The impact of cumulative socioeconomic inequalities on physical functioning, self-rated health, and depression among older adults

Socioeconomic inequalities have been viewed as significant contributors to health disparities. However, little is known about the impact of cumulative socioeconomic inequalities on physical functioning, self-rated health, and depression across time, especially in later life. In addition, despite a strong connection between socioeconomic inequalities and the presence of private health insurance, few studies have examined how lack of private health insurance affects individuals' health trajectories. Thus, this study focuses on the impact of socioeconomic inequalities and lack of private health insurance on physical functioning, self-rated health, and depression using longitudinal panel data from the Health and Retirement Study (HRS). The latent growth curve model was conducted in three steps: unconditional model, conditional model, and multiple group analysis. First, the unconditional growth curve model presented that individuals' physical functioning, self-rated health, and depression tend to worsen as people age. However, significant variability in the initial level of health outcomes and their rate of change among individuals were found. Second, the conditional growth curve model was conducted to test potential covariate effects on this variability. Results from the conditional model showed that higher level of income and assets significantly predicted better physical functioning and self-rated health but less depressive symptoms. In particular, increases in income or assets significantly predicted slower worsening in physical functioning, self-rated health, and depression. However, iii higher level of education was a significant predictor for better self-rated health and less depression at baseline but not for physical functioning. In addition, having private health insurance significantly predicted better physical functioning, self-rated health, and less depressive symptoms at baseline. In particular, decline in physical functioning was slower among those who have private health insurance over time. Third, the multiple group analysis was conducted to examine potential moderating effects of gender and race on health trajectories. Results from the multiple group analysis showed that economic status had greater impact on females' declines in physical functioning, self-rated health, and depression than on males'. Despite lower initial level of physical functioning and self-rated health among Blacks than among Whites, they were less likely to suffer rapid declines in physical functioning and self-rated health after controlling for socioeconomic status. These results indicated that Blacks might have resilience factors such as religious activities and social support networks buffer health declines. Specific implications for social policy, practice, and research are discussed.