[Epidemiologic aspects of bronchial asthma in childhood]

Bronchial asthma was studied in 813 children subdivided into 5 etiopathogenetic groups by lung function tests performed in the symptomfree "interval phase" of the disease. The patients were followed up for a 5-year period (1980-1984). 56% had continuous perennial asthma, 24% seasonal asthma, 14% infection-induced asthma, 3% psychogenic asthma and 3% exclusively exercise-induced asthma. With regard to functional abnormalities, 32% of patients presented with values within the range of normal, 23% showed pulmonary hyperinflation (FRC greater than 130% predicted), 42% had bronchial obstruction (Raw greater than 130% pred.) and 3% showed restriction of static lung volumes (TLC less than 80% pred.). 91 patients with perennial continuing asthma have been followed up under regular anti-asthmatic treatment over 2 years, during which at least 3 lung function tests have been performed. The study shows that asthmatic children must be evaluated according to the kind and degree of functional abnormalities and within certain age groups. Best improvement after treatment, mainly by inhalation of beta-2-mimetrics and mastcell stabilisators, and partly also by topical steroids, was found in the age groups 8-10 years and 11-13 years respectively. In spite of treatment asthmatic children showed an increase in bronchial constriction in the 5-7 year age group and an increase in pulmonary hyperinflation in the 14-16 age group. These two age groups seem to represent vulnerable periods in the development of childhood asthma which are determinant for the later prognosis.