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

Objective: To explore the association between cesarean section and obesity in child and adolescent. Methods: 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. Results: 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 (P<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%) (P<0.001). Results from the log-binomial regression model showed that cesarean section significantly increased the risk of obesity in child and adolescent (OR=1.72, 95%CI: 1.63-1.82; P<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 etc., the differences were still statistically significant (OR=1.48, 95%CI: 1.39-1.57; P<0.001). Conclusion: The rate of cesarean section among pregnant women in China appeared high which may significantly increase the risk of obesity in child or adolescent.