A summary of studies on the prevalence of EILO in athletes and adolescents
| Prevalence of EILO in athletes | ||||||
| Authors | Year | Population | Design | Findings | Diagnostic method | Comments |
| Morris et al 5 | 1999 | 105 patients with exertional dyspnoea at an army clinic | Cross-sectional Prospective | 12% had VCD | Laryngoscopy before and after exercise | Selected population |
| Rundell and Spiering29 | 2003 | 370 Olympic-level athletes | Cross-sectional Prospective | 30% had EIB 5% had stridor (of whom 52% had EIB) | Auscultation | Olympic-level athletes |
| Hanks et al30 | 2012 | 148 athletes referred for exertional dyspnoea | Retrospective chart review | 52% EIB 14% Asthma 70% VCD 31% EIB + VCD | Laryngoscopy after exercise | Selected population |
| Nielsen et al 4 | 2013 | 91 athletes referred for CLE testing. 88 tested | Retrospective chart review | 35% had EILO 43% had Asthma | Continuous laryngoscopy during exercise | Highly selected population |
| Turmel et al 31 | 2015 | 352 Athletes, 42 suspected EILO, 12 examined | Cross-sectional Prospective | 12 tested and 12 confirmed EILO | Laryngoscopy during eucapnic voluntary hyperventilation | Selected population, heterogenous evaluation |
| Heffler et al 32 | 2015 | 37 healthy elite rowers without exertional dyspnoea | Cross-sectional Prospective | 27% had EIB, 43% had EILO, 16% both | Flow volume loop assessment during eucapnic voluntary hyperventilation | Vit D lower in those with EILO |
| Irewall et al 6 * | 2021 | 89 invited elite cross-country skiers | Cross-sectional Prospective | 27% had EILO 38% had asthma (of whom 29% had EILO) | Continuous laryngoscopy during exercise | Well-designed. Risk of underestimated results |
| Prevalence of EILO in adolescents | ||||||
| Christensen et al 2 | 2011 | 556 invited. 150 tested for AHR, 17.6% tested for EILO | Cross-sectional Prospective | AHR in 28% of invited. EILO in 42% of tested, 7.6% of total invited Six persons had both AHR and EILO | Continuous laryngoscopy during exercise | |
| Johansson et al 1 | 2015 | 3838 invited, 2309 responded, symptoms in 330 85 with and 42 without symptoms tested | Cross-sectional Prospective | 11% had EILO 40% had EIB Estimated EILO prevalence 5.7%. Similar in boys and girls | Continuous laryngoscopy during exercise | Well-designed |
| Ersson et al 3 * | 2020 | 549 first-year high-school athletes invited 42 with and 34 without dyspnoea tested | Cross-sectional Prospective | EIB in 8/41 with and 16/57 without dyspnoea EILO in 5/34 with and 3/42 without dyspnoea Estimated prevalence of EILO 8.1% | Continuous laryngoscopy during exercise (on bike) | Self- reported symptoms are week indicators for both EIB and EILO |
*Studies published after conducting the systematic search.
AHR, airway hyper-responsiveness; CLE, continuous laryngoscopy exercise; EIB, exercise-induced bronchoconstriction; EILO, exercise-induced laryngeal obstruction; VCD, vocal cord dysfunction.