Prevalence of lower airway dysfunction in athletes: a systematic review and meta-analysis by a subgroup of the IOC consensus group on ‘acute respiratory illness in the athlete’

Abstract

ObjectiveTo report the prevalence of lower airway dysfunction in athletes and highlight risk factors and susceptible groups.DesignSystematic review and meta-analysis.Data sourcesPubMed, EBSCOhost and Web of Science (1 January 1990 to 31 July 2020).Eligibility criteriaOriginal full-text studies, including male or female athletes/physically active individuals/military personnel (aged 15–65 years) who had a prior asthma diagnosis and/or underwent screening for lower airway dysfunction via self-report (ie, patient recall or questionnaires) or objective testing (ie, direct or indirect bronchial provocation challenge).ResultsIn total, 1284 studies were identified. Of these, 64 studies (n=37 643 athletes) from over 21 countries (81.3% European and North America) were included. The prevalence of lower airway dysfunction was 21.8% (95% CI 18.8% to 25.0%) and has remained stable over the past 30 years. The highest prevalence was observed in elite endurance athletes at 25.1% (95% CI 20.0% to 30.5%) (Q=293, I2=91%), those participating in aquatic (39.9%) (95% CI 23.4% to 57.1%) and winter-based sports (29.5%) (95% CI 22.5% to 36.8%). In studies that employed objective testing, the highest prevalence was observed in studies using direct bronchial provocation (32.8%) (95% CI 19.3% to 47.2%). A high degree of heterogeneity was observed between studies (I2=98%).ConclusionLower airway dysfunction affects approximately one in five athletes, with the highest prevalence observed in those participating in elite endurance, aquatic and winter-based sporting disciplines. Further longitudinal, multicentre studies addressing causality (ie, training status/dose–response relationship) and evaluating preventative strategies to mitigate against the development of lower airway dysfunction remain an important priority for future research.

The COVID-19 in athletes (COVA) study: a national study on cardio-pulmonary involvement of SARS-CoV-2 infection among elite athletes

“…The high number of athletes with pulmonary involvement in this group highlights the importance of adding primarily spirometry when athletes complain of reduced exercise capacity post-COVID. The prevalence of asthma and airway hyperresponsiveness is known to be high in elite athletes [ 40 ], in our study, 14% (17/121) had self-reported asthma. Of these 17 athletes, nine had cardiopulmonary symptoms or duration of symptoms >7 days.…”

“…However, only one had obstructive lung function at the time of examination, and the remaining 10 athletes with obstructive lung function after COVID-19 were not known to have asthma. The diagnosis of asthma can be difficult to establish, and studies have shown a higher prevalence of airway hyperresponsiveness and asthma (‘lower airway dysfunction’) when using objective testing methodology [ 40 , 41 ]. We have no information on how the diagnosis of asthma had been determined before entering our study, but one possible explanation for the high number of athletes with obstructive lung function could be that they had undiagnosed asthma before the COVID infection.…”

International Olympic Committee (IOC) consensus statement on acute respiratory illness in athletes part 2: non-infective acute respiratory illness

“…A recent systematic review and meta-analysis, specifically commissioned for this IOC consensus statement, re-evaluated the prevalence of LAD in athletes. In this review, studies employing different diagnostic approaches revealed an overall prevalence of LAD in ~20% of athletes 112. The highest prevalence rates were reported in elite-level endurance athletes and in those participating in aquatic and winter-based sports.…”

Diagnosis and management of allergy and respiratory disorders in sport: An EAACI task force position paper

“…Exercise‐induced bronchoconstriction (EIB), in the presence or absence of clinical asthma, refers to the transient narrowing of the lower airways that occurs during, or most commonly following exercise 41,42 . The condition is a key indicator of uncontrolled asthma and often one of the first signs of asthma in children, however, also presents as a distinct clinical entity in approximately one in five otherwise healthy athletic individuals 2 …”

“…Allergy and respiratory disorders are common in young athletic individuals, with an estimated prevalence of up to 40% and 20%, respectively 1,2 . The reason individuals engaging in regular exercise are potentially at greater risk of allergic sensitization remains to be fully established; however, it is thought that an interplay exists between genetic predisposition, neurogenic‐mediated inflammation, epithelial sensitivity and environmental factors associated with regular high‐intensity exercise 3–5 .…”