Early life environmental exposure in relation to new onset and remission of allergic diseases in school children: Polish Mother and Child Cohort Study.

Background: This study was based on data from the Polish Mother and Child Cohort Study. Objective: The aim was to study associations between home environment factors and allergic diseases at 1 year of life and new onset and remission of children's allergy diagnosis at ages 7-9 years. Methods: Children's health status was assessed at ∼12 months of age and then at ages between 7-9 years by using a questionnaire administered to the mothers. Children were assessed by pediatrician/allergists. The patients, who were 7-9 years old, underwent skin-prick tests. Exposure to tobacco smoke was evaluated with a questionnaire addressed to parents and/or caregivers and cotinine measurements were taken of mother's saliva during pregnancy and in children's urine at ages 7-9 years. Incidence and remission were calculated by comparing symptoms in the first year of life with symptoms at 7-9 years. We studied the associations among demographic data, home environment, and new onset and remission of food allergy, atopic dermatitis, and asthma and allergic rhinitis in logistic regression analysis. All associations were adjusted for independent risk factors of dependent variables. Results: Data from 211 participants were included in the analysis. During the first year of life, food allergy was the most common symptom (39%), followed by atopic dermatitis (35%) and asthma (12%). When comparing diagnoses at ages 7-9 years with the first year of life, food allergy had decreased by as much as 18.6%, atopic dermatitis decreased by as much as 23.8%, and asthma decreased by as much as 8%, whereas asthma and allergic rhinitis had increased from 6% to 14.8%. More frequent house cleaning negatively correlated with the new onset of atopic dermatitis and of asthma and allergic rhinitis. Hypersensitivity to seasonal allergens and mites and to any other allergen positively correlated with new onset of food allergy, atopic dermatitis, and asthma and allergic rhinitis. Parental atopy positively correlated with the new onset of asthma and negatively correlated with asthma remission. Conclusion: Analysis of our findings indicated that new onset and/or remission of allergic diseases was linked with hypersensitivity to house-dust mites in children who were polysensitized and with parental atopy. In addition, children who had food allergy, allergic rhinitis, or atopic dermatitis at the age of 1 year had more of a chance developing other atopic disease (except asthma) at ages 7-9 years and less of a chance of having a remission of the disease.