Eimear Dolan1, Alina Dumas2, Karen M Keane3, Giulia Bestetti2, Luisa Helena Mavalli Freitas2, Bruno Gualano2,4, Wendy M Kohrt5, George A Kelley6, Rosa Maria Rodrigues Pereira7, Craig Sale8, Paul A Swinton9. 1. Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, Av. Dr. Arnaldo, 455, 3º andar, São Paulo, SP, 01246-903, Brazil. eimeardol@gmail.com. 2. Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, Av. Dr. Arnaldo, 455, 3º andar, São Paulo, SP, 01246-903, Brazil. 3. Department of Sport, Exercise and Nutrition, Galway Mayo Institute of Technology, Galway, Ireland. 4. Food Research Centre, University of São Paulo, São Paul, SP, Brazil. 5. Department of Medicine, Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA. 6. Department of Epidemiology and Biostatistics, West Virginia University, Morgantown, WV, USA. 7. Bone Metabolism Laboratory, Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, SP, Brazil. 8. Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, UK. 9. School of Health Sciences, Robert Gordon University, Aberdeen, UK.
Abstract
BACKGROUND: Circulating biomarkers are often used to investigate the bone response to an acute bout of exercise, but heterogeneity in factors such as study design, quality, selected biomarkers, and exercise and participant characteristics render it difficult to synthesize and evaluate available evidence. OBJECTIVE: The aim of this study was to quantify the effects of an acute exercise bout on bone biomarkers, along with the influence of potential moderators such as participant, exercise, and design characteristics, using a systematic review and meta-analytic approach. METHODS: The protocol was designed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines and prospectively published. Seven databases were systematically searched in accordance with predefined eligibility criteria. Bayesian three-level hierarchical meta-analysis models were used to explore the main effects of acute exercise on bone biomarkers, as well as potential moderating factors. Modelled effect sizes were interpreted according to three metrics, namely (1) evidence of an effect (defined by whether, or how much of, the credible interval [CrI] included zero); (b) the size of that effect (threshold values of 0.01, 0.2, 0.5 and 0.8 were used to describe effect sizes as very small, small, medium and large, respectively); and (c) the level of certainty in the estimated effect (defined using the GRADE framework). RESULTS: Pooling of outcomes across all designs and categories indicated that an acute bout of exercise increased bone resorption (ES0.5 0.10, 95% CrI 0.00-0.20) and formation (ES0.5 0.05, 95% CrI 0.01-0.08) markers but the effects were very small and highly variable. Furthermore, moderator analyses revealed the source of some of this variability and indicated that exercise type and impact loading influenced the bone resorptive response. A moderate increase in C-terminal telopeptide of type 1 collagen (CTX-1) was observed in response to cycling (ES0.5 0.65, 95% CrI 0.20-0.99), with greater durations and more work leading to larger CTX-1 increases. CTX-1 response peaked within 15 min and 2 h after the exercise bout. Other exercise types did not influence CTX-1. Changes to all bone formation markers were very small and transient, with the very small increases returning to baseline within 15 min of exercise cessation. No major trends for bone formation markers were identified across any of the moderating categories investigated. Certainty of evidence in most outcomes was deemed to be low or very low. CONCLUSION: The large influence of an acute bout of prolonged cycling on the bone resorption marker CTX-1, alongside the lack of a response of any biomarker to resistance or high-impact exercise types, indicate that these biomarkers may be more useful at investigating potentially osteolytic aspects of exercise, and raises questions about their suitability to investigate the osteogenic potential of different exercise types, at least in the short term and in response to a single exercise bout. Certainty in all outcomes was low or very low, due to factors including risk of bias, lack of non-exercise controls, inconsistency, imprecision and small-study effects. PROTOCOL REGISTRATION AND PUBLICATION: This investigation was prospectively registered on the Open Science Framework Registry ( https://osf.io/6f8dz ) and the full protocol underwent peer review prior to conducting the investigation.
BACKGROUND: Circulating biomarkers are often used to investigate the bone response to an acute bout of exercise, but heterogeneity in factors such as study design, quality, selected biomarkers, and exercise and participant characteristics render it difficult to synthesize and evaluate available evidence. OBJECTIVE: The aim of this study was to quantify the effects of an acute exercise bout on bone biomarkers, along with the influence of potential moderators such as participant, exercise, and design characteristics, using a systematic review and meta-analytic approach. METHODS: The protocol was designed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines and prospectively published. Seven databases were systematically searched in accordance with predefined eligibility criteria. Bayesian three-level hierarchical meta-analysis models were used to explore the main effects of acute exercise on bone biomarkers, as well as potential moderating factors. Modelled effect sizes were interpreted according to three metrics, namely (1) evidence of an effect (defined by whether, or how much of, the credible interval [CrI] included zero); (b) the size of that effect (threshold values of 0.01, 0.2, 0.5 and 0.8 were used to describe effect sizes as very small, small, medium and large, respectively); and (c) the level of certainty in the estimated effect (defined using the GRADE framework). RESULTS: Pooling of outcomes across all designs and categories indicated that an acute bout of exercise increased bone resorption (ES0.5 0.10, 95% CrI 0.00-0.20) and formation (ES0.5 0.05, 95% CrI 0.01-0.08) markers but the effects were very small and highly variable. Furthermore, moderator analyses revealed the source of some of this variability and indicated that exercise type and impact loading influenced the bone resorptive response. A moderate increase in C-terminal telopeptide of type 1 collagen (CTX-1) was observed in response to cycling (ES0.5 0.65, 95% CrI 0.20-0.99), with greater durations and more work leading to larger CTX-1 increases. CTX-1 response peaked within 15 min and 2 h after the exercise bout. Other exercise types did not influence CTX-1. Changes to all bone formation markers were very small and transient, with the very small increases returning to baseline within 15 min of exercise cessation. No major trends for bone formation markers were identified across any of the moderating categories investigated. Certainty of evidence in most outcomes was deemed to be low or very low. CONCLUSION: The large influence of an acute bout of prolonged cycling on the bone resorption marker CTX-1, alongside the lack of a response of any biomarker to resistance or high-impact exercise types, indicate that these biomarkers may be more useful at investigating potentially osteolytic aspects of exercise, and raises questions about their suitability to investigate the osteogenic potential of different exercise types, at least in the short term and in response to a single exercise bout. Certainty in all outcomes was low or very low, due to factors including risk of bias, lack of non-exercise controls, inconsistency, imprecision and small-study effects. PROTOCOL REGISTRATION AND PUBLICATION: This investigation was prospectively registered on the Open Science Framework Registry ( https://osf.io/6f8dz ) and the full protocol underwent peer review prior to conducting the investigation.
Authors: Wendy M Kohrt; Sarah J Wherry; Pamela Wolfe; Vanessa D Sherk; Toby Wellington; Christine M Swanson; Connie M Weaver; Rebecca S Boxer Journal: J Bone Miner Res Date: 2018-04-18 Impact factor: 6.741
Authors: Hyunil Ha; Han Bok Kwak; Soo Woong Lee; Hye Mi Jin; Hyun-Man Kim; Hong-Hee Kim; Zang Hee Lee Journal: Exp Cell Res Date: 2004-12-10 Impact factor: 3.905