MedWire News: Intervention to increase exclusive breastfeeding does not reduce the number of babies who develop asthma and atopic disease in later childhood, according to data published in the British Medical Journal.
These data are from a large, prospective trial conducted in Eastern Europe comparing prolonged, exclusive breastfeeding with normal practice in 31 maternity units and associated follow-up clinics.
In the promotion of breastfeeding intervention trial (PROBIT), researchers studied more than 17,000 women and their newborn babies.
At 3 months, over 40% of the babies randomly assigned to the intervention group were breastfed exclusively according to recommendations set by the World Health Organization and United Nations Children's Fund. In comparison, just 6.4% of babies in the control group were given breast milk alone.
After an average of 6.5 years of follow-up of over 13,000 children, breast-feeding did not appear to reduce the incidence of asthma or atopy.
The PROBIT investigators, led by Michael Kramer (Montreal Children's Hospital, Quebec), comment: "The experimental group had no reduction in risks of allergic symptoms and diagnosis of positive skin prick tests."
Similar percentages of children in the experimental and control groups had ever wheezed (11% and 9.6%, respectively), had asthma (1.4% and 1.0%) or hay fever (5.4% and 3.8%), a recurrent itchy rash (4.9% and 3.6%), or eczema (1.0% and 1.1%).
Skin prick tests looked at five common allergens - house dust mite, cat dander, birch pollen, mixed northern grasses, and Alternaria. Six centers showed unexpectedly high percentages of children with positive tests, but after Kramer and team excluded these centers from their analysis, children in the intervention group were two to three times more likely than controls to exhibit a positive reaction.
Rather than suggest that breastfeeding increases the risk of atopic disease, however, the team prefers to say that it does not have a protective effect. They comment: "We feel on safer ground inferring no reduction in risk."
These results are likely to further fuel debate on the health benefits of breastfeeding as Kramer and team conclude that they "do not support a protective effect of prolonged and exclusive breastfeeding on asthma or allergy."
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