Ishizuka et al. Allergy, Asthma & Clinical Immunology 2011, 7:15 http://www.aacijournal.com/content/7/1/15 R E S E A R C H ALLERGY, ASTHMA & CLINICAL IMMUNOLOGY Open Access Prevalence of asthma symptoms based on the European Community Respiratory Health Survey questionnaire and FENO in university students: gender differences in symptoms and FENO Tamotsu Ishizuka1*, Shinichi Matsuzaki1, Haruka Aoki1, Masakiyo Yatomi1, Yosuke Kamide1, Takeshi Hisada1, Takahiro Tsuburai2, Kunio Dobashi3, Kihachi Ohshima4, Kazuo Akiyama2 and Masatomo Mori1 Abstract Background: The fractional concentration of nitric oxide in exhaled air (FENO) is used as a biomarker of eosinophilic airway inflammation. FENO 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 FENO 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 FENO 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 FENO to make the diagnosis of asthma, the sensitivity was 86.8% and the specificity was 74.0%. FENO was ≥ 38.0 ppb in 32.7% of students. FENO was higher in men than in women. The prevalence of asthma symptoms estimated by considering FENO was 7.2%; the prevalence was greater in men (9.4%) than women (5.3%). A FENO ≥ 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 FENO levels as well as subjective symptoms. Gender differences were observed in both FENO levels and asthma symptoms reflecting the presence of eosinophilic airway inflammation. Trial registration number: UMIN000003244 Background Bronchial asthma is a chronic inflammatory disease char- acterized by reversible airway limitation and airway hyper- reactivity. Clinically, patients with asthma have repeated symptoms, such as wheeze, shortness of breath, or cough, especially at night or early morning. When we make a * Correspondence: tamotsui@showa.gunma-u.ac.jp 1Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi 371-8511, Japan Full list of author information is available at the end of the article diagnosis of asthma, it is helpful to expect that the patients have eosinophilic airway inflammation although asthma is not always associated with eosinophilic inflammation. In recent years, the fractional concentration of nitric oxide in exhaled air (the fraction of exhaled nitric oxide, FENO) has been used as a biomarker of eosinophilic inflammation in the airway [1-3]. In fact, FENO is increased in asthmatic patients compared to healthy subjects [4]. Measurements of FENO are useful for making the diagnosis of asthma, and its sensitivity and specificity as a marker for the diag- nosis are relatively high [5-8]. There are two procedures © 2011 Ishizuka et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.