Objective: African American children are at higher risk of obesity than White children and African American women are more likely to undergo caesarean-section (CS) delivery than White women. CS is associated with childhood obesity; however, little is known whether this relationship varies by race. We examined if the association of CS with obesity at age 2 years varied by race.
Design: Longitudinal birth cohort.
Setting: Birth cohort conducted in a health care system in metropolitan Detroit, Michigan with follow-up at age 2 years.
Participants: 639 birth cohort participants; 367 children (57.4%) were born to African American mothers and 230 (36.0%) children were born via CS.
Main outcome measures: Obesity defined as body mass index ≥95th percentile at age 2 years.
Results: Slightly more children of African American (n=37; 10.1%) than non-African American mothers (n=18; 6.6%) were obese (P=.12). There was evidence of effect modification between race and delivery mode with obesity at age 2 years (interaction P=.020). In children of African American mothers, CS compared to vaginal birth was associated with a significantly higher odds of obesity (aOR=2.35 (95% CI: 1.16, 4.77), P=.017). In contrast, delivery mode was not associated with obesity at age 2 years in children of non-African American mothers (aOR=.47 (95% CI: .13, 1.71), P=.25).
Conclusions: There is evidence for a race-specific effect of CS on obesity at age 2 years; potential underlying mechanisms may be racial differences in the developing gut microbiome or in epigenetic programming. Future research is needed to determine if this racial difference persists into later childhood.
Keywords: Birth Cohort; Childhood Obesity; Delivery Mode; Disparities; Race.