Division of Geriatric Medicine, UNC School of Medicine, Chapel Hill, NC, USA.
Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
J Geriatr Psychiatry Neurol. 2024 Jul;37(4):272-281. doi: 10.1177/08919887231218087. Epub 2023 Nov 22.
Dementia affects 55 million people worldwide and low muscle mass may be associated with cognitive decline. Mid-arm muscle circumference (MAMC) correlates with dual-energy Xray absorptiometry and bioelectrical impedance analyses, yet are not routinely available. Therefore, we examined the association between MAMC and cognitive performance in older adults.
We included community-dwelling adults ≥55 years from the China Health and Nutrition Survey. Cognitive function was estimated based on a subset of the modified Telephone Interview for Cognitive Status (0-27, low-high) during years (1991, 1993, 1997, 2000, 2004, 2006, 2009, 2011, 2015, 2018). A multivariable linear mixed-effects model was used to test whether MAMC was associated with rate of cognitive decline across age groups and cognitive function overall.
Of 3702 adults (53% female, 63.2 ± 7.3 years), mean MAMC was 21.4 cm ± 3.0 and baseline cognitive score was 13.6 points 6.6. We found no evidence that the age-related rate of cognitive decline differed by MAMC ( = .77). Declines between 5-year age groups ranged from -.80 [SE (standard error) .18] to -1.09 [.22] for those at a mean MAMC, as compared to -.86 [.25] to -1.24 [.31] for those at a 1 MAMC 1 standard deviation above the mean. Higher MAMC was associated with better cognitive function with .13 [.06] higher scores for each corresponding 1 standard deviation increase in MAMC across all ages.
Higher MAMC at any age was associated with better cognitive performance in older adults. Understanding the relationship between muscle mass and cognition may identify at-risk subgroups needing targeted interventions to preserve cognition.
全球有 5500 万人患有痴呆症，肌肉量低可能与认知能力下降有关。上臂中部肌肉周长（MAMC）与双能 X 射线吸收法和生物电阻抗分析相关，但这些方法并不常用。因此，我们研究了老年人 MAMC 与认知表现之间的关系。
我们纳入了来自中国健康与营养调查的社区居住的≥55 岁成年人。认知功能是根据修改后的电话认知状态测试（0-27，低-高）的一个子集在不同年份（1991 年、1993 年、1997 年、2000 年、2004 年、2006 年、2009 年、2011 年、2015 年、2018 年）进行评估的。使用多变量线性混合效应模型来检验 MAMC 是否与不同年龄组的认知下降速度以及整体认知功能相关。
在 3702 名成年人（53%为女性，63.2±7.3 岁）中，平均 MAMC 为 21.4cm±3.0，基线认知评分为 13.6 分±6.6。我们没有发现 MAMC 与年龄相关的认知下降速度存在差异（ =.77）。在平均 MAMC 组中，每 5 岁年龄组的下降幅度在-0.80[标准误差（SE）.18]至-1.09[.22]之间，而在 MAMC 高出平均值一个标准差的组中，下降幅度在-0.86[.25]至-1.24[.31]之间。较高的 MAMC 与更好的认知功能相关，在所有年龄段中，MAMC 每增加一个标准差，认知评分相应增加 0.13[.06]。
在任何年龄，较高的 MAMC 与老年人的认知表现较好相关。了解肌肉量与认知能力之间的关系可能会确定需要有针对性干预措施来保护认知的高危亚组。
