Prevalence of asthma symptoms based on the European Community Respiratory Health Survey questionnaire and F E NO in university students: gender differences in symptoms and F E NO

摘要

Background The fractional concentration of nitric oxide in exhaled air (F E NO) is used as a biomarker of eosinophilic airway inflammation. F E NO is increased in patients with asthma. The relationship between subjective asthma symptoms and airway inflammation is an important issue. We expected that the subjective asthma symptoms in women might be different from those in men. Therefore, we investigated the gender differences of asthma symptoms and F E NO in a survey of asthma prevalence in university students. Methods The information about asthma symptoms was obtained from answers to the European Community Respiratory Health Survey (ECRHS) questionnaire, and F E NO was measured by an offline method in 640 students who were informed of this study and consented to participate. Results The prevalence of asthma symptoms on the basis of data obtained from 584 students (266 men and 318 women), ranging in age from 18 to 24 years, was analyzed. Wheeze, chest tightness, an attack of shortness of breath, or an attack of cough within the last year was observed in 13.2% of 584 students. When 38.0 ppb was used as the cut-off value of F E NO to make the diagnosis of asthma, the sensitivity was 86.8% and the specificity was 74.0%. F E NO was ≥ 38.0 ppb in 32.7% of students. F E NO was higher in men than in women. The prevalence of asthma symptoms estimated by considering F E NO was 7.2%; the prevalence was greater in men (9.4%) than women (5.3%). A F E NO ≥ 38.0 ppb was common in students who reported wheeze, but not in students, especially women, who reported cough attacks. Conclusions The prevalence of asthma symptoms in university students age 18 to 24 years in Japan was estimated to be 7.2% on the basis of F E NO levels as well as subjective symptoms. Gender differences were observed in both F E NO levels and asthma symptoms reflecting the presence of eosinophilic airway inflammation. Trial registration number UMIN000003244