Prelabor Cesarean Section and Risk of Childhood Type 1 Diabetes A Nationwide Register-based Cohort Study

Background: Unfavorable conditions associated with cesarean section may influence the risk of type 1 diabetes in offspring, but results from studies are conflicting. We aimed to evaluate the association between prelabor cesarean section and risk of childhood type 1 diabetes. Methods: A Danish nationwide cohort study followed all singletons born during 1982-2010. Four national registers provided information on mode of delivery, outcome, and confounders. The risk of childhood type 1 diabetes with onset before the age of 15 years was assessed by Cox regression. A total of 1,760,336 singletons contributed 20,436,684 person-years, during which 4,400 were diagnosed with childhood type 1 diabetes. Results: The hazard ratio (HR) for childhood type 1 diabetes was increased in children delivered by prelabor cesarean section compared with vaginal delivery when adjusted for year of birth, parity, sex, parental age, and education and paternal type 1 diabetes status at childbirth (HR = 1.2; 95% confidence interval [CI] = 1.0, 1.3), but not after additional adjustment for maternal type 1 diabetes status at childbirth (HR = 1.1; 95% CI = 0.95, 1.2). Delivery by intrapartum cesarean section was not associated with childhood type 1 diabetes. Paternal type 1 diabetes was a stronger risk factor for childhood type 1 (HR = 12; 95% CI = 10, 14) than maternal type 1 diabetes (HR = 6.5; 95% CI = 5.2, 8.0). Conclusions: Delivery by prelabor cesarean section was not associated with an increased risk of childhood type 1 diabetes in the offspring.