In this study, the authors investigated whether an intervention to promote prolonged, exclusive breastfeeding could protect against asthma, atopic dermatitis, and low lung function in adolescence.

There were 17 046 infant-mother pairs across 31 Belarusian hospitals enrolled in the study. Mothers had to initiate breastfeeding on admission to the postpartum ward and could not have illnesses contraindicating breastfeeding or severely compromising its success; infants had to be singletons of at least 37 completed weeks’ gestation and 2500 g in birth weight and have an Apgar score of at least 5 at 5 minutes.

This was a cluster randomized trial with a control group of usual care and an intervention group designed to promote prolonged, exclusive breastfeeding. This was the fourth follow-up to the original Promotion of Breastfeeding Intervention Trial in which children at 16 years of age were investigated through physician-conducted skin examinations and spirometry-based lung function (primary outcomes) as well as self-reported asthma and eczema symptoms (secondary outcomes).

On the basis of an examination of 13 557 adolescents (51.5% boys; median age of 16.1 years), 21 (0.3%) children in the intervention group and 43 (0.7%) children in the control group had flexural eczema (−0.4% difference; 95% confidence interval: −0.60% to −0.16%). There was no evidence of a protective effect on self-reported atopic eczema symptoms or asthma outcomes; there was a negative association between intervention and spirometry in a modified intention-to-treat analysis, but this lost significance in subsequent analyses.

An intervention to promote prolonged, exclusive breastfeeding reduced the risk of flexural atopic dermatitis but had no effect on self-reported atopic eczema symptoms, lung function, or other measures of asthma.

Although breastfeeding certainly has many benefits, the extent of the benefit with regard to atopy has been uncertain. This study reveals an effect on flexural atopic dermatitis but not on asthma. It is unclear, however, how significant the difference is (ie, whether the eczema that was present was mild and easily controlled). Although there are certainly still many reasons to breastfeed, for many mothers, this is not always possible (eg, medical conditions, underproduction, or logistical issues), and one could extrapolate from this study that prolonged, exclusive breastfeeding is not necessarily protective against all atopy, which may further play a significant role in counseling on breastfeeding as it relates to food introduction and the risk of developing a food allergy.