The prevalence of IgE-mediated food allergy is increasing worldwide. However the prevalence of childhood food allergy and early life determinants remain unclear. We determined the prevalence of peanut allergy at age 2 years and both perinatal and postnatal factors associated with the risk of peanut allergy, within a contemporary New Zealand (NZ) birth cohort study.
Growing Up in New Zealand is an ethnically and socio-economically diverse cohort made up of 6853 births from 2009-2010 (11% of all births in NZ over this period). Between late pregnancy and when the children were 2 years old information was collected on child characteristics and their environments. Prevalence of peanut allergy was determined by parental report of doctor diagnosis. Multivariable logistic regression was used to describe the early life factors associated with the presence of peanut allergy.
By age 2 years, 162 (2.6%, 95% CI 2.2-3.0%) cohort children were identified as peanut allergic. The odds of having peanut allergy were increased for boys (OR=1.59, 95% CI 1.13-2.26), children diagnosed with eczema since 9 months (OR=10.72, 95% CI 7.26-16.31), children whose mother had a history of atopic disease (OR=1.40, 95% CI 1.00-1.97), or whose mothers identified as being of Asian ethnicity (OR=2.27, 95% CI 1.48, 3.43).
This is the first study to determine prevalence in a diverse NZ cohort and identify key early determinants. In particular the increased likelihood of a peanut allergy in children born to mothers who identified as Asian may be related to discrete biological and environmental factors, further investigation is needed.