title: Mode of delivery and childhood fractional exhaled nitric oxide, interrupter resistance and asthma: the Generation R study.
abstract: BACKGROUND
  Previous studies suggest that caesarean section may influence the risk of childhood asthma. We examined the associations of different modes of delivery with childhood wheezing patterns, asthma, fractional exhaled nitric oxide (FeNO) and airway interrupter resistance (Rint) up to school age.
  
  
  METHODS
  This study among 6,128 children was embedded in a population-based prospective cohort study. Information on mode of delivery was obtained from midwives and hospital registries. Wheezing patterns from birth onwards and ever physician-diagnosed asthma at age 6 yr were assessed by questionnaires. FeNO and Rint were measured at age 6 yr. We used multivariate polynomial, logistic and linear regression models.
  
  
  RESULTS
  Compared with vaginal delivery, caesarean section was associated with increased risks of early and persistent wheezing up to school age [odds ratios (95% confidence interval): 1.36 (1.06, 1.75) and 1.73 (1.24, 2.40), respectively]. The effect sizes of elective and emergency caesarean section with wheezing outcomes were similar. Only elective caesarean section was associated with a higher FeNO level [sympercent (95% CI): 12.7 (0.6, 24.8)]. We did not observe associations of mode of delivery with asthma or Rint. Also, vacuum- or forceps-assisted vaginal delivery was not associated with any asthma or related outcome.
  
  
  CONCLUSIONS
  Both elective and emergency caesarean sections are associated with increased risks of early and persistent wheezing up to school age. This might be explained by increased airway inflammation reflected by higher FeNO levels.
authors.affiliation: The Generation R Study Group, Erasmus Medical Center, Rotterdam, The Netherlands.|Division of Respiratory Medicine, Department of Paediatrics, Erasmus Medical Center, Rotterdam, The Netherlands.|Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Annemaria C
authors.initials: AC
authors.lastname: van Berkel
authors.affiliation: The Generation R Study Group, Erasmus Medical Center, Rotterdam, The Netherlands.|Division of Respiratory Medicine, Department of Paediatrics, Erasmus Medical Center, Rotterdam, The Netherlands.|Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Herman T
authors.initials: HT
authors.lastname: den Dekker
authors.affiliation: The Generation R Study Group, Erasmus Medical Center, Rotterdam, The Netherlands.|Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.|Department of Paediatrics, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Vincent W V
authors.initials: VW
authors.lastname: Jaddoe
authors.affiliation: Division of Neonatology, Department of Paediatrics, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Irwin K
authors.initials: IK
authors.lastname: Reiss
authors.affiliation: The Generation R Study Group, Erasmus Medical Center, Rotterdam, The Netherlands.|Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Romy
authors.initials: R
authors.lastname: Gaillard
authors.affiliation: Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.affiliation: Division of Respiratory Medicine, Department of Paediatrics, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Johan C
authors.initials: JC
authors.lastname: de Jongste
authors.affiliation: Division of Respiratory Medicine, Department of Paediatrics, Erasmus Medical Center, Rotterdam, The Netherlands.|Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.|Division of Neonatology, Department of Paediatrics, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Duijts
mesh_terms: D000328:Adult; D000403:Airway Resistance / Q000502:physiology*; D001249:Asthma / Q000453:epidemiology* / Q000503:physiopathology; D002585:Cesarean Section / Q000706:statistics & numerical data; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D011247:Pregnancy; D011446:Prospective Studies; D018570:Risk Assessment; D011795:Surveys and Questionnaires
chemical_list: D009569:Nitric Oxide
keywords: asthma; cohort study; fractional exhaled nitric oxide; interrupter resistance; mode of delivery; wheezing