Li J-Y, Li X-Y, Li M, Zhang G-K, Ma F-L, Liu Z-M, Zhang N-Y, Meng P
Department of Endocrinology, PLA General Hospital, Beijing, China.
Aging Male. 2005 Sep-Dec;8(3-4):203-6. doi: 10.1080/13685530500356010.
To investigate the age-related change of serum androgen levels in healthy men and to define a cut-off value of serum testosterone for the diagnosis of androgen deficiency in the aging male.
1080 healthy men aged 20 to 70 years old were enrolled in Beijing, Shanghai, Xian and Chongqing. Luteinizing hormone (LH), follicle-stimulating hormone (FSH), total testosterone (T), calculated free testosterone (cFT), sex hormone binding globulin (SHBG), 17beta-oestradiol (E2), the T/LH ratio, and T/SHBG as a free testosterone index (FTI) were all determined.
Serum total T did not significantly decline, but the cFT, T/LH and FTI progressively decreased with aging. To determine androgen deficiency, the 10th percentile value of men < 40 years was defined as the lower cut-off value for cFT, T/LH or FTI, which were 0.3 nmol/L, 2.8 nmol/IU, and 0.4 nmol/IU respectively. With the median value of cFT of men aged between 20 and 49 years as the criterion, the level of cFT was lower in 2.82% of men from 40 to 49 years, in 19.53% from 50 to 59 years, in 22.57% from 60 to 69 years, and in 33.19% of men > or = 70 years. Taking the above value of cFT as the cut-off point, the prevalence of androgen deficiency in men 40-49 years was 13.0%, 31.8% in men 50-59 years, 30.1% in men 60 to 69 years, and 46.7% in men > 70 years.
(i). While serum total T values do not decline with aging, the levels of cFT gradually decline with aging; (ii) when using the value of cFT of the 10th percentile of men aged 20 to 39 years as the cut-off point, the prevalence of androgen deficiency was < 15% before the age of 50 years, and about 30% thereafter, approaching 45% after the age of 70 years; and (iii) in this study the values of T/LH paralleled those of cFT closely; therefore, T/LH could serve as a surrogate for cFT.
研究健康男性血清雄激素水平随年龄的变化，并确定诊断老年男性雄激素缺乏的血清睾酮临界值。
在北京、上海、西安和重庆招募了1080名年龄在20至70岁之间的健康男性。测定了促黄体生成素（LH）、促卵泡生成素（FSH）、总睾酮（T）、计算游离睾酮（cFT）、性激素结合球蛋白（SHBG）、17β-雌二醇（E2）、T/LH比值以及作为游离睾酮指数（FTI）的T/SHBG。
血清总T没有显著下降，但cFT、T/LH和FTI随年龄增长逐渐降低。为确定雄激素缺乏，将年龄<40岁男性的第10百分位数定义为cFT、T/LH或FTI的下限临界值，分别为0.3 nmol/L、2.8 nmol/IU和0.4 nmol/IU。以20至49岁男性cFT的中位数为标准，40至49岁男性中2.82%的cFT水平较低，50至59岁男性中为19.53%，60至69岁男性中为22.57%，70岁及以上男性中为33.19%。以上述cFT值为临界点，40至49岁男性雄激素缺乏的患病率为13.0%，50至59岁男性中为31.8%，60至69岁男性中为30.1%，70岁以上男性中为46.7%。
（i）虽然血清总T值不随年龄下降，但cFT水平随年龄逐渐下降；（ii）以20至39岁男性第10百分位数的cFT值为临界点，50岁之前雄激素缺乏的患病率<15%，此后约为30%，70岁以后接近45%；（iii）在本研究中，T/LH值与cFT值密切平行；因此，T/LH可作为cFT的替代指标。
