Study population
Participants were selected from the EAT and EAT-On studies and informed
consent was obtained. (11) The EAT study reviewed the children at 3
months (3m), 12 months (12m), and 36 months (36m) of age with the
primary outcome being the diagnosis of IgE mediated allergy between 1
and 3 years of age. The EAT-On study was the follow-on study conducted
to establish whether the effects seen at the end of the EAT study
represented a delay in food allergy onset or sustained tolerance. The
EAT-On cohort was seen between ages 7-11 years old.
Allergic status was confirmed by either a positive OFC or based on
clinician-taken history of reaction and SPT>5mm if an OFC
was not conducted. Tolerance was determined by a negative OFC and/or
consumption of peanut regularly in the child’s diet as defined by the
EAT-On study protocol (i.e. at least 3g of peanut protein 3 times in the
last 6 months). If the child was not consuming peanut and OFC was
indeterminate or not available, in the presence of SPT=0 mm they were
also considered not allergic.
Skin prick tests (SPT)
SPT were performed to peanut and aeroallergens on the forearm or back,
using a standardized lancet (ALK-Abello), peanut extract (ALK-Abello),
histamine 10 mg/mL or 50% glycerol, 50% buffered saline. Skin test
sites were measured after 15 minutes as the average of the widest
diameter and perpendicular of the wheal.