Supplementary Material for: Association of Performance on Multiple Cognitive Domains with Sarcopenia Among Middle-aged and Older Adults

Introduction: The relationship between cognitive function and subsequent sarcopenia remains unclear. Therefore, this study aimed to examine the associations of performance on multiple cognitive domains with sarcopenia in the middle-aged and older adults.
Methods: This longitudinal analysis (wave 2011-2013) included 2934 participants from the CHARLS study. Sarcopenia was defined by the Asian Sarcopenia Working Group 2019 criteria. Cognitive function was measured by the Chinese version of the Mini-Mental State Examination (MMSE). Three interpretable techniques, namely SHapley Additive exPlanations (SHAP) and two built-in methods (coefficients of logistic regression and Gini importance of random forest), were used to assess the relationship between MMSE, its components (orientation, attention, episodic memory, and visuospatial ability) and sarcopenia. In addition, the association of MMSE score and its components with sarcopenia was further validated using stepwise regression.
Results: All interpretable methods showed that MMSE score was important predictors for sarcopenia, especially for SHAP (MMSE score ranked top one). For its components, episodic memory, visuospatial ability, and attention showed high predictive value compared with orientation. Stepwise regression analyses showed that MMSE score and its components of episodic memory and visuospatial ability were correlated with sarcopenia, with their odds ratios of 0.93 (95% CI: 0.91-0.96, p<0.001), 0.87 (95% CI: 0.82-0.93, p<0.001), and 1.32 (95% CI: 1.05-1.65, p=0.016), respectively.
Conclusions: Better cognitive function especially episodic memory and visuospatial ability was negatively associated with incident sarcopenia among community middle-aged and older adults.

引言：认知功能与后续发生的肌少症（sarcopenia）之间的关联尚不明晰。因此本研究旨在探讨中老年群体多项认知域表现与肌少症之间的关联。
方法：本项纵向分析（2011-2013年随访波次）纳入了来自中国健康与养老追踪调查（China Health and Retirement Longitudinal Study, CHARLS）的2934名受试者。肌少症按照亚洲肌少症工作组2019年诊断标准进行定义。认知功能采用中文版简易精神状态检查表（Mini-Mental State Examination, MMSE）进行评估。三种可解释性技术，即SHapley加性解释（SHapley Additive exPlanations, SHAP）以及两种内置分析方法（逻辑回归系数与随机森林基尼重要性），被用于评估MMSE及其各认知维度（定向力、注意力、情景记忆与视空间能力）与肌少症之间的关联。此外，本研究采用逐步回归法进一步验证了MMSE总分及其各认知维度与肌少症之间的关联。
结果：所有可解释性分析方法均显示，MMSE总分是肌少症的重要预测因子，其中SHAP分析的结果尤为显著（MMSE总分位列预测因子首位）。相较于定向力维度，情景记忆、视空间能力与注意力均表现出较高的预测价值。逐步回归分析结果显示，MMSE总分以及情景记忆、视空间能力维度与肌少症存在显著关联，其优势比分别为0.93（95%置信区间：0.91~0.96，P<0.001）、0.87（95%置信区间：0.82~0.93，P<0.001）与1.32（95%置信区间：1.05~1.65，P=0.016）。
结论：社区中老年群体中，更佳的认知功能（尤其是情景记忆与视空间能力）与新发肌少症呈负相关关联。