Abstract des Autors

Cancer is the leading cause of premature mortality in most developed countries. In Canada it accounted for the loss of 806,000 potential years of life in 1990. This report reviews evidence from human population studies concerning the relationship between one potentially modifiable lifestyle factor, physical activity, and cancers of the colon, rectum, breast, prostate, and lung. The biologically and immunologically plausible mechanisms for a relationship are also discussed. The strongest evidence of benefit relates to physical activity and colon cancer. Findings from at least 26 epidemiologic sötudies are remarkably consistent, showing that increased physical activity is modestly associated with a decreased incidence of colon cancer. Although there is biological evidence linking exercise and reduced risk of mammary tumor development, the human data are inconclusive due to imprecise measurement of physical activity, inadequate control of important confounding variables, and/or insufficient statistical power. Given the limited biologic and epidemiologic evidence suggesting a link between physical activity and cancers of the lung and prostate, no conclusions can be made. Verf.-Referat