Prevalence of exercise-induced bronchoconstriction and exercise-induced laryngeal obstruction in a general adolescent population.
BACKGROUND
Exercise-induced respiratory symptoms are common among adolescents. Exercise is a known stimulus for transient narrowing of the airways, such as exercise-induced bronchoconstriction (EIB) and exercise-induced laryngeal obstruction (EILO). Our aim was to investigate the prevalence of EIB and EILO in a general population of adolescents.


METHODS
In this cross-sectional study, a questionnaire on exercise-induced dyspnoea was sent to all adolescents born in 1997 and 1998 in Uppsala, Sweden (n=3838). A random subsample of 146 adolescents (99 with self-reported exercise-induced dyspnoea and 47 without this condition) underwent standardised treadmill exercise tests for EIB and EILO. The exercise test for EIB was performed while breathing dry air; a positive test was defined as a decrease of ≥10% in FEV1 from baseline. EILO was investigated using continuous laryngoscopy during exercise.


RESULTS
The estimated prevalence of EIB and EILO in the total population was 19.2% and 5.7%, respectively. No gender differences were found. In adolescents with exercise-induced dyspnoea, 39.8% had EIB, 6% had EILO and 4.8% had both conditions. In this group, significantly more boys than girls had neither EIB nor EILO (64.7% vs 38.8%; p=0.026). There were no significant differences in body mass index, lung function, diagnosed asthma or medication between the participants with exercise-induced dyspnoea who had or did not have a positive EIB or EILO test result.


CONCLUSIONS
Both EIB and EILO are common causes of exercise-induced dyspnoea in adolescents. EILO is equally common among girls and boys and can coexist with EIB.
Department of Neuroscience/Physiotherapy, Uppsala University, Uppsala, Sweden.
Henrik
H
Johansson
Surgical Sciences: Otolaryngology and Head & Neck Surgery, Uppsala University, Uppsala, Sweden.
Katarina
K
Norlander
Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.
Lars
L
Berglund
Medical Sciences, Uppsala University, Uppsala, Sweden.
Christer
C
Janson
Medical Sciences, Uppsala University, Uppsala, Sweden.
Andrei
A
Malinovschi
Women's and Children's Health: Pediatrics, Uppsala University, Uppsala, Sweden.
Lennart
L
Nordvall
Surgical Sciences: Otolaryngology and Head & Neck Surgery, Uppsala University, Uppsala, Sweden.
Leif
L
Nordang
Department of Neuroscience/Physiotherapy, Uppsala University, Uppsala, Sweden.
Margareta
M
Emtner
D000293:Adolescent; D001250:Asthma, Exercise-Induced / Q000453:epidemiology* / Q000209:etiology; D016084:Bronchoconstriction; D002648:Child; D003430:Cross-Sectional Studies; D005080:Exercise Test / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007826:Laryngismus / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D015995:Prevalence; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology