Skin prick tests and specific IgE in adults from three different areas of Sweden

Abstract

The aims of this part of the European Respiratory Health Survey were to estimate the prevalence of atopic sensitization to inhalant allergens among adults in three different areas of Sweden and to investigate the association between sensitization and certain risk factors. Randomly selected subjects aged 20-46 years from Goteborg, Uppsala, and Vasterbotten were investigated with the skin prick test (SPT), analyses for specific IgE antibodies in serum (specific IgE) and total serum immunoglobulin E (total IgE), and a questionnaire. SPT was performed in 1572 subjects and analyses of specific IgE in 1470. One or more positive SPT were found in 35.6% and one or more positive specific IgE in 31.7% -approximately the same values in all three areas. Birch, grass, cat, and dog were the most frequent sensitizing agents and occurred at similar prevalences, i.e., around 1S%, in all areas. The SPT to mite was positive in 14.1% in Goteborg, 7.4% in Uppsala, and 7.9% in Vasterbotten. A positive SPT to pellitory of the wall (Purietarin), not described previously in Sweden, was found in 3.4% in Goteborg. Living in Goteborg was independently associated with a higher risk of a positive SPT to mite and Purieturiu. Heredity, male sex, and low age were independently associated with atopy. Birth in the Scandinavian countries was independently associated with sensitization to cat, whereas birth in other countries was associated with sensitization to mite. The overall prevalence of atopy was similar in the three Swedish areas, but the sensitizing allergens varied. There is an indication that sensitization is increasing in the population, as low age was associated with sensitization. Sensitization to cat, but not to mite, appears to be particularly important 1 in persons born in the Scandinavian countries.Atopy, the tendency to develop IgE antibodies to common allergens, is associated with asthma, allergic rhinoconjunctivitis, and eczema. Atopy is in part due to genetic susceptibility (1). Studies from several countries (2-9) reveal an increasing prevalence of atopic diseases, indicating that exposure to environmental factors plays an important role. Furthermore, some studies reveal a geographic variation in the occurrence of asthma (10-12). Aberg (11) and Aberg et al. (12) found higher prevalences in the north of Sweden than in the south. It is not known whether these regional differences are caused by a difference in the prevalence of atopic sensitization itself, or by an increasing and geographically variable susceptibility in sensitized persons to develop clinical disease. P.

The European Community Respiratory Health Survey: what are the main results so far?

“…The prevalence of atopic sensitization was also negatively associated with age. This was found in analyses of local data [38,46], as well as in an analysis of the combined ECRHS data set [47]. The level of total IgE was also negatively related to age [47].…”

“…The effect of immigration has so far only been reported in one paper. In an analysis of data from the Swedish centres, no difference was found in the prevalence of atopic sensitization in subjects born in the Nordic countries compared to those who were not [38]. The prevalence of sensitization to mite, ragweed and Cladosporium was higher and the prevalence of sensitization to birch and cat lower in subjects not born in the Nordic countries.…”

“…In one study, this sex difference was explained by difference in airway geometry between females and males [55], while in other studies the prevalence of BHR remained higher in females, even after adjustment of airway calibre [52,53]. A higher risk of sensitization to at least some allergens was found in males than in females in several analyses of local data sets [32,38,46,56]. This was also confirmed in an analysis of the combined ECRHS data set where JARVIS et al [47] found that males were more likely to be sensitized to house dust mite and grass than females, while no sex difference was found in sensitization to cat.…”

Allergy markers in respiratory epidemiology

“…Surprisingly, skin test reactivity depends also on the period of the survey. House dust mite reactivity was more frequent in subjects seen during the winter compared to the others [104]. Finally, it is well known that various medications may reduce the skin tests reactivity.…”

“…In general, there is no agreement on the role played by sex in skin test reactivity according to the literature. Some studies did not ®nd any difference [103], others did ®nd one [102,104], even if only in some age groups [9]. Few endogenous factors have been related to skin test reactivity.…”