Effect of breastfeeding duration on lung function at age 10 years: a prospective birth cohort study
- 1Department of Epidemiology and Biostatistics, Norman J Arnold School of Public Health, University of South Carolina, USA
- 2David Hide Asthma and Allergy Research Centre, St Mary’s Hospital, Isle of Wight, and University of Southampton, Southampton, UK
- 3College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
- Dr I U Ogbuanu, Department of Epidemiology and Biostatistics, Norman J Arnold School of Public Health, University of South Carolina, 800 Sumter Street, Columbia, SC 29208, USA;
- Received 7 May 2008
- Accepted 7 September 2008
- Published Online First 10 November 2008
Introduction: The protective effects of breastfeeding on early life respiratory infections are established, but there have been conflicting reports on protection from asthma in late childhood. The association of breastfeeding duration and lung function was assessed in 10-year-old children.
Methods: In the Isle of Wight birth cohort (n = 1456), breastfeeding practices and duration were prospectively assessed at birth and at subsequent follow-up visits (1 and 2 years). Breastfeeding duration was categorised as “not breastfed” (n = 196); “<2 months” (n = 243); “2 to <4 months” (n = 142) and “⩾4 months” (n = 374). Lung function was measured at age 10 years (n = 1033): forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio and peak expiratory flow (PEF). Maternal history of asthma and allergy was assessed at birth. The effect of breastfeeding on lung function was analysed using general linear models, adjusting for birth weight, sex, current height and weight, family social status cluster and maternal education.
Results: Compared with those who were not breastfed, FVC was increased by 54.0 (SE 21.1) ml (p = 0.001), FEV1 by 39.5 (20.1) ml(p = 0.05) and PEF by 180.8 (66.1) ml/s (p = 0.006) in children who were breastfed for at least 4 months. In models for FEV1 and PEF that adjusted for FVC, the effect of breastfeeding was retained only for PEF (p = 0.04).
Conclusions: Breastfeeding for at least 4 months enhances lung volume in children. The effect on airflow appears to be mediated by lung volume changes. Future studies need to elucidate the mechanisms that drive this phenomenon.
Funding: This study was funded in part by the National Institutes of Health R01 AI061471. The 10-year follow-up of this study was funded by National Asthma Campaign, UK (Grant No 364).
Competing interests: None.
Ethics approval: The local research ethics committee approved the study.