Prevalence and characteristics of exercise-induced asthma in children

Abstract

We have evaluated the prevalence and the characteristics of exercise-induced asthma (EIA) in a group of 71 patients with a prior history of mild, moderate or severe asthma (42 males and 29 females), aged 6-16 years-old. Measurements of the forced expiratory volume in 1 second (FEV1) were obtained before and at regular intervals up to 8 hours following exercise. As a control, the same patients were evaluated at similar time intervals on another day when they had not been submitted to an exercise challenge. Using pre-exercise FEV1 values as the reference, 32 patients (45.1%) had a positive exercise challenge, defined as a fall in FEV1 value equal to or greater than 15% from baseline following exercise. Among the patients with a positive exercise challenge, the majority (23/32, 71.8%) had an immediate response alone, with no significant changes in FEV1 within the 8-hour follow-up. However, a subgroup of patients (9/32, 28.1%) had both an immediate and a late-phase response to exercise. During the control day, no significant fall in FEV1 were observed. in keeping with previous investigations, no correlation was found between a history of EIA and a positive exercise challenge in the present study. Positive exercise challenges were found more frequently among patients with moderate and severe asthma than patients with mild asthma.Universidade Federal de São Paulo, Dept Pediat, Div Allery & Clin Immunol & Rheumatol, UNIFESP,EPM, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pediat, Div Allery & Clin Immunol & Rheumatol, UNIFESP,EPM, São Paulo, BrazilWeb of Scienc