Non-invasive evaluation of lower airway inflammation in hyper-responsive elite cross-country skiers and asthmatics.
Asthma-like symptoms and bronchial hyper-responsiveness (BHR) to methacholine are prevalent in competitive cross-country skiers. Whether these symptoms (ski asthma) in these athletes are caused by asthma remains uncertain. Bronchial responsiveness to adenosine 5'-monophosphate (AMP) and nitric oxide (NO) concentration in exhaled air, both indirect markers of asthmatic airway inflammation, were investigated in two non-smoking study populations of skiers and asthmatics. Of 18 skiers with ski asthma, 15 non-steroid and 14 steroid-treated asthmatics, BHR to AMP was present in five (28%), six (40%) and 10 (71%) subjects respectively. Although the groups were not significantly different in responsiveness to methacholine, responsiveness to AMP increased in order of magnitude from ski asthma < non-steroid-treated < steroid-treated asthma. Exhaled NO in 44 (nine with ski asthma) skiers was not significantly different from 82 healthy non-atopic controls [median [interquartile range (IQR)] 6.5 (4.1-9.9) vs. 5.2 (4.2-6.5) ppb]. Exhaled NO in 29 subjects with mild intermittent asthma was three-fold greater [median (IQR) 19.2 (5.1-25.6) ppb, P < 0.01] than in skiers. Exhaled NO was two- and four-fold greater in atopic than non-atopic subjects in the skier (P < 0.001) and asthmatic (P < 0.01) groups, respectively, and was correlated to methacholine responsiveness in atopic asthmatics (n = 22, rho = 0.55, P < 0.01). Exhaled NO was not elevated in ski asthma and may be more useful as a marker of atopic status than inflammation in the lower airway in skiers. Few skiers were hyper-responsive to AMP, indicating that pre-activated mucosal mast cells are not a predominant feature in ski asthma.
Sue-Chu
M
M
Department of Lung Medicine, University Hospital, Trondheim, Norway. malcolm.suechu@st.telia.no
Henriksen
A H
AH
Bjermer
L
L
D000249:Adenosine Monophosphate; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001249:Asthma / Q000503:physiopathology*; D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests; D016535:Bronchial Hyperreactivity; D016085:Bronchoconstrictor Agents; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis; D012865:Skiing / Q000502:physiology*; D018709:Statistics, Nonparametric
D015415:Biomarkers; D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D009569:Nitric Oxide; D000249:Adenosine Monophosphate