Prevalence of overweight and obesity in primary school students from Wenzhou city and the analyses of the risk factors

Objective To investigate the prevalence of overweight and obesity in primary school students from Wenzhou City in Zhejiang Province,and to explore their relative risk factors.Methods Multi-stage stratified cluster sampling method was used to select 9035 children from the primary schools in Wenzhou City for the anthropometric measurements.369 obesity cases and their paired controls of 389 children were chosen based on the large sample investigation.Diet and lifestyle factors were investigated in the nested case-control study for following logistic regression analyses.Results The overall prevalence of overweight and obesity was 11.2% and 6.4%,respectively.Male group had higher prevalence than female(P0.05).High frequency of vegetable intake,milk and dairy products intake,more physical activity were the benefit factors for preventing obesity(multi-variable logistic regression analysis,OR=0.770,0.821,0.697 and 0.567,P=0.033,0.037,0.017 and 0.008,respectively),whereas longer sedentary behavior was the risk factor of obesity(OR=1.583,P=0.003).Conclusions The prevalence of both overweight and obesity in students from the primary schools were high in Wenzhou city,and were highly related to the diet habit and physical activity.