Prolonged breastfeeding may protect against bronchiolitis development during the first two years of life in developed countries, according to a new research letter published in ERJ Open Research.
Researchers analysed standardised questionnaire data on breastfeeding duration and respiratory symptoms of 4,040 children to try to quantify the protective effect of breastfeeding against respiratory tract infections (RTIs) during the first 2 years of life.
Unadjusted and adjusted logistic regression was used to determine which RTIs were affected by breastfeeding duration; adjusted models controlled for sex, ethnicity, socioeconomic status, perinatal factors, environmental factors, and parental history of asthma, hay fever and bronchitis.
Of the 4,040 included children, 1,659 had never been breastfed, 1,639 had been breastfed for ⩽6 months, and 742 for >6 months.
Respiratory symptom data suggested there was limited evidence of a protective effect of breastfeeding against RTIs including frequent colds, croup or pneumonia during the first 2 years of life, and there was no modification due to sex for any RTIs.
After adjusting for confounding factors, only breastfeeding for >6 months remained protective against bronchiolitis; a further sensitivity analysis on subjects with exact breastfeeding information (2,286 children) also found evidence for a protective effect of breastfeeding against bronchiolitis, appearing to confirm the finding.
The authors note that a key limitation to this study was the lack of information on the exact dates of infections and insufficient knowledge of the severity of infections.