[Relationship between duration of low to moderate intensity physical activity and the prevalence of metabolic syndrome].

Objective: To analyze the relationship between low to moderate physical activity and the prevalence of metabolic syndrome (MS).

Methods: A multi-stage stratified cluster sampling was conducted in 31 provinces, autonomous regions, and municipalities in the interior of China according to the program of the National Nutrition and Health Survey in 2002. Questionnaire survey, interview, physical examination, measurement of biochemical indices and dietary investigation were done. In total, the physical activity of 26 477 persons aged 18 or above were investigated. The duration of low to moderate physical activity was divided into five grades: 0-min/week, 90-min/week, 151-min/week, 301-min/week, over 420 min/week, and the MS prevalence were investigated respectively. The relationship between MS and age (including four age groups 18-, 35-, 45-, 60 or above) or the duration of physical time were investigated.

Results: The MS prevalence among persons aged 18 or above was 9.4% (2490/26 477). And the prevalence was 10.3% (1191/11 516) in man and 8.7%(1299/14 961) in women, respectively (χ(2) = 21.035, P = 0.000). The MS prevalence was 2.1% (127/6070) in 18-years old group and 15.0% (1012/6734) in over 60 years old group. The MS prevalence increased with increasing age (χ(2) = 776.768, P = 0.000). 81.2% (21 499/26 477) of subjects engaged in low to moderate intensity physical activity. The percentage of spending time on physical activity over 420 min/week was dominant and as high as 43.7% (11 561/26 477). The MS prevalence was 13.8% (166/1203) for 0-min grade, 13.2% (64/485) for 90-min grade, 11.8% (153/1298) for 151-min grade, 10.1% (124/1225) for 301-min grade and 12.5% (512/4090) for over 420 min grade (χ(2) = 9.58, P = 0.047). Logistic regression analysis results showed, the MS risk of subjects spending 301-min per week on low to moderate intensity physical activity was significantly low than the MS prevalence among subjects of 90-min grade, OR = 0.844 (95%CI: 0.675 - 0.968), and no statistical difference was found in people spending over 420 min per week OR = 0.936(95%CI: 0.769 - 1.136).

Conclusion: Most of people aged 18 or above engaged in low to moderate intensity physical activity. MS prevalence may be decreased by low to moderate intensity physical activity for 301-min per week, but the decrease was not significant while the duration of time was longer than 420 min per week.