Journal of Bone and Mineral Metabolism

, Volume 30, Issue 5, pp 534–542

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

  • Eimear Dolan
  • Adrian McGoldrick
  • Colin Davenport
  • Grainne Kelleher
  • Brendan Byrne
  • William Tormey
  • Diarmuid Smith
  • Giles D. Warrington
Original article

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.

Keywords

Jockeys Energy restriction Bone Testosterone 

References

  1. 1.
    Dolan E, O’Connor H, O’Loughlin G, McGoldrick A, Warrington G (2011) Nutritional, lifestyle and weight-control practices of professional jockeys. J Sports Sci 29:791–799PubMedCrossRefGoogle Scholar
  2. 2.
    Moore JM, Timperio AF, Crawford DA, Cameron-Smith D (2002) Weight management and weight loss strategies of professional jockeys. Int J Sport Nutr Exerc Metab 12:1–13PubMedGoogle Scholar
  3. 3.
    Leydon MA, Wall C (2002) New Zealand jockeys’ dietary habits and their potential impact on health. Int J Sport Nutr Exerc 12:220–237Google Scholar
  4. 4.
    Warrington GD, Dolan E, McGoldrick A, McEvoy J, MacManus C, Griffin M, Lyons D (2009) Chronic weight control impacts on physiological function and bone health in elite jockeys. J Sports Sci 27:543–550PubMedCrossRefGoogle Scholar
  5. 5.
    Dolan E, Crabtree N, McGoldrick A, Ashley DT, McCaffrey N, Warrington GD (2011) Weight regulation and bone mass: a comparison between professional jockeys, elite amateur boxers and age. gender and bmi matched controls. J Bone Miner Metab. doi:10.1007/s00774-001-0297-1 PubMedGoogle Scholar
  6. 6.
    Frost HM (2003) Bone’s Mechanostat: A 2003 Update. Anat Rec Part A 275:1081–1101CrossRefGoogle Scholar
  7. 7.
    Cure–Cure C, Capozza RF, Cointry GR, Meta M, Cure-Ramirez P, Ferretti JL (2005) Reference chart for the relationships between dual energy X-ray absorptiometry assessed bone mineral content and lean mass in 3,063 healthy men and premenopausal and postmenopausal women. Osteoporos Int 16:2095–2106PubMedCrossRefGoogle Scholar
  8. 8.
    De Souza MJ, Williams NI (2004) Physiological aspects and clinical sequelae of energy deficiency and hypoestrogenism in exercising women. Human Reprod Update 10:433–448CrossRefGoogle Scholar
  9. 9.
    Loucks AB, Thuma JR (2003) Luteinizing hormone pulsatility is disrupted at a threshold of energy availability in regularly menstruating women. J Clin Endocrinol Metab 88:297–311PubMedCrossRefGoogle Scholar
  10. 10.
    Haspolat K, Ece A, Gurkan F, Atamer Y, Tutanc M, Yolbas I (2007) Relationship between leptin, insulin, IGF-1 and IGFBP3 in children with energy malnutrition. Clin Biochem 40:201–205PubMedCrossRefGoogle Scholar
  11. 11.
    Misra M, Miller KK, Bjornsen J, Hackman A, Aggarwal A, Chung J, Ott M, Herzog DB, Johnson ML, Klibanski A (2003) Alterations in growth hormone secretory dynamics in adolescent girls with anorexia nervosa and effects on bone metabolism. J Clin Endocrinol 88:5615–5623CrossRefGoogle Scholar
  12. 12.
    Solomon AM, Bouloux PMG (2006) Modifying muscle mass: the endocrine perspective. J Endocrinol 191:349–360PubMedCrossRefGoogle Scholar
  13. 13.
    Proteau S, Pelle A, Collomp K, Benhamou L, Courteix D (2006) Bone density in elite judoists and effects of weight cycling on bone metabolic balance. Med Sci Sports Exerc 38:694–700CrossRefGoogle Scholar
  14. 14.
