Thorax 64:107-113 doi:10.1136/thx.2008.100875
  • Asthma

Asthma at 8 years of age in children born by caesarean section

  1. C Roduit1,
  2. S Scholtens2,
  3. J C de Jongste3,
  4. A H Wijga1,
  5. J Gerritsen4,
  6. D S Postma4,
  7. B Brunekreef2,5,
  8. M O Hoekstra6,
  9. R Aalberse7,8,
  10. H A Smit1,5
  1. 1
    Centre for Prevention and Health Services Research, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
  2. 2
    Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
  3. 3
    Department of Pediatrics, Division of Respiratory Medicine, Erasmus MC – Sophia, Rotterdam, The Netherlands
  4. 4
    Beatrix Children’s Hospital, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
  5. 5
    Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
  6. 6
    Centre for Paediatric Allergology, Wilhelmina Children’s Hospital, Utrecht, The Netherlands
  7. 7
    Sanquin Research, Amsterdam, The Netherlands
  8. 8
    Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
  1. Dr H A Smit, National Institute for Public Health and the Environment (RIVM), Centre for Prevention and Health Services Research (pb 101), P O Box 1, 3720 BA Bilthoven, The Netherlands; jet.smit{at}
  • Received 25 April 2008
  • Accepted 7 September 2008
  • Published Online First 3 December 2008


Background: Caesarean section might be a risk factor for asthma because of delayed microbial colonisation, but the association remains controversial. A study was undertaken to investigate prospectively whether children born by caesarean section are more at risk of having asthma in childhood and sensitisation at the age of 8 years, taking into account the allergic status of the parents.

Methods: 2917 children who participated in a birth cohort study were followed for 8 years. The definition of asthma included wheeze, dyspnoea and prescription of inhaled steroids. In a subgroup (n = 1454), serum IgE antibodies for inhalant and food allergens were measured at 8 years.

Results: In the total study population, 12.4% (n = 362) of the children had asthma at the age of 8 years. Caesarean section, with a total prevalence of 8.5%, was associated with an increased risk of asthma (OR 1.79; 95% CI 1.27 to 2.51). This association was stronger among predisposed children (with two allergic parents: OR 2.91; 95% CI 1.20 to 7.05; with only one: OR 1.86; 95% CI 1.12 to 3.09) than in children with non-allergic parents (OR 1.36; 95% CI 0.77 to 2.42). The association between caesarean section and sensitisation at the age of 8 years was significant only in children of non-allergic parents (OR 2.14; 95% CI 1.16 to 3.98).

Conclusions: Children born by caesarean section have a higher risk of asthma than those born by vaginal delivery, particularly children of allergic parents. Caesarean section increases the risk for sensitisation to common allergens in children with non-allergic parents only.


  • Funding: This work was supported by the Netherlands Organisation for Health Research and Development, the Netherlands Asthma Foundation and the Netherlands Ministry of Health, Welfare and Sport.

  • Competing interests: None.

  • Ethics approval: The study protocol was approved by the medical ethics committees of the participating institutes and all parents gave written informed consent.