DXA 校正的四肢瘦体重：老年人超声预测模型的建立。

DXA-Rectified Appendicular Lean Mass: Development of Ultrasound Prediction Models in Older Adults.

机构信息

Takashi Abe, 224 Turner Center, University, MS 38677, USA, Phone: +1 (662) 915-5567, FAX: +1 (662) 915-5525, Email:

出版信息

J Nutr Health Aging. 2018;22(9):1080-1085. doi: 10.1007/s12603-018-1053-1.

DOI:10.1007/s12603-018-1053-1

PMID:30379306

Abstract

OBJECTIVE

Dual-energy X-ray absorptiometry (DXA)-derived appendicular lean soft tissue mass (aLM) is used to diagnose sarcopenia. However, DXA-derived aLM includes non-skeletal muscle components, such as fat-free component of adipose tissue fat cell. These components, if not accounted for, could falsely inflate the aLM in individuals with a high amount of adipose tissue mass. B-mode ultrasound accurately measures muscle size in older adults. We sought to develop regression-based prediction equations for estimating DXA-rectified appendicular lean tissue mass (i.e. DXA-derived aLM minus appendicular fat-free adipose tissue (aFFAT); abbreviated as aLM minus aFFAT) using B-mode ultrasound.

DESIGN

Cross-sectional study.

MEASUREMENTS

Three hundred and eighty-nine Japanese older adults (aged 60 to 79 years) volunteered in the study. aLM was measured using a DXA, and muscle thickness (MT) was measured using ultrasound at nine sites. An ordinary least-squares multiple linear regression model was used to predict aLM minus aFFAT from sex, age and varying muscle thicknesses multiplied by height. Based on previous studies, we chose to use 4 MT sites at the upper and lower extremities (4-site MT model) and a single site (1-site MT model) at the upper extremity to develop prediction models.

RESULTS

The linear prediction models (4 site MT model; R2 = 0.902, adjusted R2 = 0.899, and 1-site MT model; R2 = 0.868, adjusted R2 = 0.866) were found to be stable and accurate for estimating aLM minus aFFAT. Bootstrapping (n=1000) resulted in optimism values of 0.0062 (4-site MT model) and 0.0036 (1-site MT model).

CONCLUSION

The results indicated that ultrasound MT combined with height, age and sex can be used to accurately estimate aLM minus aFFAT in older Japanese adults. Newly developed ultrasound prediction equations to estimate aLM minus aFFAT may be a valuable tool in population-based studies to assess age-related rectified lean tissue mass loss.

摘要

目的

双能 X 射线吸收法（DXA）测定的四肢瘦体组织质量（aLM）用于诊断肌少症。然而，DXA 测定的 aLM 包括非骨骼肌成分，如脂肪组织脂肪细胞的无脂肪成分。如果不考虑这些成分，它们可能会导致脂肪组织质量较高的个体的 aLM 假性增加。B 型超声能准确测量老年人的肌肉大小。我们试图建立基于回归的预测方程，以使用 B 型超声估计 DXA 校正的四肢瘦体组织质量（即 DXA 测定的 aLM 减去四肢无脂肪脂肪组织（aFFAT）；简称 aLM 减去 aFFAT）。

设计

横断面研究。

测量

389 名日本老年人（年龄 60 至 79 岁）自愿参加了这项研究。使用 DXA 测量 aLM，使用超声测量 9 个部位的肌肉厚度（MT）。使用普通最小二乘多元线性回归模型，根据性别、年龄和不同的肌肉厚度乘以身高来预测 aLM 减去 aFFAT。基于先前的研究，我们选择使用四肢上下 4 个部位（4 部位 MT 模型）和上肢 1 个部位（1 部位 MT 模型）来开发预测模型。

结果

线性预测模型（4 部位 MT 模型；R2=0.902，调整 R2=0.899，1 部位 MT 模型；R2=0.868，调整 R2=0.866）被发现稳定且准确，可用于估计 aLM 减去 aFFAT。Bootstrapping（n=1000）得到的乐观值分别为 0.0062（4 部位 MT 模型）和 0.0036（1 部位 MT 模型）。