Background How magnetic resonance (MR) derived thigh muscle volume and d3-creatine dilution derived muscle mass (D3Cr muscle mass) differentially relate to strength, fitness, and other functional in older adults - and whether associations vary by sex - is not known. Methods Men (N=345) and women (N=482) aged ≥70 years from the Study of Muscle, Mobility and Aging completed leg extension strength (1-repetition max) and cardiopulmonary exercise testing to assess fitness (VO2peak). Correlations and adjusted regression models stratified by sex were used to assess the association between muscle size measures and study outcomes and sex interactions. Results D3Cr muscle mass and MR thigh muscle volume were correlated (men: r=0.62, women: r=0.51, p<.001). Each standard deviation decrement in D3Cr muscle mass was associated with lower 1-RM strength (-14 kg men, -4 kg women, p<.001 for both; p-interaction=0.003) and lower VO2peak (-79 mL/min men, -30 mL/min women, p<.001 for both, p interaction: 0.016). Each SD decrement in MR thigh muscle volume was also associated with lower strength (-32 kg men, -20 kg women, p<0.001 for both; p-interaction 0.139) and lower VO2peak (-217 mL/min men, -111mL/min women, p<.001 for both, p interaction: 0.010). There were associations, though less consistent, between muscle size or mass with physical performance and function; associations varied by sex. Conclusions Less muscle –measured by either D3Cr muscle mass or MR thigh muscle volume - was associated with lower strength and fitness. Varied associations by sex and assessment method suggest consideration be given to which measurement to use in future studies.

中文翻译：

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SOMMA 研究中 D3Cr 肌肉质量和 MR 大腿肌肉体积与老年人的力量、力量、身体表现、健康和限制之间的关联

背景 磁共振 (MR) 得出的大腿肌肉体积和 d3-肌酸稀释得出的肌肉质量 (D3Cr 肌肉质量) 与老年人的力量、健身和其他功能有何不同相关性 - 以及这种关联是否因性别而异 - 尚不清楚。方法 年龄≥70 岁的男性（N=345）和女性（N=482）通过肌肉、活动性和衰老研究完成腿部伸展力量（最多重复 1 次）和心肺运动测试以评估健康状况（VO2peak）。按性别分层的相关性和调整回归模型用于评估肌肉大小测量与研究结果和性别相互作用之间的关联。结果 D3Cr 肌肉质量和 MR 大腿肌肉体积相关（男性：r=0.62，女性：r=0.51，p＜.001）。D3Cr 肌肉质量的每个标准差减量均与较低的 1-RM 力量（-14 kg 男性，-4 kg 女性，p<.001；p-交互=0.003）和较低的 VO2peak（-79 mL/min 男性）相关，-30 mL/min 女性，两者 p<.001，p 交互作用：0.016）。MR 大腿肌肉体积的每个 SD 减少也与较低的强度（-32 kg 男性，-20 kg 女性，两者 p<0.001；p 交互作用 0.139）和较低的 VO2peak（-217 mL/min 男性，-111 mL/min）相关。女性最少，两者 p<.001，p 交互作用：0.010）。肌肉大小或质量与身体表现和功能之间存在关联，但不太一致。关联因性别而异。结论 较少的肌肉（通过 D3Cr 肌肉质量或 MR 大腿肌肉体积测量）与较低的力量和体能相关。性别和评估方法的不同关联建议考虑在未来的研究中使用哪种测量方法。