PREVALENCE OF ASTHMA IN YOUNG CROSS-COUNTRY SKIERS IN CENTRAL SCANDINAVIA - DIFFERENCES BETWEEN NORWAY AND SWEDEN

An increased prevalence of asthma in cross-country skiers has been rep orted previously. This study was conducted in order to evaluate the pr evalence of asthma among young, elite cross-country skiers in Trondela g, Norway and Jamtland, Sweden. These two regions in central Scandinav ia have different climates during the winter season, with a coastal ty pe in Trondelag while Jamtland is characterized by a colder, drier, in land type of climate. The study population consisted of 171 skiers (11 8 from Norway, 53 from Sweden). The investigation included an asthma q uestionnaire, spirometry and methacholine provocation testing. The pre valence of self-reported asthma-related symptoms was 46% in Norway and 51% in Sweden. The prevalence of bronchial hyper-responsiveness (BHR) was significantly different between the two regions. In Norway, 14% o f the skiers were hyper-responsive to methacholine compared to 43% in Sweden (P<0.001). Moreover, the estimated prevalence of clinically dia gnosed asthma was 12% in Norway and 42% in Sweden (P<0.001). The self- reported frequency of respiratory allergy was higher in Sweden (32%) t han in Norway (11%). However, on an individual basis, self-reported al lergy did not predict occurrence of asthma or BHR. In conclusion, ther e is a high prevalence of BHR and asthma among young, elite cross-coun try skiers in central Scandinavia, especially in Sweden. Cross-country skiing may be a risk factor for the development of asthma. Longitudin al studies of cross-country skiers, and studies to acquire further kno wledge of the mechanisms involved in the development of asthma are ind icated.