Exercise induced breathing problems in adolescents

Sammanfattning: Experiencing respiratory symptoms in conjunction with exercise is common in children and adolescents and can have a negative impact on daily life. The aim of the thesis was to estimate the prevalence of exercise-induced dyspnoea, exercise-induced bronchoconstriction (EIB) and exercise-induced laryngeal obstruction (E-ILO) in a general adolescent population, and to explore factors associated with EIB.Methods: All 12-13-year-old adolescents in the city of Uppsala (n=3,838) participated in a survey on exercise-induced dyspnoea. A subsample of adolescents who answered the survey, 103 randomly selected adolescents reporting exercise-induced dyspnoea and 47 random adolescents who did not report exercise-induced dyspnoea underwent standardised treadmill exercise tests for EIB and E-ILO. The exercise test for EIB was performed while breathing dry air; a positive test was defined as a decrease ≥10% in FEV1 from baseline. E-ILO was investigated using continuous laryngoscopy during exercise. Health related quality of life (HRQoL), and objectively measured daily physical activity were investigated in those with (n=49) and without (n=91) a positive EIB-test.Results: The prevalence of exercise-induced dyspnoea was 14%, and the estimated prevalence of EIB and E-ILO in the total population was 19.2% and of 5.7%, respectively, with no gender differences. In adolescents with exercise-induced dyspnoea 40% had EIB, 6% had E-ILO, and 5% had both conditions.An increased baseline level of fraction of nitric oxide in exhaled air (FeNO), female gender, and exercise-induced dyspnoea were associated with a positive EIB test. Female adolescents with EIB had lower HRQoL and lower baseline lung function compared to females without EIB. These differences were not observed in male adolescents. There was no difference in time spent in moderate- to vigorous daily physical activity between adolescents with and without EIB.