PREVALENCE OF ATOPY AND POLLINOSIS IN THE ADULT-POPULATION OF SWITZERLAND (SAPALDIA STUDY)

The Swiss SAPALDIA study is a large multicenter cross-sectional study initiated in 1991 to evaluate the relationship between environment and respiratory symptoms and diseases in adults, and included subjects from eight areas in Switzerland with distinctive environmental characteristics. We present here prevalence data for atopy, pollinosis and atopic asthma obtained from a random sample of 8,357 adults (18-60 years) assessed by standardized computer-based interview as well as by allergy skin prick tests (SPTs) (performed with Phazet) to grass, birch and Parietaria pollen, house dust mite, cat and dog epithelia and the moulds Alternaria and Cladosporium and by an in vitro allergy screen test (Phadiatop CAP FEIA system). On the basis of a positive Phadiatop (total 28.9%; males 32.9%, females 25.0%; p < 0.001) and/or a positive SPT (total 23%; males 25.0%, females 20.8%; p < 0.001), 32.3% of the study population were considered atopic (males 35.7%, females 28.8%; p < 0.001). Concerning the prevalence of skin sensitization (SPT wheal greater than or equal to 3 mm), the highest rate was observed for grass (12.7%), followed by house dust mite (8.9%), silver birch (7.9%), cat (3.8%) and dog (2.8%), whereas moulds and Parietaria elicited less than 1% positive SPTs. The prevalence of atopic rhinitis (rhinitis symptoms associated with atopy) was 13.5% (males 14.3%, females 12.6%; p < 0.05) and the prevalence of current hay fever varied between 9.1% (questionnaire answer and a positive SPT to at least one pollen), 11.2% (questionnaire answer and presence of atopy) to 14.2% (questionnaire answer only) with no significant difference by sex. However, a significant difference for the prevalence rate of hay fever was observed between Swiss citizens with 11.6% and foreign citizens living in Switzerland with 8.7% (p < 0.01). Pollen-induced asthma (seasonal asthma symptoms and presence of a positive SPT to pollen) was judged to be present in at least 4.3%. These data confirm the high rate of atopy and atopic respiratory diseases in a western country. Taking into consideration the main differences in prevalence rates recorded in 1926 (0.82%), 1958 (4.8%) and 1986 (9.6%), the present survey demonstrates a further increase in self-reported current hay fever in Switzerland.