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OBJECTIVES: To study the prevalence of exercise-induced bronchoconstriction (EIB) and exercise-induced laryngeal obstruction (EILO) in adolescent athletes.

METHODS: All adolescents (n = 549) attending first year at a sports high school in 2016 and 2017, were invited to answer a questionnaire on respiratory symptoms. The 367 responding participants were divided into two groups based on whether they reported exercise-induced dyspnea (dyspnea group) or not (non-dyspnea group). Randomly selected participants in each group were invited to undergo two standardized exercise tests, an EIB test and a continuous laryngoscopy exercise (CLE) test, to investigate EILO.

RESULTS: In total, 98 participants completed an EIB test, 75 of whom also completed a CLE test. Positive EIB tests: eight of 41 in the dyspnea group and 16 of 57 in the non-dyspnea group. Positive CLE tests: five of 34 in the dyspnea group and three of 41 in the non-dyspnea group. The estimated prevalence of EIB was 23.1 % (95 % CI 14.5 - 33.8) and of EILO 8.1 % (95 % CI 2.5 - 18.5) in the whole study population. No differences in prevalence of EIB or EILO were found between the dyspnea and the non-dyspnea groups.

CONCLUSION: EIB was highly prevalent in this cohort of adolescent athletes. EILO was less prevalent, but represents an important differential diagnosis to EIB. Self-reported exercise-induced dyspnea is a weak indicator for both EIB and EILO and standardized testing should be provided.

BACKGROUND: Exercise-induced bronchoconstriction (EIB) and exercise-induced laryngeal obstruction (EILO) are common in elite athletes. Knowledge of which factors are related to incident EIB and EILO is limited. The aim of this study was to explore the course of EIB and EILO in adolescent athletes over a 2 years period and baseline characteristics related to incident EIB.

METHODS: Questionnaire data on respiratory symptoms, asthma, and aeroallergy and results of objective EIB and EILO tests were collected from 58 participants (27 tested for EILO) at baseline and after 2 years (follow-up). Associations between incident EIB and baseline asthma-like symptoms, exercise-induced symptoms, fractional exhaled nitric oxide (FeNO), aeroallergy, and sex were assessed using logistic regression models.

RESULTS: Ten participants had incident EIB, and eight participants had persistent EIB. Five were EIB positive at baseline but negative at follow-up, while 35 participants were EIB negative at both time points. Having incident EIB was associated with reporting waking up with chest tightness (OR = 4.38; 95% CI: 1.06, 22.09). Reporting an increased number of asthma-like symptoms increased the likelihood of incident EIB (OR = 2.78; 95% CI: 1.16, 6.58). No associations were found between exercise-induced symptoms, FeNO, aeroallergy, or sex and incident EIB. Incident EILO was found in three and persistent EILO in two of the 27 participants tested.

CONCLUSION: Two in nine had incident EIB and one eighth had incident EILO, suggesting that recurrent testing for EIB and EILO may be relevant in young athletes. Particularly, EIB-negative athletes reporting multiple asthma-like symptoms could benefit from recurrent EIB testing.

Introduction

The forced oscillation technique (FOT) complements spirometry in assessing lung function, with higher sensitivity to small airway dysfunction. Systemic inflammation is thought to influence lung development and exercise-induced bronchoconstriction (EIB), but its relationship to circulating inflammatory proteins in adolescents is unclear.

Objective

To investigate associations between systemic inflammatory biomarkers and baseline lung function and post-exercise airway responses in adolescents.

Methods

In 143 adolescents (13–15 years) from a population-based cohort, baseline spirometry, FOT, and baseline blood samples were obtained. Participants completed an exercise challenge to assess EIB via changes in forced expiratory volume in 1 s (FEV₁), resistance at 5 Hz (R₅), and reactance at 5 Hz (X₅). Plasma protein levels were measured using the proximity extension assay technique (Olink Target Inflammation and Immune Response panels). Associations with lung function (FEV₁% predicted, R5, and X5 z-scores) and post-exercise responses (∆FEV₁, ∆R5, ∆X5) were analyzed using linear regression with false discovery rate correction. Interaction with atopy was also examined.

Results

Higher plasma levels of C-C motif chemokine 19 (CCL19) were significantly associated with lower FEV₁% predicted and lower X₅ z-scores at baseline, indicating reduced lung function and impaired small airway function. No proteins were associated with post-exercise airway responses after correction. Five proteins showed significant interactions with atopy in relation to EIB.

Conclusion

Elevated CCL19 may reflect systemic inflammatory processes contributing to impaired lung function in early adolescence. The observed atopy-related interactions suggest the need to consider atopy in studies of systemic inflammation and airway physiology.