Leisure-time physical activity and incident metabolic syndrome: a systematic review and dose-response meta-analysis of cohort studies

Background. Leisure-time physical activity (LTPA) has been suggested to reduce risk of metabolic syndrome (MetS). However, a quantitative comprehensive assessment of the dose response association between LTPA and incident MetS has not been reported. We performed a meta-analysis of studies assessing the risk of MetS with LTPA. Method. MEDLINE via PubMed and EMBase databases were searched for relevant articles published up to March 13, 2017. Random-effects models were used to estimate the summary relative risk (RR) of MetS with LTPA. Restricted cubic splines were used to model the dose response association. Results. We identified 16 articles (18 studies including 76,699 participants and 13,871 cases of MetS). We found a negative linear association between LTPA and incident MetS, with a reduction of 8% in MetS risk per 10 metabolic equivalent of task (MET) h/week increment. According to the restricted cubic splines model, risk of MetS was reduced 10% with LTPA performed according to the basic guideline-recommended level of 150 min of moderate PA (MPA) per week (10 MET h/week) versus inactivity (RR = 0.90, 95% CI 0.86-0.94). It was reduced 20% and 53% with LTPA at twice (20 MET h/week) and seven times (70 MET h/week) the basic recommended level (RR = 0.80, 95% CI 0.74-0.88 and 0.47, 95% CI 0.34-0.64, respectively). Conclusion. Our findings provide quantitative data suggesting that any amount of LTPA is better than none and that LTPA substantially exceeding the current LTPA guidelines is associated with an additional reduction in MetS risk. (C) 2017 Published by Elsevier Inc.