Objectives: The aims of the study were to establish the prevalence of self-reported allergic rhinitis in an adult Nigerian population and to examine the relationship between asthma and allergic rhinitis.

Methods: We conducted an epidemiological study of adults aged between 18 and 45 years in Ilorin, Nigeria from 2005 to 2006. An adaptation of the European Community Respiratory Health Survey questionnaire was administered by trained assistants to obtain information on demographics, history of nasal allergies, asthma symptoms, and smoking history. The participants also underwent spirometry.

Results: Of the 761 individuals screened, 733 were recruited, giving a participation rate of 96.3%; 441 (60.2%) were men and 292 (39.8%) were women. The prevalence of allergic rhinitis and asthma was 29.6% (n=217) and 14.7% (n=108), respectively. Of the individuals with allergic rhinitis, 31.8% (n=69) had asthma and of those with asthma, 63.9% (n=69) had allergic rhinitis. The mean (SD) age of those with allergic rhinitis was 31 (7.5) years and 65% (n=141) were men. The determinants of asthma in individuals with allergic rhinitis were a family history of asthma (odds ratio [OR], 3.38), a history of smoking (OR, –2.58), high socioeconomic status (OR, 3.82) obesity (OR, 3.32), and wheezing (OR, 250). Lung volumes were reduced in those with both asthma and allergic rhinitis compared to those with allergic rhinitis alone.

Conclusion: Our study revealed a high prevalence of allergic rhinitis in individuals with asthma. It is therefore important to increase awareness of the existence of allergic rhinitis and asthma as a common airway disease to ensure adequate management and control of both conditions.

Key words: Prevalence. Asthma. Allergic rhinitis. Comorbidity. Nigeria.