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Home / Equine Research Bank / J Bone Miner Metab / An altered hormonal profile and elevated rate of bone loss a...
Journal of bone and mineral metabolism2012; 30(5); 534-542; doi: 10.1007/s00774-012-0354-4

An altered hormonal profile and elevated rate of bone loss are associated with low bone mass in professional horse-racing jockeys.

Abstract: Horse-racing jockeys are a group of weight-restricted athletes, who have been suggested as undertaking rapid and extreme weight cycling practices in order to comply with stipulated body-mass standards. The aim of this study was to examine bone mass, turnover and endocrine function in jockeys and to compare this group with age, gender and body mass index matched controls. Twenty male professional jockeys and 20 healthy male controls participated. Dual energy X-ray absorptiometry scans and early morning fasting blood and urine samples were used to measure bone mass, turnover and a hormonal profile. Total body bone mineral density (BMD) was significantly lower in jockeys (1.143 ± 0.05 vs. 1.27 ± 0.06 g cm(-3), p < 0.01). Bone resorptive activity was elevated in the jockey group as indicated by significantly higher urinary NTx/creatinine (76.94 ± 29.52 vs. 55.9 ± 13.9 nmol mmol(-1), p < 0.01), resulting in a significantly negative uncoupling index between bone resorption and formation. Sex hormone binding globulin (SHBG) levels were significantly higher in jockeys (41.21 ± 9.77 vs. 28.24 ± 9.98 nmol L(-1), p < 0.01) with a lower percentage of bioavailable testosterone (48.89 ± 7.38 vs. 59.18 ± 6.74 %, p < 0.01). SHBG and insulin-like growth factor-1 were independent predictors of total body and femoral neck BMD, respectively (p < 0.05). In conclusion, it appears that professional jockeys have an elevated rate of bone loss and reduced bone mass that appears to be associated with disrupted hormonal activity. It is likely that this may have occurred in response to the chronic weight cycling habitually experienced by this group.
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Publication Date: 2012-04-11 PubMed ID: 22491874DOI: 10.1007/s00774-012-0354-4Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This study found that professional jockeys, due to weight restrictions and weight cycling practices, have an increased rate of bone loss and lower bone mass, likely due to disrupted hormonal activity.

Objective of the Study

  • The goal of the research was to examine bone mass, bone turnover, and endocrine function in professional jockeys and compare this group to controls of the same age, gender, and body mass index. The hypothesis was that extreme weight cycling practices might lead to unhealthy bone and hormonal conditions in jockeys due to the pressure to maintain low body weight for their profession.

Study Design and Participants

  • The study involved twenty male professional jockeys and twenty healthy male controls.
  • To measure bone mass, turnover rate, and hormones, they used Dual energy X-ray absorptiometry scans and early morning fasting blood and urine samples.

Key Findings

  • Jockeys had significantly lower body bone mineral density (BMD) compared to the control group.
  • Bone resorptive activity, or bone loss, was significantly higher in the jockey group, leading to a negative uncoupling index between bone resorption and formation—a sign of increased bone loss.
  • Jockeys had significantly higher levels of sex hormone binding globulin (SHBG)—a protein that binds to sex hormones, reducing their bioavailability. This resulted in a lower percentage of available testosterone in jockeys.
  • SHBG and insulin-like growth factor-1 were also found to predict total body and femoral neck BMD, respectively, implying their potential role in the disrupted bone health in jockeys.

Conclusion

  • The study concludes that professional jockeys have an elevated rate of bone loss and reduced bone mass, likely happening due to disrupted hormonal activity.
  • This is hypothesized to be a response to the chronic weight cycling habitually experienced by this group due to their professional requirements.

Cite This Article

APA
Dolan E, McGoldrick A, Davenport C, Kelleher G, Byrne B, Tormey W, Smith D, Warrington GD. (2012). An altered hormonal profile and elevated rate of bone loss are associated with low bone mass in professional horse-racing jockeys. J Bone Miner Metab, 30(5), 534-542. https://doi.org/10.1007/s00774-012-0354-4

Publication

Journal of bone and mineral metabolism
ISSN: 1435-5604
NlmUniqueID: 9436705
Country: Japan
Language: English
Volume: 30
Issue: 5
Pages: 534-542

Researcher Affiliations

Dolan, Eimear
  • School of Health Sciences, Robert Gordon University, Garthdee Road, Aberdeen, AB10 7QG, Scotland, UK. e.dolan@rgu.ac.uk
McGoldrick, Adrian
    Davenport, Colin
      Kelleher, Grainne
        Byrne, Brendan
          Tormey, William
            Smith, Diarmuid
              Warrington, Giles D

                MeSH Terms

                • Absorptiometry, Photon / methods
                • Adult
                • Animals
                • Athletes
                • Body Composition / physiology
                • Body Mass Index
                • Bone Density / physiology
                • Bone Resorption / blood
                • Bone Resorption / metabolism
                • Bone Resorption / pathology
                • Bone Resorption / urine
                • Creatinine / urine
                • Femur Neck / metabolism
                • Femur Neck / pathology
                • Hormones / metabolism
                • Horses
                • Humans
                • Insulin-Like Growth Factor I / metabolism
                • Male
                • Osteogenesis / physiology
                • Sex Hormone-Binding Globulin / metabolism
                • Sports
                • Testosterone / blood
                • Young Adult

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                This article has been cited 16 times.
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