Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Tobago Health Studies Office, Scarborough, Trinidad and Tobago.
Obesity (Silver Spring). 2023 Sep;31(9):2398-2406. doi: 10.1002/oby.23816. Epub 2023 Jul 20.
Skeletal muscle adiposity (myosteatosis) is recognized as a major risk factor for cardiometabolic diseases, and it increases with aging. The relationship of myosteatosis with cognitive impairment is unknown.
The association of calf myosteatosis (measured by computed tomography-derived skeletal muscle density; higher values indicate less myosteatosis) with cognitive function was examined among 626 African Caribbean women who were aged 40 to 84 years, a population highly vulnerable to increased myosteatosis. Cognition was assessed by the Digit Symbol Substitution Test (DSST), a test of information processing speed (higher scores indicate better performance). Linear regression was used to assess the association of muscle density with DSST.
Adjusting for age, education, muscle area, BMI, hypertension, diabetes, cardiovascular event history, lifestyle factors, lipid-lowering medication use, and menopausal status, a one-SD lower muscle density was associated with a 1.69-point lower DSST score (p = 0.002). BMI, diabetes, and hypertension interactions were not statistically significant, suggesting that the main association was not moderated by overall obesity or cardiometabolic diseases.
These findings suggest that greater myosteatosis is associated with slower information processing speed, an early indicator of cognitive impairment. Further studies are needed to establish this association in this and other populations using an expanded battery of cognitive tests with longitudinal follow-up and to identify the biological mechanisms underlying this relationship.
骨骼肌脂肪增多（肌内脂肪增多）被认为是心血管代谢疾病的一个主要危险因素，且其随年龄增长而增加。肌内脂肪增多与认知障碍的关系尚不清楚。
在一个非常容易发生肌内脂肪增多的人群中，对 626 名年龄在 40 至 84 岁的非裔加勒比妇女进行了小腿肌内脂肪（通过计算机断层扫描得出的骨骼肌密度来衡量；数值越高表示肌内脂肪越少）与认知功能的相关性研究。认知功能通过数字符号替代测试（DSST）来评估，该测试是一种信息处理速度测试（得分越高表示表现越好）。线性回归用于评估肌肉密度与 DSST 之间的关系。
在校正年龄、教育程度、肌肉面积、BMI、高血压、糖尿病、心血管事件史、生活方式因素、降脂药物使用和绝经状态后，肌肉密度每降低一个标准差，DSST 得分就会降低 1.69 分（p=0.002）。BMI、糖尿病和高血压的交互作用没有统计学意义，这表明主要关联不受整体肥胖或心血管代谢疾病的调节。
这些发现表明，更多的肌内脂肪增多与信息处理速度较慢有关，而信息处理速度较慢是认知障碍的早期指标。需要进一步的研究来确定这种关联在该人群和其他人群中的存在，方法是使用扩展的认知测试组合进行纵向随访，并确定这种关系背后的生物学机制。
