Cawthon Peggy M, Blackwell Terri L, Kritchevsky Stephen B, Newman Anne B, Hepple Russell T, Coen Paul M, Goodpaster Bret H, Duchowny Kate, Hetherington-Rauth Megan, Mau Theresa, Shankaran Mahalakshmi, Hellerstein Marc, Evans William J, Cummings Steven R
Research Institute, California Pacific Medical Center, San Francisco, CA, USA.
Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA.
medRxiv. 2023 Nov 10:2023.11.09.23298303. doi: 10.1101/2023.11.09.23298303.
Different measures to assess muscle size - magnetic resonance (MR) derived thigh muscle volume and d3-creatine dilution derived muscle mass (DCr muscle mass) - may have similar associations with strength, power, physical performance, fitness, and functional limitations in older adults.
Men (N=345) and women (N=482) aged ≥70 years from the Study of Muscle, Mobility and Aging completed exams including leg extension strength (1-repetition max) and cardiopulmonary exercise testing to assess fitness (VOpeak). Correlations and adjusted regression models stratified by sex were used to assess the association between muscle size measures and study outcomes; we tested for sex interactions.
DCr muscle mass and MR thigh muscle volume were correlated (men: r=0.62, women: r=0.51, p<.001). Lower DCr muscle mass and lower MR thigh muscle volume were associated with lower strength and lower VOpeak in both men and women; DCr muscle mass was more strongly associated with strength in men than in women (p-int<0.05). There were correlations, though less consistent, between muscle size or mass with physical performance and function. Associations between the muscle size measures and the study outcomes occasionally varied by sex, and associations of MR thigh muscle volume were, at times, slightly more strongly associated with the study outcomes than was DCr muscle mass.
Less muscle -measured by either DCr muscle mass or MR thigh muscle volume - was associated with lower strength and worse performance. Varied associations by sex and assessment method suggest consideration be given to which measurement to use in future studies.
评估肌肉大小的不同方法——磁共振（MR）衍生的大腿肌肉体积和3-肌酸稀释衍生的肌肉质量（DCr肌肉质量）——在老年人中可能与力量、功率、身体表现、体能和功能受限有相似的关联。
来自肌肉、 Mobility和衰老研究的年龄≥70岁的男性（N = 345）和女性（N = 482）完成了包括腿部伸展力量（1次重复最大值）和心肺运动测试以评估体能（VO峰值）的检查。使用按性别分层的相关性和调整回归模型来评估肌肉大小测量与研究结果之间的关联；我们检验了性别交互作用。
DCr肌肉质量与MR大腿肌肉体积相关（男性：r = 0.62，女性：r = 0.51，p <.001）。较低的DCr肌肉质量和较低的MR大腿肌肉体积与男性和女性较低的力量和较低的VO峰值相关；DCr肌肉质量与男性力量的关联比女性更强（p值交互作用<0.05）。肌肉大小或质量与身体表现和功能之间存在相关性，尽管不太一致。肌肉大小测量与研究结果之间的关联偶尔因性别而异，并且MR大腿肌肉体积的关联有时与研究结果的相关性略强于DCr肌肉质量。
无论是通过DCr肌肉质量还是MR大腿肌肉体积测量，较少的肌肉都与较低的力量和较差的表现相关。性别和评估方法的不同关联表明，在未来的研究中应考虑使用哪种测量方法。
