Breast-Feeding Linked to Lower Asthma Risk in Childhood

From Medscape Medical News

Laurie Barclay, MD

July 26, 2011 — Breast-feeding is linked to lower asthma risk in early childhood, according to the results of a prospective cohort study reported online July 20 in the European Respiratory Journal.
"The link of duration and exclusiveness of breastfeeding with asthma-related symptoms during the first 4 years was independent of infectious and atopic diseases," said lead author Agnes M. M. Sonnenschein-van der Voort, MSc, an investigator at Generation R from the Erasmus Medical Center, Rotterdam, the Netherlands, in a news release. "These results support current health policy strategies that promote exclusive breastfeeding for 6 months in industrialised countries. Further studies are needed to explore the protective effect of breastfeeding on the various types of asthma in later life."
The goals of the study were to evaluate the associations of breast-feeding with the risks for development of asthma-related symptoms at preschool age, and to determine whether atopic or infectious mechanisms could explain these associations.
The study sample consisted of 5368 children who were enrolled in a population-based prospective cohort study. Questionnaires were completed for these children regarding information on breast-feeding duration and exclusiveness, and on asthma-related symptoms including wheezing, shortness of breath, dry cough, and persistent phlegm.
During the first 4 years, children who were never breast-fed had overall greater risks of wheezing, shortness of breath, dry cough, and persistent phlegm than children who were breast-fed for 6 months. Odds ratios (ORs) were 1.44 (95% confidence interval [CI], 1.24 - 1.66), 1.26 (95% CI, 1.07 - 1.48), 1.25 (95% CI, 1.08 - 1.44), and 1.57 (95% CI, 1.29 - 1.91), respectively.
Associations for exclusive breast-feeding were similar, and wheezing at 1 and 2 years had the strongest associations per symptom per year. The associations of breast-feeding with asthma-related symptoms were partly explained by lower respiratory tract infections but not by eczema, on the basis of additionally adjusted analyses.
Limitations of this study include possible residual confounders or effect modifiers or the influence of genetic variances, and reliance on self-report for asthma-related symptoms.
"[O]ur results suggest that a short duration of breastfeeding and non-exclusivity are associated with increased risks of the asthma-related symptoms during the first 4 years of life, with the strongest effect estimates during the first two years," the study authors write. "These associations seem to be partly explained by lower respiratory tract infections but not by atopic mechanisms. Further studies are needed to explore the underlying mechanisms and the protective effect of breastfeeding on the various types of asthma in later life."


Eur Respir J. Published online July 20, 2011.