Allergic rhinoconjunctivitis, eczema, and sensitization in two areas with differing climates

In this 5-year follow-up study we compared the prevalence of allergic rhino conjunctivitis, eczema, and sensitization, in relation to several backgroun d factors, in two Swedish regions (Goteborg and Kiruna). In Goteborg, a cit y on the southwest coast, the climate is mild and humid. Kiruna is a town n orth of the Arctic Circle. Questionnaire replies and results of interviews were collected from all 412 7-8-year-old children of a population-based sam ple (203 in Goteborg and 209 in Kiruna); in addition, 192 children from Got eborg and 205 from Kiruna were skin-prick tested for sensitization to commo n aero-allergens. After 5 years, at 12-13 years of age, almost all of the i nitial study cohort were reinvestigated. At follow-up the prevalence of all ergic rhinoconjunctivitis was 17%, eczema 23%, and sensitization 32%. Aller gic rhinoconjunctivitis and eczema were as common in Goteborg as in Kiruna, whereas sensitization was far more common in Kiruna. Children born during the pollen season had allergic rhinoconjunctivitis less often - and were se nsitized to pollen and animal protein less often - than those born during t he rest of the year. Sensitization to birch pollen. cat protein, and horse protein was less common in children living in Goteborg, the region with the highest frequency of cat ownership and horseback riding, and with the long est birch-pollen season. The girls were more commonly horseback riders but the boys were more often sensitized to horses The results. reinforce our pr evious findings: indoor climate may affect the development of sensitization and allergic diseases, to some extent independently; and if exposure to an tigen is unavoidable, high doses might be better than low doses.