Babies who have been breast-fed for 4 months and then receive certain types of hydrolyzed formula have a significantly lower risk of developing atopic dermatitis, compared with those given a cow's milk-based formula after breast-feeding, according to results of a 3-year randomized German study of more than 2,000 babies.
One case of atopic dermatitis (AD) could be averted if 20–25 babies were fed either one of two types of hydrolyzed formulas rather than cow's milk-based formulas. Use of the hydrolyzed formulas did not affect the incidence of asthma, however.
“The preventive effect [against AD] developed in the first year and persisted into the third year, indicating real disease reduction rather than postponement of disease onset,” wrote the researchers, led by Dr. Andrea von Berg from the pediatrics department at Marien-Hospital, Wesel, Germany.
“Although it remains controversial whether breast-feeding reduces the risk for allergy in high-risk infants, breast-feeding is the gold standard for infant nutrition,” they wrote. “It was therefore not the goal of our study to question this gold standard and show that hydrolyzates are worse or better. Instead, we wanted to evaluate, in case of formula feeding (for whatever reason), which formula would be the best alternative to reduce the risk for (allergic manifestations).”
The researchers enrolled 2,252 infants who had at least one parent or sibling with an atopic syndrome. The infants were randomized into groups fed one of three hydrolyzed formulas (extensively hydrolyzed casein formula and partially or extensively hydrolyzed whey formula). An observational arm of 889 babies exclusively breast-fed was also included (J. Allergy Clin. Immunol. 2007;119:718–25).
Infants were exclusively breast-fed during the first 4 months, with the introduction of solid food postponed until after 4 months. Researchers tracked diagnoses of AD, urticaria, food allergies, and asthma.
After 3 years, 904 babies on formula and 543 babies in the breast-feeding arm remained in the study population.
Compared with those in the cow's milk-based formula group, infants fed the partially hydrolyzed whey formula (odds ratio 0.57) and those fed the extensively hydrolyzed casein formula (odds ratio 0.43) demonstrated at 1 year a significantly reduced risk of developing any of the allergic manifestations studied, after adjustment for family history of AD and asthma, sex, and maternal smoking.
By the third year, that effect was gone for allergic conditions as a whole, but the protective effect persisted to 3 years for AD. The 3-year cumulative risk of developing AD was lower in children fed the partially hydrolyzed whey formula (odds ratio 0.60) and those fed extensively hydrolyzed casein formula (odds ratio 0.53), compared with those in the cow's milk-based formula group.
Analyzing outcomes based on family history, the only significant effect identified was among those with a family history of AD who were fed extensively hydrolyzed casein formulas; such babies were at lower risk of AD than those given cow's milk-based formula (odds ratio 0.53).
“This is indeed the first study to suggest that the allergic phenotype in the family rather than a biparental family history modifies the effect of nutritional intervention and may be considered when deciding which hydrolyzate should be given,” the researchers wrote. On an intention-to-treat basis, feeding 20 infants extensively hydrolyzed casein formula and 25 partially hydrolyzed whey formula averts a single case of AD. In the smaller group with a family history of AD, the numbers were 11 and 51, respectively.