Risk factors for asthma symptoms at school age: An 8-year prospective study

Abstract

Childhood recurrent wheezing is a very prevalent heterogeneous clinical entity. An 8-year prospective study was performed to correlate the clinical outcome of recurrent wheezing in the first years of life with prognostic risk factors. A cohort of 308 children with recurrent wheezing, aged <7 years, were enrolled in 1993, studied using a questionnaire, skin-prick tests, and serum total IgE. According to the study protocol, in 1996 and 2001, the cohort was assessed. In 2001, 81% of the initial sample was reevaluated (n=249); 61% remained symptomatic. Prevalence of atopy was 48% in 1993, 65% in 1996, and 75% in 2001. By logistic regression analysis, we identified the following as independent risk factors for asthma symptoms in the last year of the follow-up: personal history of rhinitis (odds ratio [OR] = 15.8, 95% confidence interval [CI], 6.1-40.8; p < 0.001), paternal asthma (OR =, 7.2; 95% CI = 1.7-29.7; p = 0.007), personal history of atopic dermatitis (OR = 5.9, 95% CI = 2.2-15.7; p < 0.001), maternal asthma (OR = 5.4, 95% CI = 1.7-17.1; p = 0.004), allergen sensitization (OR = 3.4, 95% CI = 1.2-10.4; p = 0.03), and onset of symptoms in the 2nd year or later in preschool-aged children (OR = 2.1, 95% CI = 1.1-4.8; p = 0.04). Kindergarten attendance before 12 months was identified as a protective factor (OR = 0.4, 95% CI = 0.2-0.9; p = 0.04). Among the 128 nonatopic children in 1993, 52% developed allergen sensitization. We identified as prognostic risk factors for asthma symptoms personal history of allergic disease, parental asthma, atopy, and late onset of symptoms. In a significant number of children clinical symptoms can occur years before allergen sensitization.