Division of Endocrinology and Metabolism, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
JACC Cardiovasc Imaging. 2013 Jul;6(7):762-71. doi: 10.1016/j.jcmg.2012.11.021. Epub 2013 May 8.
The aim of this study was to evaluate whether computed tomography (CT) attenuation, as a measure of fat quality, is associated with cardiometabolic risk factors above and beyond fat quantity.
Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) are pathogenic fat depots associated with cardiometabolic risk. Adipose tissue attenuation in CT images is variable, similar to adipose tissue volume. However, whether the quality of abdominal fat attenuation is associated with cardiometabolic risk independent of the quantity is uncertain.
Participants were drawn from the Framingham Heart Study CT substudy. The VAT and SAT volumes were acquired by semiquantitative assessment. Fat quality was measured by CT attenuation and recorded as mean Hounsfield unit (HU) within each fat depot. Sex-specific linear and logistic multivariable regression models were used to assess the association between standard deviation (SD) decrease in HU and each risk factor.
Lower CT attenuation of VAT and SAT was correlated with higher body mass index levels in both sexes. Risk factors were generally more adverse with decreasing HU values. For example, in women, per 1 SD decrease in VAT HU, the odds ratio (OR) was increased for hypertension (OR: 1.80), impaired fasting glucose (OR: 2.10), metabolic syndrome (OR: 3.65), and insulin resistance (OR: 3.36; all p < 0.0001). In models that further adjusted for VAT volume, impaired fasting glucose, metabolic syndrome, and insulin resistance remained significant. Trends were similar but less pronounced for SAT and for men. There was evidence of an interaction between HU and fat volume among both women and men.
Lower CT attenuation of VAT and SAT is associated with adverse cardiometabolic risk above and beyond total adipose tissue volume. Qualitative indices of abdominal fat depots may provide insight regarding cardiometabolic risk independent of fat quantity.
本研究旨在评估 CT 衰减（作为脂肪质量的衡量标准）是否与心血管代谢危险因素相关，且这种相关性是否独立于脂肪量。
内脏脂肪组织（VAT）和皮下脂肪组织（SAT）是与心血管代谢风险相关的致病性脂肪沉积。CT 图像中脂肪衰减的变化与脂肪体积相似。然而，腹部脂肪衰减的质量是否与心血管代谢风险相关，而与脂肪量无关，目前尚不确定。
参与者来自弗雷明汉心脏研究 CT 子研究。通过半定量评估获得 VAT 和 SAT 体积。通过 CT 衰减测量脂肪质量，并记录每个脂肪沉积处的平均 Hounsfield 单位（HU）。采用性别特异性线性和逻辑多变量回归模型评估 HU 标准差降低与每个风险因素之间的关系。
在男性和女性中，VAT 和 SAT 的 CT 衰减值越低，体质量指数水平越高。一般来说，随着 HU 值的降低，风险因素更为不利。例如，在女性中，VAT HU 每降低 1 个标准差，高血压的比值比（OR）增加（OR：1.80），空腹血糖受损（OR：2.10），代谢综合征（OR：3.65）和胰岛素抵抗（OR：3.36；均 p < 0.0001）。在进一步调整 VAT 体积的模型中，空腹血糖受损、代谢综合征和胰岛素抵抗仍然显著。对于 SAT 和男性，趋势相似但程度较轻。在女性和男性中，均存在 HU 与脂肪量之间相互作用的证据。
VAT 和 SAT 的 CT 衰减值越低，与心血管代谢危险因素的相关性越显著，且这种相关性独立于脂肪总量。腹部脂肪沉积的定性指标可能为心血管代谢风险提供独立于脂肪量的见解。
