Key modifiable factors in urban-rural differences in depression among older adults in China: A comparative study between China and the United States.

Objectives: Urban-rural differences in depression are evident among older adults in China but not in the United States. By comparing the two countries, this study aims to explore strategies for promoting regional equality in depression in China.

Methods: Data from the China Health and Retirement Longitudinal Study (CHARLS) and the Health and Retirement Study (HRS) were utilized. Longitudinal data were used to describe urban-rural differences in depression prevalence among older adults in China (2011-2020) and the United States (2010-2020). Cross-sectional data from 2018 (CHARLS: 9840 participants; HRS: 10,381 participants) were used to identify key modifiable factors. A random forest algorithm was employed to determine the most important factors influencing depression, and comparisons between the two countries were made to identify modifiable factors. Multivariate logistic regression was used to analyze the relationship between these key modifiable factors and depression. A mediation model was applied to assess the mediating role of key modifiable factors in the relationship between residence and depression.

Results: 1) From 2011 to 2020, Urban-rural differences in depression prevalence among older adults were observed in China, but not in the United States. 2) In both China and the U.S., the top five factors ranked by importance were activities of daily living disability (ADLs), instrumental activities of daily living disability (IADLs), pain levels, self-reported health (SRH), and age. However, Urban-Rural Differences in ADLs, IADLs, and SRH were present in China but not in the United States. 3) ADLs, IADLs, and SRH collectively mediated 31.6 % (95 % CI: 0.268 - 0.360) of the relationship between residence and depression scores among older adults in China.

Conclusion: Urban-rural differences in physical health status (ADLs, IADLs, and self-reported health) among older adults in China are associated with Urban-Rural Differences in depression. The absence of such inequalities in the U.S. may offer insights for developing policies to promote regional equality in depression among older adults in China.