Consumption of cow's milk formula in the nursery and the development of milk allergy

Abstract Background The effect of the amount of transient cow's milk formula (CMF) consumed during the first days of life on IgE‐cow's milk allergy (IgE‐CMA) is unknown. Methods A cohort of 58 patients with IgE‐CMA was identified from a large scale population‐based study of 13,019 infants followed from birth. A group of 116 infants matched for sex and breastfeeding only duration (beyond the nursery period), and another random group of 259 healthy infants were used as controls. Parents were interviewed and the infants' medical records were searched to assess CMF consumption in the nursery. Results While 96% of the mothers of the 174 infants (58 with Cow's milk allergy and 116 controls) reported on exclusive breastfeeding during the stay in the nursery, CMF consumption was documented in 96 (55%) of the infants. Of those, most (57; 59%) received one to three feedings, 20 (21%) received four to nine feedings, and 19 (20%) received ≥10 feedings. Fewer formula feeds (1–3) were significantly more common in the allergic group than ≥4 feeds (p = 0.0003) and no feeds at all (p = 0.02) compared to controls (n = 116). Of those exclusively breastfed in the nursery, 13/23 allergic infants (57%) introduced CMF at age 105–194 days (the period with highest‐risk for IgE‐CMA) compared to 33/98 (34%) from the random control group (n = 259) (p = 0.04). Conclusions Most infants end up receiving few CMF feeds in the nursery. Transient CMF in the nursery is associated with increased risk of IgE‐CMA.