Lifestyle factors and XXXX risk (2): a systematic review and meta-analysis of associations with leisure-time physical activity.

@entity1 @entity694 @entity5 @entity14
OBJECTIVE: Increased physical activity may decrease the risk of @entity14 . 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 @entity694 , there were inverse associations with LT-PA for @entity1 (RR: 0.80; 95% CI: 0.67-0.96) and @entity1 (0.86; 0.76-0.98). LT-PA did not influence risk of @entity5 . The dose-response analysis was consistent with linear pattern reductions in risk of @entity694 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 @entity5 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 @entity14 incidences.