    Vermeulen A, Verdonck L, Kaufman JM (1999) A critical evaluation of simple methods for the estimation of free testosterone in serum. J Clin Endocrinol Metab 84:3666–3672PubMedCrossRefGoogle Scholar
  15. 15.
    Boot AM, de Ridder MAJ, van der Sluis IM, van Slobbe I, Krenning EP, de Muinick Keizer-Schrama SMBF (2009) Peak bone mineral density, lean body mass and fractures. Bone 46:336–341PubMedCrossRefGoogle Scholar
  16. 16.
    Kroger H, Kotaniemi A, Vainio P, Alhava E (1992) Bone densitometry of the spine and femur in children by dual energy X-ray absorptiometry. Bone Miner Bone Mineral 17:75–85CrossRefGoogle Scholar
  17. 17.
    Molgaard C, Thomsen BL, Prentice A, Cole TJ, Michaelsen KF (1997) Whole body bone mineral density in healthy children and adolescents. Arch Dis 76:9–15CrossRefGoogle Scholar
  18. 18.
    Prentice A, Parsons TJ, Cole TJ (1994) Uncritical use of bone mineral density in absorptiometry may lead to size-related artifacts in the identification of bone mineral determinants. Am J Clin Nutr 60:837–842PubMedGoogle Scholar
  19. 19.
    Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM, Endocrine Society (2011) Evaluation, treatment and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 96:1911–1930PubMedCrossRefGoogle Scholar
  20. 20.
    Waller AE, Daniels JL, Weaver NL, Robinson P (2000) Jockey injuries in the United States. J Am Med Assoc 283:1326–1328CrossRefGoogle Scholar
  21. 21.
    Bass SL, Eser P, Daly R (2005) The effect of exercise and nutrition on the mechanostat. J Musculoskelet Neuronal Interact 5:239–254PubMedGoogle Scholar
  22. 22.
    Ferry B, Duclos M, Burt L, Therre P, LeGall F, Jaffre C, Courteix C (2011) Bone geometry and strength adaptations to physical constraints inherent in different sports: comparison between elite female soccer players and swimmers. J Bone Miner Metab 29:342–351PubMedCrossRefGoogle Scholar
  23. 23.
    Garnero P, Sornay-Rendu E, Claustrat B, Delmas PD (2000) Biochemical markers of bone turnover, endogenous hormones and the risk of fractures in postmenopausal women: the OFELY study. J Bone Miner Res 15:1526–1536PubMedCrossRefGoogle Scholar
  24. 24.
    Mora S, Gilsanz V (2003) Establishment of peak bone mass. Endocrinol Metab Clin North Am 32:39–63PubMedCrossRefGoogle Scholar
  25. 25.
    Hansen MA, Overgaard K, Riis BJ, Christiansen C (1991) Role of peak bone mass and bone loss in postmenopausal osteoporosis: 12 year study. BMJ 303:961–964PubMedCrossRefGoogle Scholar
  26. 26.
    Waldron-Lynch F, Murray BF, Brady JJ, McKenna MJ, McGoldrick A, Warrington G, O’Loughlin G, Barragry JM (2009) High bone turnover in irish professional jockeys. Osteoporos Int 21:521–525PubMedCrossRefGoogle Scholar
  27. 27.
    Iuliano Burns S, Wang XF, Ayton J, Jones G (2009) Skeletal and hormonal responses to sunlight deprivation in Antarctic expeditioners. Osteoporos Int 20:1523–1528PubMedCrossRefGoogle Scholar
  28. 28.
    Ihle R, Loucks AB (2004) Dose response relationships between energy availability and bone turnover in young exercising women. J Bone Miner Res 19:1231–1240PubMedCrossRefGoogle Scholar
  29. 29.
    Kahn SM, Hryb DJ, Nakhla AM, Romas NA (2002) Sex hormone binding globulin is synthesized in target cells. J Endocrinol 175:113–120PubMedCrossRefGoogle Scholar
  30. 30.
