Association Between Breastfeeding and Childhood Breathing Patterns: A Systematic Review and Meta-Analysis

Objectives: This systematic review aimed to evaluate the association between breastfeeding and breathing patterns in children. Materials and Methods: We searched PubMed, EMBASE, Web of Science, CINAHL, and the Cochrane Central Register of Controlled Trials for publications from inception to October 1, 2017. The breastfeeding duration and period of exclusive breastfeeding were selected as primary outcomes. The odds ratio (OR) and 95% confidence interval (CI) were calculated. A meta-analysis was conducted to synthesize the evidence. The Newcastle-Ottawa Score was used for quality and comparability assessment. Results: Of the 54 articles identified, three observational studies met the inclusion criteria for this meta-analysis, representing 1,046 participants. The results of the meta-analysis revealed that the prevalence rate of mouth breathing (OR=2.04; 95% CI, 1.26-3.31; p=0.004) was significantly higher in subjects who were breastfed for less than 6 months, but no significant difference was observed within the periods of exclusive breastfeeding (6 months or less) (OR=1.27; 95% CI, 0.73-2.21; p=0.40). Conclusion: We found only limited evidence about the association between breastfeeding and breathing patterns. However, the current evidence supports the association between breastfeeding and childhood breathing patterns. Based on this review, we found that the frequency of normal nasal respiration increases with the duration of breastfeeding. The methodological quality of the studies included was moderate. Thus, future studies should aim to correct the confounding factors related to breathing patterns, to use standardized diagnostic criteria of mouth breathing, and to conduct a prospective research to reduce the recall bias.