Does Breastfeeding Reduce Eczema Risk In Teenagers? ...Maybe

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​Jen Thompson, MPH

Asthma and eczema are among the most common diseases of childhood; they’re also atopic (allergic) diseases, meaning they’re associated with an overactive immune system.  Risk for these conditions is inherited – children whose parents have asthma, eczema, food allergies or hay fever are more likely to develop these conditions themselves -- but there is also evidence that environment, in addition to genetics, influences this risk.

Children people who live on farms or in rural areas tend to have lower rates of atopic disease than people who live in more urban areas. This may be because children in rural areas tend to have more siblings and more contact with pets or farm animals, which may prime their immune systems to be less sensitive to allergens as they grow older. 

​In addition, the World Health Organization (WHO) and other health authorities recommend 4 to 6 months of exclusive breastfeeding to help protect against atopic disease. The evidence that breastfeeding helps prevent asthma and eczema, however, is mixed.  One large recent study found no association between breastfeeding and eczema.  Parental history of atopy seems to be a major influence; one meta-analysis found that, for children with no family history of atopic disease, breastfeeding had no effect on whether the children later developed eczema. A family history may, in fact, lead to reverse causality; mothers worried about asthma or eczema may nurse their babies for longer, creating the impression that breastfeeding does not prevent or may even contribute to later atopic disease. Many studies on this topic also rely on participants’ self-reported histories of breastfeeding, asthma and eczema, which may be subject to memory bias.

In a paper published in JAMA Pediatrics, we examined whether breastfeeding influences a child’s later risk of developing asthma or eczema.  To do so, we reviewed data from PROBIT, the PROmotion of Breastfeeding Intervention Trial, a cluster-randomized clinical trial. We enrolled 17,046 children born in 1996 and 1997 at 31 Belarusian hospitals, half of which had been randomized to follow the WHO’s Baby-Friendly Hospital Initiative.  At these hospitals, the staff were trained to provide education and support to help new mothers breastfeed their babies.  The other hospitals followed their usual practices.  We collected extensive data from the children and their mothers during the first year of their lives; on average, babies born at the intervention hospitals were breastfed more exclusively (i.e., without the use of formula or other supplemental foods) and for longer than the children born at the control hospitals. At the most recent PROBIT study visit, when the children were around age 16.5, we collected data from 13,557 adolescents, including a clinical exam to determine whether they had signs of eczema (also called atopic dermatitis), their lung capacity, and whether they had ever been diagnosed with asthma. 

​We found that children in the PROBIT intervention group had a 54% lower risk for eczema at their PROBIT study visit.  Among the children born at the PROBIT intervention hospitals, 0.3% (21 of 7064) had eczema at their 16.5 year PROBIT visit, compared to 0.7% (43 of 6493) of the children born at the control hospitals.  This protective effect was present even when we considered other factors in our analysis, including whether their parents had an atopic disease, whether they lived in an urban or rural area, their age, whether they were male or female, their weight at birth, and their gestational age.  We did not find any difference between the two groups of children’s lung function or their history of asthma.

However, it’s also important to note that the experience of a specific subset of children in Belarus – which has low rates of asthma, eczema and atopic disease – may not match that of children in other parts of the world.  Although there are limitations to the findings, this study adds to the published research that suggests that early life experiences influence later disease risk, even decades after those exposures took place.