INTRODUCTION: Bone health appears to be compromised in many elite male cyclists, while bone health in female, adolescent and retired, elite cyclists remaining largely unexplored. The lack of osteogenic stimuli and low energy availability may predispose elite cyclists to impaired bone health, although clear evidence for this presumption is lacking. In the present study we assessed the prevalence of low bone mineral density (BMD) in male and female elite cyclists at different stages of a professional cycling career, and evaluated potential predictors of low BMD in elite cyclists. METHODS: In this cross-sectional study, 93 male and female early (n=31), advanced (n=42) and post (n=20) career elite cyclists underwent dual-energy X-ray absorptiometry for the assessment of total and regional bone mineral density and body composition. Proposed markers of low energy availability (IGF-1, T3) and bone metabolism (CTX-I, P1NP, 25-hydroxy vitamin D) were assessed in fasted blood samples. Training history and injury prevalence were assessed by a questionnaire, complemented with the bone-specific physical activity questionnaire (BPAQ). Backward stepwise multiple regression analysis was conducted to explore associations between BMD and its potential predictors in early and advanced career (i.e. active career) cyclists. Data are presented as mean±SD. RESULTS: With a Z-score of -0.3±0.8, -1.5±1.0, and -1.0±0.9, low BMD (Z-score <1) of the lumbar spine was prevalent in 27, 68, and 50% of the early, advanced and post-career elite male cyclists, respectively. The lumbar spine Z-scores of -0.9±1.0, -1.0±1.0, and 0.2±1.4 in early, advanced, and post-career elite female cyclists, respectively, indicated low BMD in 55, 45 and 20% of these female subpopulations. Remarkably, 59% of the active career elite cyclists, exceeded the P1NP reference range, while the CTX-I reference range was exceeded by 10% of these cyclists. Furthermore, 25-hydroxy vitamin D levels were inadequate (<50 nmol/L) in 13% of the active career elite cyclists. Statistical analysis revealed that BMI, past fracture incidence, past bone-specific physical activity, 25-hydroxy vitamin D and T3 were associated with lumbar spine BMD Z-score in the final model, F(5, 49) = 8.314, P < 0.001, adjusted R2 = .40. All retained variables significantly contributed (P < 0.05) to the final regression model. CONCLUSION: Low bone mineral density is highly prevalent in elite cyclists, especially in early career females and advanced career males and females. These low BMD values may not fully recover after the professional cycling career, given the high prevalence of low BMD in post-career male cyclists. Exploratory analyses suggest that low BMD is associated with fracture incidence, lack of bone-specific physical activity and low energy availability in active career elite cyclists. Collectively, these findings provide direction for exercise and nutritional strategies to prevent or treat low BMD in elite cyclists.
© Copyright 2022 27th Annual Congress of the European College of Sport Science (ECSS), Sevilla, 30. Aug - 2. Sep 2022. Published by Faculty of Sport Science - Universidad Pablo de Olavide. All rights reserved.