Background Methacholine hyperresponsiveness is prevalent in elite athletes. Comparative studies have hitherto been limited to methacholine, eucapnic voluntary hyperpnoea and exercise. This study investigated airway responsiveness to these stimuli as well as to adenosine 5′-monophosphate (AMP) and mannitol, in 58 cross-country ski athletes.
Methods Exhaled nitric oxide concentration (FENO), spirometry and bronchial challenge in random order with methacholine, AMP and mannitol were consecutively performed on three study days in the autumn. Specific IgE to eight aeroallergens and a self-completed questionnaire about respiratory symptoms, allergy and asthmatic medication were also performed on day 1. Eucapnic voluntary hyperventilation (EVH) and field exercise tests were randomly performed in 33 of the skiers on two study days in the following winter.
Results Of 25 (43%) skiers with airway hyperresponsiveness (AHR), 23, five and three skiers were hyperresponsive to methacholine, AMP and mannitol, respectively. Methacholine hyperresponsiveness was more prevalent in subjects without asthma-like symptoms. The FENO was not significantly different in skiers with and without methacholine hyperresponsiveness. Four of 14 skiers with and four of 19 skiers without methacholine hyperresponsiveness were hyperresponsive to EVH or exercise challenge. AHR to any stimulus was present in 16 asymptomatic and nine symptomatic skiers. Asthma-like symptoms were not correlated with AHR to any stimulus.
Conclusions Methacholine hyperresponsiveness is more common in asymptomatic skiers and is a poor predictor of hyperresponsiveness to mannitol and hyperpnoea. The low prevalence of hyperresponsiveness to indirect stimuli may suggest differences in the pathogenesis of methacholine hyperresponsiveness in elite skiers and non-athletes.
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Funding MS-C was financially supported as a post-doctoral research fellow by the Norwegian Research Council. The study was also supported by a study grant from Glaxo SmithKline, Norway.
Competing interests None for MS-C, NC and LB. SDA is the inventor of the mannitol test. The intellectual property is owned by Sydney South West Area Health Service (SSWAHS) and the commercial rights are licensed to Pharmaxis Ltd (Frenchs Forest, NSW, Australia). SDA and JDB own shares in Pharmaxis Ltd, which they purchased themselves but they have not received options. SDA and JDB each receive a 10% share of the royalties paid to SSWAHS.
Ethics approval This study was conducted with the approval of the Regional Ethics Committee in Trondheim.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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