypothesis that physical activity is related to a lower incidence of colon cancer," the authors said. They acknowledge that there might have been several imperfections in the analysis, but this could only confer a marginal benefit if any, "Our results do not support the hypothesis that physical activity confers significant protection against the overall development of colon cancer in women.
Our findings point towards the need for conducting further research, particularly among women, that uses well-formulated, accurate measures of physical activity and distinguishes between different types of physical activity (i.e. recreational, occupational, and household activity) in relation to colon cancer risk," they conclude.
http://www.interscience.wiley.com/journal/ijc Article: "Physical Activity and the Risk of Colon Cancer Among Women: A Prospective Cohort Study (United States)," by Brook A. Calton, James V. Lacey Jr., Arthur Schatzkin, Catherine Schairer, Lisa H. Colbert, Demetrius Albanes, and Michael F. Leitzmann, International Journal of Cancer; Published Online: February 17, 2006 (DOI: 10.1002/ijc.21840). Contact: David Greenberg email@example.com 201-748-6484 John Wiley & Sons, Inc.