Lifestyle factors and colorectal cancer risk (2): a systematic review and meta-analysis of associations with leisure-time physical activity
Article first published online: 17 JAN 2009
© 2009 The Authors. Journal Compilation © 2009 The Association of Coloproctology of Great Britain and Ireland
Volume 11, Issue 7, pages 689–701, September 2009
How to Cite
Harriss, D. J., Atkinson, G., Batterham, A., George, K., Tim Cable, N., Reilly, T., Haboubi, N., Renehan, A. G. and The Colorectal Cancer, Lifestyle, Exercise And Research Group (2009), Lifestyle factors and colorectal cancer risk (2): a systematic review and meta-analysis of associations with leisure-time physical activity. Colorectal Disease, 11: 689–701. doi: 10.1111/j.1463-1318.2009.01767.x
- Issue published online: 7 AUG 2009
- Article first published online: 17 JAN 2009
- Received 7 August 2008; accepted 26 August 2008
- Colorectal cancer;
- leisure-time physical activity;
- systematic review;
Objective Increased physical activity may decrease the risk of colorectal cancer. As a prerequisite to the determination of lifestyle attributable risks, we performed a systematic review and meta-analysis of prospective observational studies to quantify gender-specific risk associated with increased leisure-time physical activity (LT-PA).
Method We searched MEDLINE and EMBASE (to December 2007), and other sources, selecting reports based on strict inclusion criteria. We used random-effects meta-analyses to estimate summary risk ratios (RR) and 95% confidence intervals (95% CI) for uppermost vs lowermost categories of physical activity. To investigate dose–response, we explored risks ratios as a function of cumulative percentiles of physical activity distribution.
Results Fifteen datasets from 14 articles, including 7873 incident cases, were identified. For colon cancer, there were inverse associations with LT-PA for men (RR: 0.80; 95% CI: 0.67–0.96) and women (0.86; 0.76–0.98). LT-PA did not influence risk of rectal cancer. The dose–response analysis was consistent with linear pattern reductions in risk of colon cancer in both genders. There was evidence of moderate between-study heterogeneity but summary estimates were broadly consistent across potential confounding factors.
Conclusion Increased LT-PA is associated with a modest reduction in colon but not rectal cancer risk; a risk reduction, which previously may have been overstated. LT-PA only interventions in public health cancer prevention strategies are unlikely to impact substantially on colorectal cancer incidences.