Asthma Incidence in Huelva, Spain at 2 Stages of Life: Childhood and Young Adulthood

Abstract

Few studies have evaluated the incidence of asthma in Spain. Although more children than adults develop asthma every year, no study to date has analyzed the differences in incidence by following 2 age cohorts in the same geographical area. The aim of this study was to determine changes in wheezing, bronchial hyperreactivity, and asthma (in terms of onset, persistence, and remission), changes in forced expiratory volume in 1 second (FEV(1)), and asthma incidence in children (11-16 years) and young adults (20-44 years) in the city of Huelva, Spain. We analyzed data from 2 groups studied for the first time between 1991 and 1993 and for the second time after an average follow-up period of 9 years. In the first period, data came from the Study of Respiratory Diseases in Huelva (714 children) and the European Community Respiratory Health Survey conducted in the city (271 adults). Both groups answered a respiratory symptom questionnaire, underwent spirometry testing, and completed a nonspecific bronchial challenge test with methacholine. In adults, onset was more common than remission for both wheezing (15.7% vs 6.9%, P=.011) and bronchial hyperreactivity (10.1% vs 3%, P=.017), and asthma incidence was 4.76 cases/1000 person-years. In children, there were more new cases than remissions for wheezing, (24.2% vs 4.3%, P=.001), bronchial hyperreactivity (13.9% vs 5.4%, P=.02), and asthma (9.3% vs 3%, P=.004). The incidence rate for asthma was 15.69 cases/1000 person-years in this age group. The annual decrease in lung function (FEV(1)) was highest in adults with wheezing (34.3 mL) and asthma (54.8 mL). There were more new cases of wheezing and bronchial hyperreactivity than remissions in both children and young adults. Children had a 3.3-fold higher incidence of asthma than adults in Huelva.