Associations of leisure-time physical activity with cardiovascular mortality: A systematic review and meta-analysis of 44 prospective cohort studies.

Background Many cohort studies within the past few decades have shown the protective effect of leisure-time physical activity on cardiovascular mortality. To summarise the evidence from prospective cohort studies on the relationship between the amount of leisure-time physical activity and the risk of cardiovascular mortality, a dose-response meta-analysis was conducted in this study. Methods and results Electronic databases, including PubMed and Embase databases, Scopus and Cochrane Library, were systemically retrieved by two investigators from inception to 14 June 2018 for related studies. The maximum adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were extracted, and a dose-response analysis was conducted using the restricted cubic splines. Finally, a total of 44 studies comprising 1,584,181 participants was enrolled into this meta-analysis. The HRs of cardiovascular mortality for moderate and high leisure-time physical activity were 0.77 (95% CI 0.74-0.81) and 0.73 (95% CI 0.69-0.77), respectively. Among these 44 studies, 19 were eligible for the dose-response meta-analysis, which suggested a linear negative correlation of leisure-time physical activity with cardiovascular mortality, regardless of age, gender and the presence of underlying cardiovascular disease or not. Conclusions Leisure-time physical activity shows a linear negative correlation with the risk of cardiovascular mortality regardless of age, gender and the presence of cardiovascular disease or not. However, the cardiovascular benefits of leisure-time physical activity is decreased for those aged over 65 years or those with a history of cardiovascular disease. Moreover, leisure-time physical activity displays more cardiovascular benefits to people followed up for over 10 years than to those followed up for less than 10 years. Besides, high-intensity leisure-time physical activity has more obvious cardiovascular benefits than those of moderate-intensity leisure-time physical activity.