Ongphiphadhanakul B, Rajatanavin R, Chailurkit L, Piaseu N, Teerarungsikul K, Sirisriro R, Komindr S, Puavilai G
Department of Medicine, Mahidol University, Bangkok, Thailand.
Clin Endocrinol (Oxf). 1995 Dec;43(6):727-33. doi: 10.1111/j.1365-2265.1995.tb00542.x.
Bone mineral density (BMD) declines with age in both men and women, predisposing the elderly to osteoporosis and fractures. Although there are extensive data about post-menopausal osteoporosis, there is relatively little information concerning the decrease in BMD with age in normal men, particularly the contribution of declining gonadal function with age to BMD. In the present study, we investigated the effect of age on the pituitary-gonadal axis in normal males and its relation to BMD and body composition.
Ninety healthy Thai males in the Bangkok Metropolitan area without a history of smoking or significant alcohol consumption were studied.
Serum testosterone (T), free testosterone (FT), LH and FSH were measured by radioimmunoassay in fasting blood samples obtained in the morning between 0600 and 1000 h. BMD at anteroposterior L2-L4, lateral L2-L4, femoral neck, femoral trochanter and Ward's triangle were determined by dual-energy X-ray absorptiometry.
There were significant declines with age in BMD at lateral L2-L4 (r = -0.37, P < 0.001), femoral neck (r = -0.49, P < 0.0001), Ward's triangle (r = -0.54, P < 0.0001) but not at anteroposterior L2-L4 or femoral trochanter. Serum FT (r = -0.56, P < 0.0001) but not T (r = -0.19, P = 0.07) decreased with age. Serum LH (r = 0.27, P < 0.001) and FSH (r = 0.4, P < 0.0001) increased with age suggesting a defect in gonadal androgen synthesis or possibly a secretion of bioinactive LH. Serum FT concentrations were significantly correlated to lateral L2-L4 (r = 0.27, P < 0.05), femoral neck (r = 0.48, P < 0.0001) and Ward's triangle (r = 0.50, P < 0.0001) BMD. After controlling for age, declining FT with age was still associated with a decrease in BMD in femoral neck (P < 0.05) and Ward's triangle (P < 0.05) but not in lateral L2-L4. The proportion of body fat increased with age (r = 0.3, P < 0.01). Decreased serum T, but not FT, was associated with increased body fat after age was taken into account (P < 0.0001).
There is a decline in serum free testosterone together with increases in LH and FSH with age in healthy males. The decrease in serum free testosterone is partially associated with the age-related decline in bone mineral density added to the effect of age at the femoral neck and Ward's triangle. Testosterone but not free testosterone is associated with age-related increase in body fat.
男性和女性的骨矿物质密度（BMD）均会随年龄增长而下降，这使老年人易患骨质疏松症和骨折。尽管有大量关于绝经后骨质疏松症的数据，但关于正常男性BMD随年龄下降的信息相对较少，尤其是性腺功能随年龄下降对BMD的影响。在本研究中，我们调查了年龄对正常男性垂体-性腺轴的影响及其与BMD和身体成分的关系。
对曼谷都会区90名无吸烟史或大量饮酒史的健康泰国男性进行了研究。
于上午6点至10点采集空腹血样，采用放射免疫分析法测定血清睾酮（T）、游离睾酮（FT）、促黄体生成素（LH）和促卵泡生成素（FSH）。采用双能X线吸收法测定腰椎2-4前后位、腰椎2-4侧位、股骨颈、股骨粗隆和Ward三角区的BMD。
腰椎2-4侧位（r = -0.37，P < 0.001）、股骨颈（r = -0.49，P < 0.0001）、Ward三角区（r = -0.54，P < 0.0001）的BMD随年龄增长显著下降，但腰椎2-4前后位和股骨粗隆的BMD无明显下降。血清FT随年龄增长而下降（r = -0.56，P < 0.0001），而血清T无明显下降（r = -0.19，P = 0.07）。血清LH（r = 0.27，P < 0.001）和FSH（r = 0.4，P < 0.0001）随年龄增长而升高，提示性腺雄激素合成存在缺陷或可能存在生物活性LH分泌异常。血清FT浓度与腰椎2-4侧位（r = 0.27，P < 0.05）、股骨颈（r = 0.48，P < 0.0001）和Ward三角区（r = 0.50，P < 0.0001）的BMD显著相关。在控制年龄因素后，随年龄增长FT下降仍与股骨颈（P < 0.05）和Ward三角区（P < 0.05）的BMD下降相关，但与腰椎2-4侧位无关。身体脂肪比例随年龄增长而增加（r = 0.3，P < 0.01）。在考虑年龄因素后，血清T下降而非FT下降与身体脂肪增加相关（P < 0.0001）。
健康男性血清游离睾酮随年龄增长而下降，同时LH和FSH升高。血清游离睾酮下降部分与年龄相关的骨矿物质密度下降有关，此外还与股骨颈和Ward三角区的年龄效应有关。睾酮而非游离睾酮与年龄相关的身体脂肪增加有关。
