Bidirectional associations between socioeconomic status, physical activity, and depressive symptoms in middle-aged and older adults: A cross-lagged prospective cohort study.

OBJECTIVE: This study aims to investigate the bidirectional relationship and cascading effects of socioeconomic status (SES) and depression symptoms in middle-aged and older adults, with physical activity acting as a mediator.

METHODS: A total of 23,747 adults (age ≥ 45 years) from the Health and Retirement Study (HRS), the English Longitudinal Study of Ageing (ELSA), the Mexican Health and Ageing Study (MHAS), and the Survey of Health, Ageing and Retirement in Europe (SHARE) participated in this six-year longitudinal study. Socioeconomic status was categorized using latent class analysis. Physical activity depends on participants' frequency over the past two years. The Center for Epidemiologic Studies Depression (CESD) Scale and the European Depression (EURO-D) Scale was used to assess depressive symptoms. Cross-lagged models examined bidirectional associations.

RESULTS: After adjusting for potential covariates, there was strong continuity across the three time points for socioeconomic status, physical activity, and depressive symptoms. Socioeconomic status and physical activity positively predicted each other, while depressive symptoms were associated with lower levels of physical activity.

LIMITATIONS: The limitations of this study include the exclusion of the indirect selection hypothesis and the reliance on self-reported depressive symptoms.

CONCLUSION: Physical activity mediates the relationship between depressive symptoms and subsequent socioeconomic status, with depression-related risks potentially having a greater impact on the socioeconomic status of middle-aged and older single women in developed countries, highlighting the need to consider additional factors in reducing depression risk among older adults.