Abstract
BACKGROUND: It has not been clarified whether physical activity (PA) has more benefit in terms of health outcomes, including mortality risk, among those with metabolic syndrome (MS) compared to those without. Therefore, the aim of this study is to elucidate whether regular PA has interaction with MS on health outcomes. METHODS: Participants with no underlying cardiovascular diseases who underwent national health screening in 2009 were included. According to the metabolic equivalent (MET)-minutes/week, the amount of PA among the participants was grouped as follows: Group 1 (0 MET-minutes/week), Group 2 (1-499), Group 3 (500-999), Group 4 (1000-1499), and Group 5 (≥ 1500). Multivariable Cox proportional hazard models were applied to evaluate the impacts of the amount of PA on health outcomes among those with and without MS. Health outcomes included all-cause mortality and incident cardiovascular diseases (CVDs). RESULTS: Of 9,628,109 total participants, 335,970 deaths occurred during a median 8.3-year follow-up. After adjustment for age, sex, smoking status, alcohol consumption, and body mass index, the higher the PA amount was, the lower the risk of all-cause mortality in both those with MS [adjusted hazard ratio (aHR) compared with Group 1, 0.86 (95% CI 0.85, 0.87) in Group 2; 0.82 (95% CI 0.81, 0.83) in Group 3; 0.75 (95% CI 0.74, 0.77) in Group 4; and 0.78 (95% CI 0.76, 0.80) in Group 5; P for trend < 0.001] and those without MS [aHR compared with Group 1, 0.87 (95% CI 0.86, 0.88) in Group 2; 0.84 (95% CI 0.83, 0.85) in Group 3, 0.79 (95% CI 0.78, 0.80) in Group 4, and 0.82 (95% CI 0.81, 0.84) in Group 5; P for trend < 0.001]. The beneficial effects of the amount of PA on all-cause mortality were larger among those with MS than among those without MS in a multiplicative interaction (P for interaction < 0.001). The results were similar in the analysis of the relationship between the PA amount and incident CVD. CONCLUSIONS: More PA was associated with a lower risk of all-cause mortality, which was more prominent in those with MS than in those without MS. Physicians should emphasize more the importance of PA in patients with MS.