OBJECTIVETo explore the associations between behavioral risk factors and overweight and obesity among Chinese primary and middle school students in 2010.

METHODSA total of 149 912 primary and middle school students aged 9 - 18 were selected from "2010 National Physical Fitness and Health Surveillance" while underweight students excluded. Questionnaires and height, weight and other physical index were performed. Logistic regression was used to analyze the association between overweight, obesity and sleep time, diet, physical exercise intention and behavior as well as sedentary behavior.

RESULTSOf students surveyed, the proportion of short sleep time was higher in obese students than in normal weight students, the prevalence of short sleep time was 93.60% (118 394/126 491), 94.39% (15 053/15 947) and 95.09% (6782/7132) in normal weight, overweight and obese students, respectively (P < 0.05); the proportion of egg intake with no more than 3 times per week was lower in obese students than in normal weight students (56.49% (4025/7125) vs 65.25% (82 518/126 464)) (P < 0.05); the proportion of never drinking milk was lower in obese students than in normal weight students (7.08% (505/7134) vs 7.55% (9 545/126 503)) (P < 0.05); and when compared with those of normal (29.53%, 37 354/126 482), more overweight students reported that they had spent 2 or more hours on homework (30.17%, 4 809/15 941) (P < 0.05). The proportions of physical activity intentions were significantly lower in obesity group of male students than those of normal male group, and the proportion of liking physical education, being willing to participate in the extracurricular sports activities, and being willing to participate long running exercise was 67.7% (4828/7134), 71.2% (5083/7135) and 35.9% (2560/7135) in obese students compared with 68.6% (86 776/126 511), 72.6% (91 814/126 509) and 47.4% (59 914/126 512) in normal weigh students, respectively. In the 13 - 15 age group, the proportion of having been physically active for a total of at least 60 minutes per day was lower in obese group (19.87%, 376/1893) than in normal group (20.66%, 8 253/39 941) (P < 0.01). Logistic regression analysis showed that the students with short sleep time were more likely to get obesity than those without short sleep time (adjusted odds ratio (AOR): 1.11, 95%CI: 1.00 - 1.25). Egg intake with no more than 3 times per week was negatively associated with the probabilities of being at risk for obesity (AOR: 0.88, 95%CI: 0.83 - 0.92), while, never drinking milk was independently related to obesity (AOR: 1.14, 95%CI: 1.03 - 1.25). Disliking physical education (AOR: 1.23, 95%CI: 1.16 - 1.30), unwilling to participate long running exercise (AOR: 2.16, 95%CI: 2.05 - 2.28) and spending 2 or more hours on homework (AOR: 1.09, 95%CI: 1.02 - 1.15) were independently related to obesity. The patterns of influence factors in different groups were not alike.

CONCLUSIONOverweight and obesity prevalence was higher in China's primary and middle school students in 2010, and the bad dietary behavior, static life style were highly interconnected.