School of Health Sciences, Robert Gordon University, Garthdee Road, Aberdeen, AB10 7QG, Scotland, UK.
J Bone Miner Metab. 2012 Sep;30(5):534-42. doi: 10.1007/s00774-012-0354-4. Epub 2012 Apr 11.
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.
赛马骑师是一群体重受限的运动员，他们被认为采取了快速和极端的体重循环训练，以符合规定的体重标准。本研究的目的是检查骑师的骨量、骨转换和内分泌功能，并将该组与年龄、性别和体重指数匹配的对照组进行比较。20 名男性职业骑师和 20 名健康男性对照者参与了研究。双能 X 线吸收法（DXA）扫描和清晨空腹血液及尿液样本用于测量骨量、骨转换和激素谱。骑师组的全身骨矿物质密度（BMD）明显较低（1.143±0.05 对 1.27±0.06 g·cm(-3)，p<0.01）。骑师组的骨吸收活性升高，表现为尿 NTx/creatinine 显著升高（76.94±29.52 对 55.9±13.9 nmol·mmol(-1)，p<0.01），导致骨吸收和形成之间的解偶联指数显著为负。骑师组的性激素结合球蛋白（SHBG）水平明显升高（41.21±9.77 对 28.24±9.98 nmol·L(-1)，p<0.01），生物可利用睾酮的百分比降低（48.89±7.38 对 59.18±6.74%，p<0.01）。SHBG 和胰岛素样生长因子-1 分别是全身和股骨颈 BMD 的独立预测因子（p<0.05）。综上所述，职业骑师的骨丢失率较高，骨量减少，这似乎与激素活动紊乱有关。这可能是由于该人群经常经历慢性体重循环所致。
