Mohr Beth A, Bhasin Shalender, Link Carol L, O'Donnell Amy B, McKinlay John B
New England Research Institutes, 9 Galen Street, Watertown, Massachusetts 02472, USA.
Eur J Endocrinol. 2006 Sep;155(3):443-52. doi: 10.1530/eje.1.02241.
Changes in adiposity affecting total testosterone (TT) and free testosterone (FT) levels have not been examined in a population-based survey. We aimed to determine whether changes in adiposity predict follow-up levels and rates of change in TT, FT and sex hormone-binding globulin (SHBG) in men.
The Massachusetts Male Aging Study is a randomly sampled, population-based cohort interviewed at baseline (T(1), 1987-1989; n = 1,709; aged 40-70 years) and followed-up approximately 9 years later (T(2), 1995-1997; n = 1,156). Men were categorized as overweight (body mass index (BMI) >or= 25 kg/m(2)) or having obesity (BMI >or= 30 kg/m(2)), waist obesity (waist circumference >or= 102 cm), or waist-to-hip ratio (WHR) obesity (WHR>0.95). For each adiposity group, we constructed four categories to represent changes between T(1) and T(2): overweight (or obese, etc.) at neither wave, T(1) only, T(2) only, or both waves.
After adjustment for confounding variables, men who were overweight at T(2) only, or at both waves, had significantly lower mean T(2) TT and SHBG levels than men in the neither group (P<0.05). Mean FT did not differ between any overweight group and the neither group. Men who were obese at both times, had the highest mean BMI, the highest fraction of severely obese men, and significantly greater rate of decline in FT than the neither group.
In men who become overweight, the greater rate of decline in TT, but not FT, is related mostly to a lesser age-related increase in SHBG. Since weight gain is highly prevalent in older men, over-reliance on TT levels in the diagnosis of androgen deficiency could result in substantial misclassification.
在一项基于人群的调查中，尚未对影响总睾酮（TT）和游离睾酮（FT）水平的肥胖变化进行研究。我们旨在确定肥胖变化是否能预测男性随访时TT、FT和性激素结合球蛋白（SHBG）的水平及变化率。
马萨诸塞州男性衰老研究是一项基于人群的随机抽样队列研究，在基线时（T(1)，1987 - 1989年；n = 1709；年龄40 - 70岁）进行访谈，并在约9年后进行随访（T(2)，1995 - 1997年；n = 1156）。男性被分为超重（体重指数（BMI）≥25 kg/m²）或肥胖（BMI≥30 kg/m²）、腹型肥胖（腰围≥102 cm）或腰臀比（WHR）肥胖（WHR>0.95）。对于每个肥胖组，我们构建了四类来表示T(1)和T(2)之间的变化：两阶段均不超重（或肥胖等）、仅T(1)超重、仅T(2)超重或两阶段均超重。
在对混杂变量进行调整后，仅在T(2)超重或两阶段均超重的男性，其T(2)时的平均TT和SHBG水平显著低于两阶段均不超重的男性（P<0.05）。任何超重组与两阶段均不超重组之间的平均FT无差异。两阶段均肥胖的男性平均BMI最高，重度肥胖男性比例最高，且FT下降率显著高于两阶段均不超重的男性。
在超重的男性中，TT下降率较高，但FT并非如此，这主要与SHBG随年龄增长的增加幅度较小有关。由于体重增加在老年男性中非常普遍，在雄激素缺乏诊断中过度依赖TT水平可能会导致大量误诊。
