[Association between cesarean birth and the risk of obesity in 6-17 year-olds].

To explore the association between cesarean section and obesity in child and adolescent. In this study, a total number of 42 758 primary and middle school students aged between 6 and 17 were selected, using the stratified cluster sampling method in 93 primary and middle schools in Hunan, Ningxia, Tianjin, Chongqing, Liaoning, Shanghai and Guangdong provinces and autonomous regions. Log-Binomial regression model was used to analyze the association between cesarean section and obesity in childhood or adolescent. Mean age of the subjects was (10.5±3.2) years. The overall rate of cesarean section among subjects attending primary or secondary schools was 42.3%, with 55.9% in boys and, 40.6% in girls respectively and with difference statistically significant (<0.001). The rate on obesity among those that received cesarean section (17.6%) was significantly higher than those who experienced vaginal delivery (10.2%) (<0.001). Results from the log-binomial regression model showed that cesarean section significantly increased the risk of obesity in child and adolescent (=1.72, 95%: 1.63-1.82; <0.001). After adjusting for factors as sex, residential areas (urban or rural), feeding patterns, frequencies of milk-feeding, eating high-energy foods, eating fried foods and the levels of parental education, family income, parental obesity, physical activity levels, gestational age and birth weight ., the differences were still statistically significant (=1.48, 95%: 1.39-1.57; <0.001). The rate of cesarean section among pregnant women in China appeared high which may significantly increase the risk of obesity in child or adolescent.