Ishizuka et al. Allergy, Asthma & Clinical Immunology 2011, 7:15 http://www.aacijournal.com/content/7/1/15 Page 3 of 8 Put a notice that asked for participation in this clinical study to 3247 students who underwent physical examinations 643 students Intended to participate and visited our room 640 students Understood this clinical study and signed the consent form 2604 students Did not visit our room 3 students The consent form was incomplete 136 students Others 38 student Expected to have asthma 466 students Expected not to have asthma 584 students Ranged in age from 18 to 24 56 students Others The ROC curve was constructed Prevalence of asthma symptoms were analyzed Figure 1 The flowchart of this clinical study. We explained this clinical study in detail using brochure for 643 students who intended to take part in our clinical study and visited the room. We got the consent forms adequately signed by 640 students. In order to investigate the prevalence of asthma symptoms, we analyzed the information obtained from the ECRHS questionnaire andFENO data in 584 students whose ages were from 18 to 24. the 318 female students, the mean FENO was 31.0 ± 24.0 ppb, and was ≥ 38.0 ppb in 80 (25.2%) of 318 students. FENO levels and the percentage of students whose FENO was ≥ 38.0 ppb were significantly higher in men than in women (p < 0.01, Figure 2). FENO was ≥ 38.0 ppb in 38 (24 men and 14 women) of the 50 students (27 men and 23 women) who had experi- enced wheezing. It was ≥ 38.0 ppb in 7 (3 men and 4 women) of 24 students (5 men and 19 women) who had a nocturnal attack of cough. The percentages of subjects whose FENO was ≥ 38.0 ppb were 76.0% of the subjects who had wheezing and 29.2% of those with a nocturnal attack of cough. The percentage of students whose FENO was ≥ 38.0 ppb was smaller in those who had nocturnal attacks of cough than in those who had experienced wheezing (Figure 3A). The percentage of students whose FENO was ≥ 38.0 ppb in those who had experienced wheezing was 88.9% in men and 60.9% in women; the dif- ference was significant (p < 0.05) (Figure 3B). Although a nocturnal attack of cough was relatively frequent in women, only 4 (21.1%) of 19 female students who had nocturnal attacks of cough had a FENO ≥ 38.0 ppb (Fig- ure 3C). 2. Asthmatic symptoms in University students based on the ECRHS questionnaire Of the 584 students, 77 (13.2%) answered that they had any asthmatic symptoms, including wheezing, a noctur- nal feeling of tightness in the chest, a nocturnal attack of shortness of breath, or a nocturnal attack of cough in the last year (Figure 4A). Thus, the maximum prevalence of asthma symptoms in Gunma University students was 13.2%. Thirty-three (12.4%) of 266 male students and 44 (13.8%) of 318 female students had asthmatic symptoms. The percentage of students who had asthmatic symptoms was not significantly different between men and women. Of the 584 students, 50 (8.6%) reported wheezing, 11 (1.9%) had a nocturnal feeling of tightness in the chest,