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.