The gender, age and risk factor distribution differs in self-reported allergic and non-allergic rhinitis: a cross-sectional population-based study

BACKGROUND Few population-based studies have assessed the prevalence and the risk factors of non-allergic rhinitis (NAR) in comparison to allergic rhinitis (AR). Moreover, epidemiologic data on rhinitis in the elderly subjects and in southern Europe are scarce. OBJECTIVE This study aimed at estimating the prevalence and at comparing the risk factor distribution of AR and NAR in a general population sample aged 20-84 years in Italy. METHODS A questionnaire on respiratory symptoms and risk factors was administered to random samples of the Italian population aged 20-44 (n = 10,494) 45-64 (n = 2167) and 65-84 (n = 1030) in the frame of the Gene Environment Interactions in Respiratory Diseases (GEIRD) study. Current AR and NAR were defined according to the self-reported presence of nasal allergies or of nasal symptoms without a cold or the flu. RESULTS NAR showed a significant descending pattern in females from 12.0 % (95 % CI 11.1, 13.1) in the 20-44 year age class, to 7.5 % (5.4, 10.3) in the 65-84 year age class (p = 0.0009), and a roughly stable pattern in males, from 10.2 % (9.3, 11.2) to 11.1 % (8.4, 13.9) (p = 0.5261). AR decreased from 26.6 % (25.7, 27.6) in 20-44 years age class to 15.6 % (13.3, 18.0) in the 65-84 years age class (p < 0.0001), without gender difference. Subjects living near industrial plants and ex- and current smokers had a higher risk of NAR. Current smokers had a lower risk and subjects living in a Mediterranean climate a higher risk of AR. CONCLUSION AR and NAR are fairly distinct conditions, as they have a different age, gender and risk factor distribution.