Roy Tracey Ann, Blackman Marc R, Harman S Mitchell, Tobin Jordan D, Schrager Matthew, Metter E Jeffery
Laboratory of Clinical Investigation, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA>.
Am J Physiol Endocrinol Metab. 2002 Aug;283(2):E284-94. doi: 10.1152/ajpendo.00334.2001.
Muscle mass and strength losses during aging may be associated with declining levels of serum testosterone (T) in men. Few studies have shown a direct relationship between T and muscle mass and strength. Subjects were 262 men, aged 24-90 yr, from the Baltimore Longitudinal Study of Aging, who had T and sex hormone-binding globulin sex hormone-binding globulin (SHBG) measurements, from which the free T index (FTI) was calculated (T/SHBG) from serum samples collected longitudinally since 1963, total body fat mass and arm and leg fat-free mass (FFM) by dual-energy X-ray absorptiometry and arm and leg strength by dynanomometry. Mixed-effects models estimated T and FTI at the time of mass and strength measurements. Age, total body fat, arm and leg FFM, T, and FTI were significantly associated with concentric and eccentric strength. FTI, not T, was modestly, but directly, related to arm and leg strength after fat, arm and leg FFM, height, and age were accounted for and indirectly through body mass. FTI is a better predictor of arm and leg strength than T in aging men.
衰老过程中肌肉量和力量的丧失可能与男性血清睾酮（T）水平下降有关。很少有研究表明睾酮与肌肉量和力量之间存在直接关系。研究对象为来自巴尔的摩衰老纵向研究的262名年龄在24 - 90岁之间的男性，他们进行了睾酮和性激素结合球蛋白（SHBG）的测量，并根据1963年以来纵向采集的血清样本计算游离睾酮指数（FTI）（T/SHBG），通过双能X线吸收法测量全身脂肪量以及手臂和腿部的去脂体重（FFM），并通过测力计测量手臂和腿部力量。混合效应模型估计了在测量肌肉量和力量时的睾酮和游离睾酮指数。年龄、全身脂肪、手臂和腿部去脂体重、睾酮和游离睾酮指数与向心和离心力量显著相关。在考虑脂肪、手臂和腿部去脂体重、身高和年龄因素后，游离睾酮指数而非睾酮与手臂和腿部力量存在适度但直接的关系，并且通过体重间接相关。在衰老男性中，游离睾酮指数比睾酮更能预测手臂和腿部力量。
