Baumgartner R N, Ross R R, Waters D L, Brooks W M, Morley J E, Montoya G D, Garry P J
Center for Population Health, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque 87131, USA.
Obes Res. 1999 Mar;7(2):141-9. doi: 10.1002/j.1550-8528.1999.tb00695.x.
There are few data for associations of serum leptin with body fat, fat distribution, sex hormones, or fasting insulin in elderly adults. We hypothesized that the sex difference in serum leptin concentrations would disappear after adjustment for subcutaneous, but not visceral body fat. Serum leptin would not be associated with sex hormone concentrations or serum fasting insulin after adjusting for body fat and fat distribution.
Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) volumes were measured using magnetic resonance imaging in a cross-sectional sample of 56 nondiabetic, elderly men and women aged 64 years to 94 years. Serum leptin, sex hormones (testosterone and estrone), sex hormone-binding globulin, and fasting insulin were also measured. Nine women were taking hormone replacement, and five men were clinically hypogonadal.
Leptin was significantly associated with both SAT and VAT in each sex. Adjustment for SAT reduced the sex difference in leptin by 56%, but adjustment for VAT increased the difference by 25%. Leptin was not associated with serum estrone or hormone replacement therapy in the women, but had a significant, negative association with testosterone in the men that was independent of SAT, but not VAT. Leptin was significantly associated with fasting insulin in both sexes independent of age, sex hormones, sex hormone-binding globulin, VAT and SAT.
Sex difference in serum leptin is partly explained by different amounts of SAT. Studies including both men and women should adjust for SAT rather than total body fat that includes VAT. The sex difference in serum leptin is not due to estrogen, but may be partly explained by testosterone. Testosterone is negatively associated with leptin in men, but the association is confounded with VAT. Leptin is associated with fasting insulin in nondiabetic elderly men and women independent of body fat, fat distribution, or sex hormones.
关于老年成年人血清瘦素与体脂、脂肪分布、性激素或空腹胰岛素之间关联的数据较少。我们假设，在调整皮下脂肪而非内脏脂肪后，血清瘦素浓度的性别差异将会消失。在调整体脂和脂肪分布后，血清瘦素将与性激素浓度或血清空腹胰岛素无关。
采用磁共振成像技术，对56名年龄在64岁至94岁之间的非糖尿病老年男性和女性的横断面样本测量皮下脂肪组织（SAT）和内脏脂肪组织（VAT）体积。同时测量血清瘦素、性激素（睾酮和雌酮）、性激素结合球蛋白和空腹胰岛素。9名女性正在接受激素替代治疗，5名男性存在临床性腺功能减退。
在男女两性中，瘦素均与SAT和VAT显著相关。调整SAT后，瘦素的性别差异降低了56%，但调整VAT后，差异增加了25%。在女性中，瘦素与血清雌酮或激素替代治疗无关，但在男性中，瘦素与睾酮存在显著的负相关，该相关性独立于SAT，但不独立于VAT。无论年龄、性激素、性激素结合球蛋白、VAT和SAT如何，瘦素在男女两性中均与空腹胰岛素显著相关。
血清瘦素的性别差异部分可由不同量的SAT来解释。纳入男性和女性的研究应调整SAT而非包括VAT的总体脂。血清瘦素的性别差异并非由雌激素引起，但可能部分由睾酮来解释。睾酮在男性中与瘦素呈负相关，但该相关性与VAT存在混杂。在非糖尿病老年男性和女性中，瘦素与空腹胰岛素相关，且独立于体脂、脂肪分布或性激素。
