Objective: To investigate the relationship between physical activity and metabolic syndrome (MS).
Methods: A multi-stage stratified cluster sampling was conducted in 132 sampling 218,920 residents, aged 44.3 +/- 15.3 (15 - 96), in the 31 provinces, autonomous regions, and municipalities of the mainland China according to the program of the National Nutrition and Health Survey. Questionnaire survey, interview, physical examination, measurement of biochemical indices, and dietary investigation were done. Information of physical activity and measurement of fasting glucose and/or glucose 2 hours after meal, blood pressure, triglycerides, high-density lipoprotein cholesterol were obtained in 50,494 participants. Metabolic syndrome was defined according to the Chinese Medical Association's definition. The intensity of physical activity was divided into 3 categories according to the Center for Disease Control and Prevention of US/American College of Sports Medicine criteria.
Results: 50,495 subjects, 23,932 males (47.4%) and 26,562 females (52.6%), were diagnosed as with MS. The MS incidence of those with high intensity of physical activity was lower by 60% in comparison with those with low intensity of physical activity (odds ratio 0.60, 95% CI: 0.362 - 0.443) adjusted for age, sex, smoking, and alcohol intake. The risk of MS in those with moderate intensity of physical activity of 151 - 300 minutes/week was slightly decreased compared to those with moderate intensity of physical activity of 90 - 150 minutes/week, (odds ratio 0.935, 95% CI: 0.685 - 1.277), however, the risk of MS in those with the moderate intensity of physical activity over 300 minutes/week increased slightly (OR = 1.269, 95% CI: 0.923 - 1.745). The risk of MS in those with low-level physical activity of 301 - 420 minutes/week was lower by 35% in comparison with those with the low-level physical activity of 90 - 150 minutes/week (95% CI: 0.451 - 0.933), however, the risk of MS in those with the low-level physical activity over 420 minutes/week was 0.871, not significantly different from that of the subjects with the low-level physical activity of other intensity (odd ratio = 0.871, 95% CI: 0.643 - 1.181). The risk of MS of those with the vigorous physical activity odds rations for having MS of vigorous activity over 150 minutes/week was 0.757, lower by 25% in comparison with those with the vigorous physical activity of 10 - 60 minutes/week (95% CI: 0.603 - 0.951), adjusted for sex, age, smoking, alcohol intake and BMI.
Conclusion: MS risk can be decreased by low level physical activity of 300 - 420 minutes/week, moderate physical activity of 90 - 300 minutes/week and vigorous physical activity of over 150 minutes/week.