title: Mode of Delivery and Asthma at School Age in 9 European Birth Cohorts.
abstract: Evidence on the association between mode of delivery and asthma at school age is inconclusive. We assessed the associations between specific modes of delivery and asthma in children from 9 European birth cohorts that enrolled participants between 1996 and 2006. Cohort-specific crude and adjusted risk ratios for asthma at ages 5-9 years were calculated using Poisson regression models and pooled. A sensitivity analysis was carried out in children born at term to reduce confounding due to perinatal factors. The study included 67,613 participants. Cohort-specific rates of cesarean delivery varied from 9.4% to 37.5%. Cesarean delivery, as opposed to vaginal delivery, was associated with an increased risk of asthma (adjusted risk ratio (aRR) = 1.22, 95% confidence interval (CI): 1.02, 1.46). Compared with spontaneous vaginal delivery, the adjusted risk ratio was 1.33 (95% CI: 1.02, 1.75) for elective cesarean delivery, 1.07 (95% CI: 0.94, 1.22) for emergency cesarean delivery, and 0.97 (95% CI: 0.84, 1.12) for operative vaginal delivery. In children born at term, the associations were strengthened only for elective cesarean delivery (aRR = 1.49, 95% CI: 1.13, 1.97). The large sample size allowed analysis of the associations between specific modes of delivery and asthma at school age. The increased risk of asthma associated with elective cesarean delivery, especially among children born at term, is relevant in counteracting the increasing use of this procedure, which is often performed without a clear medical indication.
authors.forename: Franca
authors.initials: F
authors.lastname: Rusconi
authors.forename: Daniela
authors.initials: D
authors.lastname: Zugna
authors.forename: Isabella
authors.initials: I
authors.lastname: Annesi-Maesano
authors.forename: Nour
authors.initials: N
authors.lastname: Baïz
authors.forename: Henrique
authors.initials: H
authors.lastname: Barros
authors.forename: Sofia
authors.initials: S
authors.lastname: Correia
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Duijts
authors.forename: Francesco
authors.initials: F
authors.lastname: Forastiere
authors.forename: Hazel
authors.initials: H
authors.lastname: Inskip
authors.forename: Cecily C
authors.initials: CC
authors.lastname: Kelleher
authors.forename: Pernille S
authors.initials: PS
authors.lastname: Larsen
authors.forename: Monique
authors.initials: M
authors.lastname: Mommers
authors.forename: Anne-Marie Nybo
authors.initials: AN
authors.lastname: Andersen
authors.forename: John
authors.initials: J
authors.lastname: Penders
authors.forename: Katharine
authors.initials: K
authors.lastname: Pike
authors.forename: Daniela
authors.initials: D
authors.lastname: Porta
authors.forename: Agnes
authors.initials: A
authors.lastname: Sonnenschein-van der Voort
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.forename: Maties
authors.initials: M
authors.lastname: Torrent
authors.forename: Karien
authors.initials: K
authors.lastname: Viljoen
authors.forename: Martine
authors.initials: M
authors.lastname: Vrijheid
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Richiardi
authors.forename: Claudia
authors.initials: C
authors.lastname: Galassi
mesh_terms: D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D002585:Cesarean Section / Q000009:adverse effects* / Q000706:statistics & numerical data; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000379:methods* / Q000706:statistics & numerical data; D017558:Elective Surgical Procedures / Q000009:adverse effects / Q000706:statistics & numerical data; D005060:Europe / Q000453:epidemiology; D006801:Humans; D016012:Poisson Distribution; D015995:Prevalence; D011446:Prospective Studies; D047929:Term Birth
keywords: asthma; cesarean delivery; child; cohort studies