title: Prevalence of asthma symptoms based on the European Community Respiratory Health Survey questionnaire and FENO in university students: gender differences in symptoms and FENO.
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.
  
  
  BACKGROUND
  UMIN000003244.
authors.affiliation: Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi 371-8511, Japan. tamotsui@showa.gunma-u.ac.jp.
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Ishizuka
authors.forename: Shinichi
authors.initials: S
authors.lastname: Matsuzaki
authors.forename: Haruka
authors.initials: H
authors.lastname: Aoki
authors.forename: Masakiyo
authors.initials: M
authors.lastname: Yatomi
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kamide
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hisada
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tsuburai
authors.forename: Kunio
authors.initials: K
authors.lastname: Dobashi
authors.forename: Kihachi
authors.initials: K
authors.lastname: Ohshima
authors.forename: Kazuo
authors.initials: K
authors.lastname: Akiyama
authors.forename: Masatomo
authors.initials: M
authors.lastname: Mori