Asthma at 8 years of age in children born by caesarean section
- C Roduit1,
- S Scholtens2,
- J C de Jongste3,
- A H Wijga1,
- J Gerritsen4,
- D S Postma4,
- B Brunekreef2,5,
- M O Hoekstra6,
- R Aalberse7,8,
- H A Smit1,5
- 1Centre for Prevention and Health Services Research, National Institute for Public Health and the Environment, Bilthoven, The Netherlands
- 2Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
- 3Department of Pediatrics, Division of Respiratory Medicine, Erasmus MC – Sophia, Rotterdam, The Netherlands
- 4Beatrix Children’s Hospital, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
- 5Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
- 6Centre for Paediatric Allergology, Wilhelmina Children’s Hospital, Utrecht, The Netherlands
- 7Sanquin Research, Amsterdam, The Netherlands
- 8Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
- 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;
- 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.