HIGH PREVALENCE OF ASTHMA AND RELATED SYMPTOMS IN TEENAGERS IN NORTHERN SWEDEN

Recent reports have suggested an increased asthma prevalence in the No rdic countries. The prevalence of asthma and related symptoms from low er airways in Umea, Northern Sweden, was investigated in 1987. We used a questionnaire and a skin prick test in 1,112 teenagers. Individuals with symptoms or positive skin prick tests were examined further. The clinical examination included an interview, a ventilatory lung functi on test, serum specific immunoglobulin E (IgE) test, and a physical ex amination. Individuals, with symptoms from the lower airways underwent a methacholine inhalation test. Asthma was defined as recurrent attac ks of dyspnoea and/or wheezing, triggered by known stimuli (excluding infections), and at least one of the following: signs of obstructive a irways at examination or provocation concentration giving a 20% fall i n forced expiratory volume in one second (PC20) <8 mg.ml-1. Using this definition, the prevalence of asthma was 6.8%, with a significantly h igher prevalence in girls (9.6%) than in boys (4.1%). Furthermore, 16. 4% had dyspnoea, wheeze or prolonged cough but did not fulfil our crit eria for asthma. The prevalence of asthma and of symptoms from lower a irways is higher than has previously been found in Sweden.