Background: More than 30 million older people in China live alone. Research has shown that living alone can lead to poor mental health and that there are mediating variables, such as healthy diet, between living alone and mental health. Therefore, it is important to examine the role of these mediating variables between living alone and mental health to help us develop cost-effective mental health interventions.

Methods: We used the multiple regression method in the R software to test the effect of living arrangements on depression by placing the living arrangements variable, the covariates, and the healthy diet variables into the regression equation. We then used the structural equation method with the R software package lavaan to derive the path coefficients of living arrangements on depression scores through the three mediating paths of fruits, vegetables, and nuts consumption. We used bootstrapping to derive confidence intervals for the coefficients.

Results: Multiple regression results showed that the coefficient of the effect of living alone on depressive symptoms was 1.02. At the same time, all three variables of a healthy diet can alleviate depression, i.e., consuming more fruits, vegetables, and nuts helped to reduce depression scores among older adults. In the mediation analysis, living alone affects the mental health of older adults through three channels, namely, fruit consumption, vegetable consumption, and nuts consumption, respectively, and the indirect effects of these three channels accounted for 15.47% of the total impact of living alone on depression scores of older adults, with vegetable intake having the most significant effect on depression scores, accounting for 8.35% of the total impact, followed by nuts intake and fruits intake.

Conclusion: Older people living alone are a vulnerable group with poor mental health and require a variety of interventions to improve their mental health. Healthy eating is one possible avenue of intervention; the Government should take diversified initiatives to enhance the healthy diet of older persons living alone.

Keywords: depressive symptoms; healthy diet; living alone; mental health; older adults.

Copyright © 2025 Zheng and Ni.

背景： 在中国，超过3000万老年人独居。研究表明，独居可能导致精神健康状况不佳，并且在独居与心理健康之间存在一些中介变量，如健康饮食等。因此，探讨这些中介变量在独居和心理健康之间的角色对于制定成本效益高的心理健康干预措施至关重要。

方法： 我们使用R软件中的多元回归法来测试居住安排对抑郁症状的影响，将居住安排、协变量以及健康饮食等因素放入回归方程中。接着，我们利用R软件包lavaan的结构方程方法导出通过水果、蔬菜和坚果摄入三条中介路径的生活方式与抑郁分数之间的通径系数，并采用自助法（bootstrapping）来推导系数的置信区间。

结果： 多元回归结果显示，独居对抑郁症状的影响系数为1.02。同时，三种健康饮食变量都可以减轻抑郁：即食用更多的水果、蔬菜和坚果有助于降低老年人群的抑郁分数。在中介分析中发现，独居通过三条渠道影响老年人的精神健康，分别是水果摄入量、蔬菜摄入量和坚果摄入量；这三条间接效应合计占到独居对老年人群抑郁分数总影响的15.47%，其中蔬菜摄入的影响最大，占总影响的8.35%，其次是坚果摄入和水果摄入。

结论： 独居老人是一个心理健康状况较差且脆弱的人群，需要多种多样的干预措施来改善他们的精神健康。健康饮食可能是一种可行的干预途径；政府应当采取多样化举措以提升独居老年人的健康饮食水平。

关键词： 抑郁症状；健康饮食；独居；心理健康；老年人