Prevalence of allergic rhinitis and asthma in Poland in relation to pollen counts

Introduction
Despite the known role of pollen allergens in causing allergy symptoms in sensitized individuals, there are few publications investigating the relationship between pollen exposure in different regions and the prevalence of inhalant allergy.

Aim
To assess the association between the prevalence of allergic rhinitis and asthma and the degree of exposure to pollen in various regions of Poland.

Material and methods
Completed questionnaires of 9,443 subjects living in four urban centres (Wroclaw, Katowice, Warsaw, Bialystok), collected within part of the ECAP project, were analyzed. Children aged 6–7 (n = 2 278), adolescents aged 13–14 (n = 2 418), and adults aged 20–44 (n = 4 747) constituted 24.2%, 25.6% and 50.3% of the respondents, respectively. The clinical part (including skin prick tests, an assay of Timothy grass-specific IgE), was attended by 24% of the respondents. Data from 6-year pollen monitoring served to characterize birch and grass pollen seasons.

Results
We found insignificant negative associations between the duration of birch pollen season and the prevalence of declared allergic rhinitis and asthma during the season across all age groups. There were insignificant inverse associations between the number of days with above-threshold and high grass pollen concentrations, total grass pollen count and the prevalence of declared allergic rhinitis and asthma during the season across all age groups. Associations noted in the clinical part were also non-significant; however, these trends were not uniform across the age groups.

Conclusions
Our findings do not confirm the hypothesis of a positive association between pollen exposure and the prevalence of allergic rhinitis and asthma.