The Association of the Delayed Introduction of Cow's Milk with IgE-Mediated Cow's Milk Allergies.

BACKGROUND: Although exclusive breastfeeding at least 4 to 6 months has been recommended to prevent IgE-mediated cow's milk allergy (IgE-CMA), early introduction of food allergens has received a lot of attention in recent years for the prevention of food allergies. OBJECTIVES: We aimed to determine whether IgE-CMA is associated with a feeding pattern in early infancy. METHODS: In a case-control study, we retrospectively compared the patient background, past history of atopic dermatitis, bronchial asthma, family history of allergic diseases, feeding patterns in early infancy, and the reason for choosing early infancy feeding patterns of patients with IgE-CMA with age- and sex-matched healthy controls using a questionnaire completed by their mothers. To minimize the influence of confounders, we also compared patients with IgE-CMA with those with IgE-mediated egg allergy (IgE-EA). RESULTS: A total of 51 patients with IgE-CMA were compared with 102 controls (1:2 matching) and 32 unmatched patients with IgE-EA. In a multivariable logistic regression analysis, the adjusted odds ratio of delayed (started more than 1 month after birth) or no regular cow's milk formula (less than once daily) was 23.74 (95% CI, 5.39-104.52) comparing the CMA group with the Control group, and 10.16 (95% CI, 2.48-41.64) comparing the CMA group with the EA group. Only 3 (6.5%), 2 (4.8%), and 3 (14.3%) mothers in the CMA group, the Control group, and the EA group chose "To prevent allergic disease" as a reason for choosing exclusive or almost exclusive breastfeeding in the first month of life, respectively. CONCLUSIONS: The early introduction of cow's milk formula is associated with lower incidence of IgE-CMA.