Breastfeeding and risk of childhood asthma: a systematic review and meta-analysis

Objective To investigate the relationship between breastfeeding and the development of pediatric asthma.

Methods A systematic review and meta-analysis was conducted with MEDLINE, EMBASE, CINAHL and ProQuest Nursing and Allied Health source databases. Retrospective/prospective cohorts in children <18 years old with breastfeeding exposure reported were included. The primary outcome was a diagnosis of asthma by a physician or using a guideline-based criterion. A secondary outcome was asthma severity.

Results Forty-two studies met inclusion criteria. Thirty-seven studies reported the primary outcome of physician/guideline-diagnosed asthma, and five studies reported effects on asthma severity. Children with longer duration/more breastfeeding compared to less have a lower risk of asthma (OR=0.84; 95% CI: 0.75–0.93, I²=62.4%). Similarly, a lower risk of asthma was found in children who had more exclusive breastfeeding versus less exclusive breastfeeding (0.81; 0.72–0.91, I²=44%). Further stratified analysis of different age groups demonstrated a lower risk of asthma in the 0–2 age group (0.73; 0.63–0.83) and the 3–6 age group (0.69; 0.55–0.87), there was no statistically significant effect on the 7+ age group.

Conclusion The finding suggests that the duration and exclusivity of breastfeeding are associated with a lower risk of asthma in children less than seven years of age.