Cesarean section and body mass index in children: is there a causal effect?

Area of Science:

• Public Health
• Pediatrics
• Epidemiology

Background:

• Obesity is a global health concern.
• Cesarean section (CS) has been linked to higher childhood body mass index (BMI), but evidence is conflicting.
• Causal inference is needed to clarify the CS-BMI relationship.

Purpose of the Study:

• To investigate the causal effect of cesarean section on body mass index (BMI) in children aged 1-3 years.
• To address conflicting findings regarding the association between birth mode and childhood obesity.
• To utilize advanced statistical methods for robust causal inference.

Main Methods:

• Cohort study design using the BRISA Birth Cohort (n=2,181 children aged 1-3 years).
• Data collected on sociodemographics, maternal factors, birth mode, and anthropometry.
• Marginal structural models with counterfactuals and inverse probability weighting were employed to assess causality.

Main Results:

• No statistically significant causal effect of cesarean section on children's BMI was detected (coefficient = -0.004; 95% CI: -0.136; 0.127; p = 0.948).
• Cesarean section was not found to be a causal determinant of excess weight or higher BMI in the studied age group.
• The prevalence of cesarean birth was 50.6%, and 10.7% of children had excess weight.

Conclusions:

• Cesarean section does not appear to have a causal impact on body mass index (BMI) in children aged 1-3 years.
• The findings challenge previous associations suggesting a link between birth by cesarean and later obesity.
• Further research may explore other factors influencing childhood BMI development.