Abstract: Objective To investigate the mediating role of serum vitamin D₃ levels in the relationship between depression severity and cognitive function among elderly individuals with mild cognitive impairment (MCI). Methods A total of 477 elderly individuals with MCI who met the inclusion criteria were recruited via convenience sampling from the Health Service Center of Matang Street Community, Yijiang District, Wuhu City, Anhui Province, between January 2023 and December 2023. Data were collected using a general questionnaire, the Geriatric Depression Scale, and the Mini-Mental State Examination. Serum vitamin D₃ levels were measured for all participants. Pearson correlation analysis was conducted using SPSS 27.0, and the mediating effect was analyzed using Model 4 in the Process plugin. Results Cognitive function in elderly individuals with MCI was negatively correlated with depression severity (P<0.001) and positively correlated with serum vitamin D₃ levels (P<0.05). Bootstrap test results indicated that serum vitamin D₃ levels partially mediated the relationship between depression and cognitive function in elderly individuals with MCI, with a mediating effect of -0.019 (95% CI: -0.038 to -0.005), accounting for 8.02% of the total effect. Conclusion Serum vitamin D₃ levels play a partial mediating role in the relationship between depression and cognitive function in elderly individuals with MCI.

Key words: Mild cognitive impairment, Depression, Cognitive function, Vitamin D, Mediation effect

摘要： 目的 探索轻度认知障碍（Mild cognitive impairment,MCI）老年人群中血清维生素D₃水平在抑郁程度与认知功能间的中介作用。方法 采用便利抽样法,选取2023年1月~2023年12月在安徽省芜湖市弋江区马塘街道社区卫生服务中心体检符合入组标准的477例MCI老年人,采用一般调查问卷、老年抑郁量表和简易智力状态检查量表对研究对象进行调查,并检测其血清维生素D₃水平。采用SPSS 27.0进行Pearson相关分析,运用Process插件中的Model 4进行中介效应分析。结果 MCI老年人群的认知功能与抑郁程度呈显著负相关（P<0.001）,与血清维生素D₃水平呈正相关（P<0.05）。Bootstrap检验结果显示,血清维生素D₃水平在MCI老年人群抑郁程度与认知功能间的中介效应为-0.019,95%CI为（-0.038~-0.005）,中介效应占总效应的8.02%。结论 血清维生素D₃水平在MCI老年人群抑郁与认知功能间起部分中介作用。

关键词: 轻度认知障碍, 抑郁, 认知功能, 维生素D, 中介效应