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Weinvestigated several aspects of the role of physical activity in colon andrectal cancer etiology that remain unclear in the European ProspectiveInvestigation into Nutrition and Cancer. This cohort of 413,044 men and womenhad 1,094 cases of colon and 599 cases of rectal cancer diagnosed during anaverage of 6.4 years of follow-up. We analyzed baseline data on occupational,household, and recreational activity to examine associations by type ofactivity, tumor subsite, body mass index (BMI), and energy intake. Themultivariate hazard ratio for colon cancer was 0.78 [95% confidence interval(95% CI), 0.59-1.03] among the most active participants when compared with theinactive, with evidence of a dose-response effect (P(trend) = 0.04). Forright-sided colon tumors, the risk was 0.65 (95% CI, 0.43-1.00) in the highestquartile of activity with evidence of a linear trend (P(trend) = 0.004). Activeparticipants with a BMI under 25 had a risk of 0.63 (95% CI, 0.39-1.01) forcolon cancer compared with the inactive. Finally, an interaction between BMIand activity (P(interaction) = 0.03) was observed for right-sided coloncancers; among moderately active and active participants with a BMI under 25, a risk of 0.38 (95% CI,0.21-0.68) was found as compared with inactive participants with BMI >30. Nocomparable decreased risks were observed for rectal cancer for any type ofphysical activity for any subgroup analyses or interactions considered. We foundthat physical activity reduced colon cancer risk, specifically for right-sidedtumors and for lean participants, but not rectal cancer. Leggi l'articolo