    Khosla S, Melton LJ, Atkinson EJ, O’Fallon WM, Klee GG, Riggs BL (1998) Relationship of serum sex steroid levels and bone turnover markers with bone mineral density in men and women: a key role for bioavailable estrogen. J Clin Endocrinol Metab 83:2266–2274PubMedCrossRefGoogle Scholar
  31. 31.
    Frystyk J, Delhanty PJD, Skjerbek C, Baxter RC (1999) Changes in the circulating IGF system during short term fasting and refeeding. Am J Physiol Endocrinol Metab 40:245–252Google Scholar
  32. 32.
    Rajaram S, Baylink DJ, Mohan S (1997) Insulin like growth factor binding proteins in serum and other biological fluids: regulation and functions. Endocr Rev 18:801–831PubMedCrossRefGoogle Scholar
  33. 33.
    Aimaretti G, Corneli G, Di Somma C, Baldilli R, Gasco V, Rovere S, Migliaretti G, Colao A, Tamburrano G, Lombardi G, Chigo E, Camami F (2005) Different degrees of gh deficiency evidenced by GHRH + arginine test and IGF-1 levels in adults with pituitary disease. J Endocrinolol Invest 28:247–252Google Scholar
  34. 34.
    Holt RIG, Webb E, Pentecost C, Sonksen PH (2001) Aging and physical fitness are more important than obesity in determining exercise-induced generation of GH. J Clin Endocrinol Metab 86:5715–5720PubMedCrossRefGoogle Scholar
  35. 35.
    Nindl BC, Pierce JR, Durkot MJ, Tuckow AP, Kennett MJ, Nieves JW, Cosman F, Alemany JA, Hymer WC (2008) Relationship between growth hormone in vivo bioactivity, the insulin like growth factor 1 system and bone mineral density in young, physically fit men and women. Growth Horm IGF Res 18:439–445PubMedCrossRefGoogle Scholar
  36. 36.
    Rubin J, Ackert-Bicknell CL, Zhu L, Fan X, Murphy TC, Nanes MS, Marcus R, Holloway L, Beamer WG, Rosen CJ (2002) IGF-1 regulates osteoprotegerin (OPG) and receptor activator of nuclear factor-kB ligand in vitro and OPG in vivo. J Clin Endocrinol Metab 87:4273–4279PubMedCrossRefGoogle Scholar
  37. 37.
    Ueland T (2004) Bone metabolism in relation to alterations in systemic growth hormone. Growth Horm IGF Res 14:404–417PubMedCrossRefGoogle Scholar
  38. 38.
    Garnero P, Sornay E, Rendu E, Delmas PD (2000) Low serum IGF-1 and recurrence of osteoporotic fractures in postmenopausal women. Lancet 355:898–899PubMedCrossRefGoogle Scholar
  39. 39.
    Sjogren KS, Sheng M, Moverare S, Liu JL, Wallenius K, Tornell J, Isaksson O, Jansson J, Mohan S, Ohlsson C (2002) Effects of liver derived insulin-like growth factor 1 on bone metabolism in mice. J Bone Miner Res 17:342–351CrossRefGoogle Scholar
  40. 40.
    Nattiv A, Loucks AB, Manore MM, Sunborn CF, Sundgot-Borgen J, Warren MP (2007) The female athlete triad: ACSM position stand. Med Sci Sports Exerc 39:1867–1882PubMedCrossRefGoogle Scholar

Copyright information

© The Japanese Society for Bone and Mineral Research and Springer 2012

Authors and Affiliations

  • Eimear Dolan
    • 1
  • Adrian McGoldrick
    • 2
  • Colin Davenport
    • 3
  • Grainne Kelleher
    • 3
  • Brendan Byrne
    • 3
  • William Tormey
    • 3
  • Diarmuid Smith
    • 3
  • Giles D. Warrington
    • 4
  1. 1.School of Health SciencesRobert Gordon UniversityAberdeenScotland, UK
  2. 2.The Turf ClubKildareIreland
  3. 3.Academic Department of EndocrinologyBeaumont Hospital, The Royal College of SurgeonsDublinIreland
  4. 4.School of Health and Human PerformanceDublin City UniversityDublinIreland

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