Asthma and atopy: How much is it really attributable? About a representative population of Tunis

Abstract

Introduction: In recent decades it has become routine to describe asthma as an atopic disease. We carried out this study to evaluate the prevalence of asthma and assess the association of atopy with asthma in individuals and in population.

Method: A cross-sectional survey, single pass, representative of the general population was carried out in subjects aged from 2 to 50 years. Informed consent was obtained. Prevalence was determinate through questionnaires, validated and used in international surveys, corresponding to the asthma screening and lung function test. Definition of atopy was based on clinical symptoms of rhinitis and allergy skin. Statistical analysis was performed using SPSS 18.0.

Results: The study included 4470 subjects. There was 40.2% male and 59.8% female. Current asthma prevalence was 6.8% in adults and 5.9% in children. Lung function test showed reversibility in 20%. The proportion of asthma cases that are “attributable” to atopy (defined as rhinitis and allergy skin) was estimated by the “population attributable risk”. About 53.5% of children and 43.8% of adults with asthma have suffered from rhinitis (OR=3.8, p<0,001). Positive correlation was also found between asthma and skin allergy: (15.8% versus 5.8% OR=3.5, p<0.001). There was no significant difference between adult and children in neither between male nor female.

Conclusions: There is evidence of an association of the prevalence of atopy with the prevalence of asthma. Higher estimation can be obtained by using skin allergy tests and total serum IgE witch will be the purpose of the phase 2 of our study.