BACKGROUND—It is the general impression that the prevalence of asthma has increased during recent decades. A study was undertaken to investigate asthma prevalence, respiratory symptoms, and lung function in young adults in the City of Copenhagen 15 years apart.
METHODS—Men and women aged 20-35 years were sampled from the general population living in a defined area of central Copenhagen. The first examination took place in 1976-8 and comprised 1034 subjects (response rate 67.2%). A new sample comprising 1104 subjects (response rate 62.6%) from exactly the same area was examined 15 years later in 1991-4. All participants answered a questionnaire on respiratory symptoms and diseases and performed spirometric tests with measurement of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC).
RESULTS—The prevalence of self-reported asthma increased from 1.5% in the first survey to 4.8% in the second survey (p