Longitudinal Studies Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
Laboratory of Behavioral Neuroscience, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
J Gerontol A Biol Sci Med Sci. 2021 Jan 18;76(2):286-290. doi: 10.1093/gerona/glaa095.
Muscle strength and brain volume decline with aging; changes in the brain manifested as change in volume may play a role in age-related strength loss, but this hypothesis has never been tested longitudinally. We examined longitudinal associations between brain volume changes and knee extension peak torque change in participants of the Baltimore Longitudinal Study of Aging.
Brain volumes and isokinetic concentric knee extension peak torque at 30 deg/s were measured in 678 participants (55.2% women; baseline age, 50.1-97.2 years; median follow-up time in those who visited two or more times (n = 375, 4.0 [interquartile range {IQR}, 2.3-5.0] years). Correlations between longitudinal changes in brain volumes and knee extension peak torque were examined using bivariate linear mixed-effects models, adjusted for baseline age, sex, race, education, and intracranial volume.
Greater decline in muscle strength was associated with greater atrophies in global gray matter, temporal lobe, frontal gray matter, temporal gray matter, superior frontal gyrus, inferior frontal gyrus, supramarginal gyrus, middle temporal gyrus, inferior temporal gyrus, and occipital pole (r ranging from .30 to .77, p < .05). After multiple comparison adjustment, only larger decrease in middle temporal gyrus remained significantly related to larger decrease in muscle strength (q = 0.045).
In older adults, declines in knee extension muscle strength co-occurred with atrophies in frontal, temporal, and occipital gray matter. These findings support the idea that age-related knee extension muscle strength is linked with atrophy in some specific brain regions related to motor control.
肌肉力量和大脑体积随年龄增长而下降；大脑的变化表现为体积的变化，可能在与年龄相关的力量下降中发挥作用，但这一假设从未被纵向研究检验过。我们研究了巴尔的摩老龄化纵向研究参与者的大脑体积变化与膝关节伸肌峰值扭矩变化之间的纵向关联。
在 678 名参与者（55.2%为女性；基线年龄 50.1-97.2 岁；中位数随访时间为两次或两次以上（n=375 次，4.0[四分位距 {IQR}，2.3-5.0]年））中测量了大脑体积和等速向心膝关节伸肌峰值扭矩。使用双变量线性混合效应模型，调整基线年龄、性别、种族、教育和颅内体积，检查大脑体积和膝关节伸肌峰值扭矩的纵向变化之间的相关性。
肌肉力量下降越大，与全脑灰质、颞叶、额叶灰质、颞叶灰质、额上回、额下回、缘上回、颞中回、颞下回和枕极的萎缩程度越大（r 值范围为 0.30-0.77，p<0.05）。经过多次比较调整，只有颞中回的下降幅度与肌肉力量的下降幅度显著相关（q=0.045）。
在老年人中，膝关节伸肌力量的下降与额叶、颞叶和枕叶灰质的萎缩同时发生。这些发现支持这样一种观点，即与年龄相关的膝关节伸肌力量与与运动控制相关的一些特定大脑区域的萎缩有关。
