PURPOSE OF THE STUDY.
To determine if the early introduction of cow’s milk (CM) formula was either positively or negatively associated with the development of an IgE-mediated cow’s milk allergy (IgE-CMA).
Patients were recruited at Ryugasaki Saiseikai Hospital in Japan. The study included 51 children with IgE-CMA (defined as having had immediate allergic reactions within 2 hours of ingestion, a CM IgE level ≥0.7 kUA/L, and diagnosis by a board-certified allergy specialist) and 102 age- and sex-matched controls seen for the common cold or routine vaccination without having a CMA or other food allergy. An additional 32 unmatched patients with an IgE-mediated egg allergy (egg-IgE >0.7 kUA/L and diagnosis by a specialist) and without a milk-related food allergy were also included. All patients were older than 1 year of age at the time of enrollment.
This was a retrospective case-control study of pediatric patients recruited from November 2014 to February 2015. A standardized questionnaire was completed by the parents and included information regarding past histories of allergic diseases, family history of allergic diseases, time of introduction of nonregular (not used daily) CM formula, time of introduction of regular (used daily) CM formula, feeding patterns in the first month of life and reason for choosing those patterns, and timing of discontinuation of CM formula and reason for discontinuation. Feeding patterns in the first month of life were categorized as (1) exclusive breastfeeding with no formula; (2) almost exclusive breastfeeding with CM formula less than daily; (3) mixed, feeding predominantly with breast milk but with CM formula at least once a day; (4) mixed, feeding predominantly with CM formula; and (5) exclusive CM formula and no breast milk.
The rates of atopic dermatitis and bronchial asthma were significantly higher in the CMA group (P < .001 and P = .12, respectively). The CMA group also showed increased maternal age at delivery, paternal asthma, paternal rhinitis, maternal asthma, maternal food allergy, and decreased pet ownership (P < .05). Compared with the egg-allergic group, the CMA group showed significantly higher rhinitis and maternal asthma (P < .05). Exclusive breastfeeding was significantly higher in the CMA group, whereas early regular CM formula feeding (once daily within the first month of life) and early regular continuous CM formula feeding (once daily within the first month of life and continued until 6 months or until the onset of CMA) were significantly higher in the controls. In a multivariable logistic regression analysis that controlled for allergic symptoms, parental age at delivery, and family history of allergic diseases, the adjusted odds ratio of delayed (started 1 month after birth) or no cow’s milk formula (less than once daily) was 23.74 (95% CI, 5.39–104.52) for the CMA group compared with the controls and 10.16 (95% CI, 2.48–41.64) compared with the egg-allergic group. The odds ratio of CMA versus control was even higher when looking at no early regular continuous CM formula feeding (92.76 [95% CI, 9.05–951.04]).
Early (starting in the first month of life) and regular (daily) exposure to CM is protective against the development of IgE-mediated CMA.
This relatively small study supports the hypothesis that early ingestion of an allergen may be protective against the development of a food allergy. The general notion is supportive of a previous study on the early introduction of peanuts to prevent peanut allergy, although that trial introduced peanuts at 4 up to 11 months of age (Du Toit G et al, N Engl J Med. 2015;372:803–813). There are limitations to this current study. The study was retrospective, and maternal recall can be inaccurate. The study does not delineate the time after initial exposure to regular ingestion of CM formula nor the amounts ingested. There may be an optimal time from initial exposure to regular introduction. A study by Katz Y et al (J Allergy Clin Immunol. 2010;126:77–82) noted a window during which early regular consumption (in the first 14 days) was protective of IgE-CMA, but rates were also lower for any age other than introduction from 105–194 days. Randomized trials will be needed to better understand the role of very early introduction of CM, especially as this broaches the topic of exclusive breastfeeding.
- Copyright © 2017 by the American Academy of Pediatrics