Toennesen, Louise L2; Porsbjerg, Celeste3; Pedersen, Lars2; Backer, Vibeke3
1 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet2 unknown3 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet
INTRODUCTION: Elite athletes frequently experience asthma and airway hyperresponsiveness (AHR). We aimed to investigate predictors of airway pathophysiology in a group of unselected elite summer-sport athletes, training for the summer 2008 Olympic Games, including markers of airway inflammation, systemic inflammation, and training intensity. METHODS: Fifty-seven Danish elite summer-sport athletes with and without asthma symptoms all gave a blood sample for measurements of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNF-α), completed a respiratory questionnaire, and underwent spirometry. Bronchial challenges with mannitol were performed in all 57 athletes, and 47 agreed to perform an additional methacholine provocation. RESULTS: Based on a physician's diagnosis, 18 (32%) athletes were concluded to be asthmatic. Asthmatic subjects trained more hours per week than the 39 nonasthmatics (median (min-max): 25 h·wk (14-30) versus 20 h·wk (11-30), P = 0.001). AHR to both methacholine and mannitol (dose response slope) increased with the number of weekly training h (r = 0.43, P = 0.003, and r = 0.28, P = 0.034, respectively). Serum levels of IL-6, IL-8, TNF-α, and hs-CRP were similar between asthmatics and nonasthmatics. However, there was a positive association between the degree of AHR to methacholine and serum levels of TNF-α (r = 0.36, P = 0.04). Fifteen out of 18 asthmatic athletes were challenged with both agents. In these subjects, no association was found between the levels of AHR to mannitol and methacholine (r = 0.032, P = 0.91). CONCLUSION: AHR in elite athletes is related to the amount of weekly training and the level of serum TNF-α. No association was found between the level of AHR to mannitol and methacholine in the asthmatic athletes.
Medicine and Science in Sports and Exercise, 2015, Vol 47, Issue 5, p. 914-920