The prevalence of asthma in adult population of southwestern Iran and its association with chronic rhinosinusitis: a GA(2)LEN study

BACKGROUND: Asthma is recognized as a major public health concern in the world. The aim of this investigation was to evaluate the prevalence of asthma by using the Global Allergy and Asthma Network of Excellence (GA(2)LEN) questionnaire and examine its association with chronic rhinosinusitis, in the province of Bushehr, Southwestern of Iran. METHODS: In a cross-sectional, population-based study, a total of 5420 invited individuals, aged 15–65, were selected through a multi-stage, stratified, cluster random sampling and from which 5201 completed the GA(2)LEN questionnaire (response rate = 95.9%). The prevalence of asthma, current, and physician-diagnosed asthma were analyzed by using sex and age groups and the association of asthma and chronic rhinosinusitis (CRS) was investigated using a multiple logistic regression model. RESULTS: Based on the information from the GA(2)LEN questionnaire, the overall prevalence of asthma in the population under study was 10.0% (95% CI 9.2–10.8). Moreover, the prevalence of current asthma was 8.9% (95% CI 8.1–9.7). Further, the prevalence of current early, late-onset and physician-diagnosed asthma within the asthma group was 51.1% (95% CI 46.5–55.7), 48.9% (95% CI 44.3–53.5) and 3.9% (95% CI 2.1–2.5), respectively. Additionally, CRS was more frequent among the participants with asthma [(57.3%, OR = 2.3; 95% CI 2.1–2.5)], and there was a significant association between CRS and current, early and late-onset of asthma (P < 0.001; OR = 4.4, 3.2 and 6, respectively). CONCLUSION: This large population study conducted in the southwestern part of Iran suggests that the prevalence of asthma is high. Moreover, the result of this study showed a strong association of asthma with CRS; also after adjusting for sex, age, educational level, and smoking.