Breastfeeding and Lung Function of Children: A Systematic Review and Meta-Analysis.

Aim: To evaluate the associations between breastfeeding and lung function among children without known respiratory diseases and to determine the effects of breastfeeding on spirometry.

Methods: A systematic search of PubMed, Embase and Cochrane was performed from their inception to 11 Oct 2023 (PROSPERO identifier: CRD42023471664). Observational studies (cohort or cross-sectional or case-control design) and randomised controlled trials (RCTs) were searched. A random-effects model meta-analysis was used to estimate the effect size if significant heterogeneity was detected (p < 0.05 or I² > 50%); Otherwise, the fixed-effects model was applied.

Results: In total, 13 observational studies with 18 152 children were included in the qualitative synthesis, and five studies with 5305 children were included in the meta-analysis. Compared to children who were never breastfed, those who were breastfed had better FEV1 (β: 19.34 mL; 95% CI: 6.05, 32.64; p = 0.004) and PEF (β: 87.50 mL/s; 95% CI: 27.43, 147.58; p = 0.004). A similar trend was observed for FVC (β: 17.45 mL; 95% CI: -0.43, 35.33; p = 0.06). Furthermore, compared to children breastfed for less than three to four months, those breastfed for three to four months or more had better FEV1 (β: 19.86 mL; 95% CI: 4.21, 35.51; p = 0.01), FVC (β: 31.90 mL; 95% CI: 7.87, 55.93; p = 0.009) and PEF (β: 75.68 mL/s; 95% CI: 24.40, 126.97; p = 0.004).

Conclusion: This systematic review and meta-analysis revealed associations between breastfeeding and improved lung function in children aged 6-16 years. Further high-quality evidence is needed.