Blood eosinophil related to maternal allergic rhinitis is associated with the incidence of allergic rhinitis in offspring: COCOA study

OBJECTIVE: The identification of allergic rhinitis (AR) in early life is important for the target of intervention. AR is caused by various environmental factors, including house dust mites. We investigated the relationship between the Dermatophagoides farinae (Der f)-IgE and eosinophil in mothers with AR at delivery and the eosinophil levels and AR incidence in children. METHODS: The study participants were 983 mother–child pairs from the COhort for Childhood Origin of Asthma and Allergic Diseases. AR was diagnosed by a doctor at delivery in mother and at 3 years of age in offspring. The association between eosinophil level and AR was assessed using logistic regression analysis. RESULTS: The Der f-IgE level in mother having AR at delivery was associated with the mother’s eosinophil level, and the mother’s eosinophil level was associated with the child’s eosinophil level both at age 1 and 3. The risk of AR at age 3 in children was increased according to increased eosinophil levels in mothers at delivery and in children both aged 1 and 3 years (adjusted odds ratio [aOR] and 95% confidence interval [CI]: 2.57 [1.14–5.78], 2.28 [1.02–5.13], respectively). The risk of childhood AR at the age of 3 is increased when both mothers and children have high eosiniophils (aOR and 95% CI: 2.62 [1.01–6.79], 1.37 [0.98–1.91]). CONCLUSIONS: Der f-IgE in mothers at delivery was related to eosinophil levels in mothers with AR and higher level of eosinophils in both mother and children was associated with the increased risk of AR incidence at the first 3 years of life of children. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-023-04156-1.