Rudman D, Drinka P J, Wilson C R, Mattson D E, Scherman F, Cuisinier M C, Schultz S
Department of Medicine, Medical College of Wisconsin, Milwaukee 53295-1000.
Clin Endocrinol (Oxf). 1994 May;40(5):653-61. doi: 10.1111/j.1365-2265.1994.tb03018.x.
It has been proposed that declining activities of the somatotrophic or gonadotrophic axes, or sedentary life style, are partial causes for geriatric losses of bone mineral density (BMD) and of lean body mass (LBM). The present study tested these hypotheses by determining, in both free-living and institutionalized elderly men, the correlations of bone mineral density (BMD), total body bone mineral content (TBBMC) and lean body mass (LBM) with the following predictor variables: age, body mass index, body weight, serum insulin-like growth factor I (IGF-I), serum testosterone, habitual physical activity and mobility.
Forty-nine independent, community-dwelling older men, and 49 men of similar age residing in two Veterans Administration extended care facilities. The age range was 58-95 years.
Serum IGF-I and testosterone were measured by radioimmunoassay. Habitual physical activity in the independent men and mobility in the institutionalized men were estimated by standard instruments. LBM and bone status at nine skeletal sites were determined by dual X-ray absorptiometry.
The BMD and TBBMC values of the free living men were 4-20% higher than those of the institutionalized men. In the independent old men, serum testosterone was the strongest predictor of BMD and TBBMC, while age was the only predictor of LBM. In the chronically institutionalized men, age, body weight and immobility were the strongest predictors of body composition, and testosterone was correlated only with femoral neck BMD.
In aging independent men, low levels of testosterone are associated with demineralization of the skeleton. Immobility and under-weight are associated with the osteopenia of old men residing in nursing homes. In this cross-sectional study of elderly men, there was no evidence of a relation of the somatotrophic axis to bone status or LBM, or of the gonadotrophic axis to LBM.
有人提出，生长激素轴或促性腺激素轴活性下降，或久坐不动的生活方式，是老年人骨矿物质密度（BMD）和瘦体重（LBM）流失的部分原因。本研究通过在自由生活和机构养老的老年男性中，确定骨矿物质密度（BMD）、全身骨矿物质含量（TBBMC）和瘦体重（LBM）与以下预测变量之间的相关性，来检验这些假设：年龄、体重指数、体重、血清胰岛素样生长因子I（IGF-I）、血清睾酮、习惯性身体活动和活动能力。
49名独立居住在社区的老年男性，以及49名年龄相仿、居住在两个退伍军人管理局长期护理机构的男性。年龄范围为58 - 95岁。
采用放射免疫分析法测定血清IGF-I和睾酮。通过标准仪器评估独立生活男性的习惯性身体活动和机构养老男性的活动能力。采用双能X线吸收法测定九个骨骼部位的LBM和骨状态。
自由生活男性的BMD和TBBMC值比机构养老男性高4 - 20%。在独立生活的老年男性中，血清睾酮是BMD和TBBMC的最强预测因子，而年龄是LBM的唯一预测因子。在长期机构养老的男性中，年龄、体重和活动能力下降是身体成分的最强预测因子，睾酮仅与股骨颈BMD相关。
在衰老的独立生活男性中，低睾酮水平与骨骼脱矿有关。活动能力下降和体重不足与养老院老年男性的骨质减少有关。在这项老年男性的横断面研究中，没有证据表明生长激素轴与骨状态或LBM有关，也没有证据表明促性腺激素轴与LBM有关。
