PREVALENCE OF POSITIVE SKIN PRICK TESTS, ALLERGIC-ASTHMA, AND RHINOCONJUNCTIVITIS IN TEENAGERS IN NORTHERN SWEDEN

The prevalence of positive skin prick tests (SPT) for common allergens and symptoms of allergic rhinoconjunctivitis or asthma was investigat ed in Ume (a) over circle in northern Sweden in 1987. Skin prick tests with 10 allergens common in Sweden and a questionnaire were used to e xamine 1112 teenagers. All subjects with a positive skin prick test or symptoms were interviewed, and they were further investigated by a se rum specific IgE test, a ventilatory lung function test, and a physica l examination. At least one skin prick test was positive in 43% of the subjects. Ninety-three percent had at least one positive skin prick t est to one of the three most common allergens: cat, timothy grass, and birch. The prevalence of current allergic rhinoconjunctivitis was 17% , current allergic asthma 2.8%, and current asthma (both allergic and nonallergic) 6.8%. Multiple logistic regression analysis showed that t he most important risk factors for current asthma were sex (being a gi rl) and atopy. Heredity of asthma or rhinoconjunctivitis and being bor n in the winter (October-March) also increased the risk. In atopic sub jects, having a mother who smoked and heredity of asthma increased the risk. For allergic rhinoconjunctivitis, heredity increased the risk o f getting rhinoconjunctivitis.