Breastfeeding during the first 27 weeks of life had a risk-specific effect on reducing respiratory symptoms in healthy term infants, based on data from a prospective cohort study of 436 children in Switzerland.

“Breastfeeding is generally accepted to be protective against respiratory symptoms in early life,” but most published studies on this topic are cross-sectional and more likely biased, wrote Dr. Olga Gorlanova of the University of Basel (Switzerland) and her colleagues.

The researchers studied infants enrolled in the Bern-Basel Infant Lung Development cohort via weekly telephone interviews during the first year of life. In addition, weekly measurements of environmental particulate matter were collected from local monitoring stations. Risk factors included maternal history of atopy, vaginal vs. cesarean delivery, parents’ level of education, smoking during and after pregnancy, number of older siblings, child care attendance, and housing conditions.

Overall, infants breastfed during the first 27 weeks of life had significantly reduced respiratory symptoms, compared with nonbreastfed infants (risk ratio, .70)

The study “suggests that breastfeeding attenuates the effects of risk factors such as sex, age, gestational age, cesarean delivery, and prenatal maternal tobacco smoking in healthy term infants,” Dr. Gorlanova and her associates wrote. No significant interaction was noted between breastfeeding and child care attendance, number of older siblings, maternal atopy, or environmental particulate matter.

Read the full study here ( J Pediatr. 2016. doi: 10.1016/j.jpeds.2016.03.041 ).