Asthma in elite athletes: how do we manage asthma-like symptoms and asthma in elite athletes?

Introduction: Asthma is frequent in elite athletes and the high prevalence of asthma might be associated with specific types of sport. It has been suggested that chronic endurance training might increase the number of neutrophils in the airways, and this may reflect airway injury. The use of anti-asthmatic medication in elite athletes is also currently under scrutiny in order to reduce the risk of under-treatment or over treatment.

Objectives: Determine the use of anti-asthmatic medication and the prevalence of asthma-like symptoms and asthma in Danish elite athletes. Further, to determine whether elite athletes with asthma-like symptoms have asthma and investigate the airway inflammation and airway reactivity to mannitol.

Materials And Methods: Three cross-sectional studies: (i) Applications for Abbreviated Therapeutic Use Exemption (ATUE) certificates in 2005 were studied (N = 694); (ii) a questionnaire survey of elite athletes (N = 418); and (iii) a clinical study of elite athletes. A total of 54 elite athletes (19 with physician-diagnosed asthma) participated together with two control groups: (i) 22 non-athletes with physician-diagnosed asthma (steroid naïve for 4 weeks before the examination) and (ii) 35 non-athletes without asthma.

Examinations: questionnaires, exhaled nitric oxide (eNO), spirometry, skin prick test, mannitol test and blood samples. Induced sputum was done in subjects with asthma.

Results: (i) Anti-asthmatic medication was included in 445 (64%) of all ATUE certificates. A total of 308 (69%) elite athletes applied for inhaled corticosteroids (ICS), and most ATUE certificates were handled by general practitioners (GP) (78%). (ii) A total of 329 (79%) elite athletes completed the questionnaire; 181 (55%) reported asthma-like symptoms and 46 (14%) had asthma. Anti-asthmatic medication was currently taken by 24 (7%) elite athletes. Elite athletes participating in endurance sports had higher prevalences of asthma-like symptoms (74%), use of anti-asthmatic medication (15%) and current asthma (24%) than all other athletes (P < 0.01). (iii) No difference in lung function, eNO, airway reactivity (AR) to mannitol and atopy between elite athletes with and without asthma-like symptoms was found. Elite athletes with physician-diagnosed asthma had less AR [Response Dose Ratio (RDR) 0.02 (0.004) vs 0.08 (0.018) P < 0.01], and fewer sputum eosinophils [0.8% (0-4.8) vs 6.0% (0-18.5), P < 0.01] than non-athletes with physician-diagnosed asthma.

Conclusion: Most applications for ATUE certificates were handled by GPs, and the majority concerned anti-asthmatic medication. We found signs of under-treatment of elite athletes with asthma, and endurance athletes had the highest prevalence of asthma-like symptoms and asthma. The prevalence of asthma-like symptoms was higher than the prevalence of asthma, and we showed that symptoms alone should not be used to diagnose asthma. We demonstrated that asthma-like symptoms are independent of lung function, eNO, RDR and atopy in elite athletes. Elite athletes with physician-diagnosed asthma seem to have less airway reactivity and fewer sputum eosinophils than non-athletes with physician-diagnosed asthma, but more studies are needed to further investigate if and how the asthma phenotype of elite athletes differs from that of classical asthma.