Cesarean section and risks of overweight and obesity in school-aged children: a population-based study

Background: Obesity puts a great health burden in the world. Previous studies suggest that caesarean section (CS) may increase the risk of obesity in children, but it is still uncertain whether this association is causal or due to residual confounding by medical indication. Aim: To assess the association between CS, CS without medical indications in particular and the risk of overweight and obesity in school-aged children. Design: Cross-sectional survey. Methods: The 2014 Shanghai Child Health, Education and Lifestyle Evaluation was a large population-based survey with cluster random probability sampling in 26 primary schools in Shanghai, China, in 2014. The mode of delivery was reported by parents. The height, weight and waist circumference of the children were measured. Logistic regression models with SURVEYLOGISTIC procedure were used to estimate the risk of childhood obesity. Pupils delivered vaginally were served as the reference group. Results: A total of 17 571 pupils completed this survey, and 13 724 of them who were singleton, born term and between 5 and 13 years old were included in our analysis. CS was associated with increased risks of overweight and obesity (BMI: adjusted OR = 1.28 [95% CI 1.13-1.45] and 1.44 [1.26-1.66], respectively; weight for height ratio [WHtR] >0.46: 1.33 [1.20-1.48]). Similar results were found in CS without medical indication (BMI: overweight = 1.24 [1.05-1.47], obesity = 1.43 [1.19-1.72]; WHtR > 0.46: 1.30 [1.13-1.50]). Conclusions: CS overall and CS without medical indications were associated with increased risks of overweight and obesity in primary school children.