Background and objective As caesarean delivery and childhood allergy continue to rise, their inter-relationships may change. We examined whether caesarean delivery predicts allergic disease and impaired lung function in two contemporary harmonised population-based cohorts.
Methods Parent-reported asthma and eczema data were drawn from two prospective Australian infant cohorts, HealthNuts (n=5276, born 2006–2010) and the Longitudinal Study of Australian Children (LSAC, n=5107, born 2003–2004) at age 6–7 years, and spirometric lung function from LSAC’s Child Health CheckPoint (n=1756) at age 11–12 years. Logistic regression estimated associations between delivery mode and current asthma and eczema at 6–7 years, and linear regression examined lung function at 11–12 years. Models were adjusted for potential confounding factors.
Results Complete case analysis included 3135 HealthNuts and 3654 LSAC children (32.2% and 30.9% born by caesarean, respectively). An association was evident between caesarean delivery and asthma at age 6–7 years in HealthNuts (adjusted OR (aOR) 1.25, 95% CI 1.00 to 1.57) but not in LSAC (aOR 1.05, 95% CI 0.86 to 1.28), while neither study showed clear associations with eczema (HealthNuts: aOR 1.09, 95% CI 0.88 to 1.35; LSAC: aOR 0.89, 95% CI 0.69 to 1.15). Spirometric lung function parameters at age 11–12 years were similar by delivery mode. Associations were not modified by duration of breast feeding, maternal history of asthma/eczema, childcare attendance, number of older siblings or pet exposure.
Conclusions In two unselected populations using harmonised protocols, the likely association of caesarean delivery with developing childhood allergy was small.
Statistics from Altmetric.com
MW and RLP are joint senior authors.
Contributors MW, RLP and KEL conceptualised and designed the study, supervised data analyses, and reviewed and revised the manuscript. DB, SR, SCD, A-LP, MLKT, KJA, AJL, JEM and JJK critically reviewed and revised the manuscript. ZL conceptualised and designed the study, carried out the initial analyses, drafted the initial manuscript, and reviewed and revised the manuscript. All authors critically reviewed the manuscript for interpretation, intellectual content and approved the final manuscript as submitted. All authors agree to be accountable for all aspects of the work.
Funding This paper uses unit record data from Growing Up in Australia, the LSAC. The study is conducted in partnership between the Australian Department of Social Services (DSS), the Australian Institute of Family Studies (AIFS) and the Australian Bureau of Statistics (ABS). The Child Health CheckPoint was supported by the Australian National Health and Medical Research Council (NHMRC, Project Grants 1041352 and 1109355), the Royal Children’s Hospital Foundation (2014-241), the Murdoch Children’s Research Institute, the University of Melbourne, the National Heart Foundation of Australia (100660), Financial Markets Foundation for Children (2014-055, 2016-310) and the Victoria Deaf Education Institute. HealthNuts was supported by the NHMRC (Project Grants 491233 and 1006215), Ilhan Food Allergy Foundation, AnaphylaxiStop and the Charles and Sylvia Viertel Medical Research Foundation. DB, KJA, RLP, JJK, A-LP, AJL, SCD and MW hold or held NHMRC fellowships during data collection for this paper. DB holds a National Heart Foundation of Australia Honorary Future Leader Fellowship (100369). Research at the Murdoch Children’s Research Institute is supported by the Victorian Government's Operational Infrastructure Support Programme. The researchers were independent of the funders.
Patient consent for publication Not required.
Ethics approval HealthNuts was approved by the Victorian State Government Office for Children (CDF/07/492) and Department of Human Services (10/07), and the Royal Children’s Hospital Human Research Ethics Committee (27047 and 32294); LSAC was approved by the Australian Institute of Family Studies Ethics Committee; and CheckPoint was approved by the Royal Children’s Hospital Human Research Ethics Committee (HREC33225) and the Australian Institute of Family Studies Ethics Committee (AIFS14-26).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement The LSAC datasets and technical documents are available to researchers at no cost via a licence agreement. Data access requests are coordinated by the National Centre for Longitudinal Data. More information is available at https://dataverse.ada.edu.au/dataverse/lsac. HealthNuts data are not publicly avaiblable but can be requested.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.