Exercise-induced bronchospasm among students of Tehran University of Medical Sciences in 2004

Exercise-induced bronchospasm (EIB) is a clinical syndrome that affects 8-20% of the general population and 11-50% of athletes. Although a variety of testing protocols for the diagnosis of EIB have been pursued, the optimal algorithm still is lacking. The aim of this study was to determine the prevalence of EIB among students of Tehran University of Medical Sciences and to find out whether self-reported symptoms are sufficient to establish the diagnosis of EIB. A total of 463 students completed an EIB symptoms-specific questionnaire, followed by a 9-minute exercise test. Spirometric measurements were performed before, and 6 and 15 minutes after exercise. In our study, decrements of >15% in forced expiratory volume in 1 second or 25% in peak expiratory flow or forced expiratory flow at 25-75% from baseline values were defined as positive indications of EIB. The overall prevalence of EIB was 10.8% (15.94% in men versus 8.62% in women; p = 0.02). There was no significant difference between the students with and without EIB regarding body mass index, family income, and allergy frequency. The frequency of at least two out of the four symptoms of coughing, wheezing, shortness of breathing, and chest pain/discomfort among students with EIB was significantly higher than those without EIB (26.5% versus 15.1%, respectively; p = 0.04). The sensitivity and specificity of self-reported symptoms for EIB diagnosis were 26.5 and 84.9%, respectively. Although among all determinants proposed for EIB, respiratory symptoms are closely related to the disease, diagnosis based on only these symptoms is not recommended because of high false positive and false negative results.