Caesarean delivery is associated with higher risk of overweight in the offspring: within-family analysis in the SUN cohort

Abstract

BackgroundMost studies assessing the association between caesarean delivery (CD) and childhood overweight/obesity have failed to account for important confounders, such as maternal prepregnancy body mass index (BMI) or the indication of the CD. Furthermore, within-family analyses have reported contradictory results. We aimed at evaluating the association between CD and offspring’s risk of overweight/obesity while adjusting for important confounders and accounting for correlations between siblings.MethodsWomen in the ‘Seguimiento Universidad de Navarra’ cohort provided structured information regarding their pregnancy history and their children’s health through online cross-sectional questionnaires. We calculated adjusted differences in BMI z-score and risk ratios (RR) for offspring’s overweight/obesity associated with CD, with hierarchical models to account for correlations between siblings. We also performed a within-family analysis in 341 siblings who were discordant in delivery mode, using conditional multivariable logistic regression.ResultsAmong the 2791 children analysed, those born by CD had higher average BMI z-scores (difference: 0.17; 95% CI 0.07 to 0.27) and higher risk of overweight/obesity (RR: 1.32, 95% CI 1.05 to 1.65) than children born vaginally. The association did not differ by maternal characteristics or offspring’s age strata, and the results were consistent in sensitivity analyses. Furthermore, within-family analysis showed that children born by CD had 2.67-fold higher risk of overweight/obesity (95% CI 1.10 to 5.12) than their peers born vaginally.ConclusionChildren born by CD have higher average BMI z-scores and higher risk of overweight/obesity than children born vaginally. The consistency of these findings across multiple approaches to address potential residual confounding likely suggests a true biological effect.

Birth by Caesarean Section and Offspring Overweight and Obesity in Adult Life: A Systematic Review and Meta-analysis

“…Table 1: Main characteristics of studies included in the systematic review and meta-analysis on birth by Cesarean Section (CS) and offspring overweight/obesity. In our selection, 9 studies [29,30,31,32,33,34,35,36,37] have prospective study design and two studies have retrospective study design [38,39]. Two studies reported subtype of CS (Elective CS and Non elective CS) [29,39], four studies investigated the association of CS with overweight and obesity [29,33,37,39], one the association of CS with overweight [35] and six the association of CS with obesity [30,31,32,34,36,38].…”

“…In our selection, 9 studies [29,30,31,32,33,34,35,36,37] have prospective study design and two studies have retrospective study design [38,39]. Two studies reported subtype of CS (Elective CS and Non elective CS) [29,39], four studies investigated the association of CS with overweight and obesity [29,33,37,39], one the association of CS with overweight [35] and six the association of CS with obesity [30,31,32,34,36,38]. Four studies were conducted in Europe (in particular, two in Denmark [35,39], one in Spain [37], one in Sweden [29]), 3 studies in USA [31,34,36], 2 studies in south America (Brazil) [30,32], one in Australia [33]and the remaining one in Africa (South Africa) [38].…”

“…Four studies were conducted in Europe (in particular, two in Denmark [35,39], one in Spain [37], one in Sweden [29]), 3 studies in USA [31,34,36], 2 studies in south America (Brazil) [30,32], one in Australia [33]and the remaining one in Africa (South Africa) [38]. Five studies reported RR (29,31,34,36,37), three reported OR (33,35,38) and three reported PR (30,32,39). Among the studies, five reported overall risk estimates in offspring [30,31,33,34,37], one study reported risk estimates for females' sex only [36] and two studies for males' sex only [29,39], while the three studies reported risk estimates for both sexes [32,35,38].…”

“…Five studies reported RR (29,31,34,36,37), three reported OR (33,35,38) and three reported PR (30,32,39). Among the studies, five reported overall risk estimates in offspring [30,31,33,34,37], one study reported risk estimates for females' sex only [36] and two studies for males' sex only [29,39], while the three studies reported risk estimates for both sexes [32,35,38]. Four studies investigated the risk of overweight in adults aged 18-20 years [29,35,37,39] and one study in adults aged 21 or more years [33].…”

“…Among the studies, five reported overall risk estimates in offspring [30,31,33,34,37], one study reported risk estimates for females' sex only [36] and two studies for males' sex only [29,39], while the three studies reported risk estimates for both sexes [32,35,38]. Four studies investigated the risk of overweight in adults aged 18-20 years [29,35,37,39] and one study in adults aged 21 or more years [33]. Obesity was the outcome of interest in four studies investigating adults aged 18-20 years [29,31,37,39] and five studies investigating adults aged 21 or more years [ 30,32,36,38,39].…”