Walking and primary prevention: a meta-analysis of prospective cohort studies

Objective: To quantify the association between walking and the risk of cardiovascular disease (CVD) and all-cause mortality in healthy men and women. Data sources: Medline, Cochrane Database of Systematic Reviews, and Web of Science databases were searched to May 2007. Study selection: Prospective epidemiological studies of walking and CVD and all-cause mortality. Results: 18 prospective studies were included in the overall analysis, which incorporated 459 833 participants free from CVD at baseline with 19 249 cases at follow-up. From the meta-analysis the pooled hazard ratio of CVD in the highest walking category compared with the lowest was 0.69, (95% CI 0.61 to 0.77, p, 0.001), and 0.68 (0.59 to 0.78, p, 0.001) for all-cause mortality. These effects were robust among men and women, although there was evidence of publication biases for the associations with CVD risk. Walking pace was a stronger independent predictor of overall risk compared with walking volume (48% versus 26% risk reductions, respectively). There was also evidence of a dose response relationship across the highest, intermediate, and lowest walking categories in relation to the outcome measures. Conclusions: The results suggest walking is inversely associated with clinical disease endpoints and largely support the current guidelines for physical activity. The mechanisms that mediate this relationship remain largely unknown and should be the focus of future research.