Socioeconomic Determinants of Health Disparities by Race and Ethnicity: the Mediating Role of Social, Psychological and Behavioral Factors

Socioeconomic status (SES) is inversely related to health status. Disparities in health status among races and ethnic groups are partly attributable to differences in SES, but the indirect pathways by which SES may influence health status are not widely studied. Using the Health and Retirement Study (HRS) data, this dissertation examined the pathways by which SES, via social, psychological, and behavioral factors predicted physical impairment and overnight hospitalization, and asked whether these indirect relationships differed by race/ethnicity. The HRS is a nationally representative multistage area probability sample administered biennially to respondents over the age of 51 and their spouses. Data collected between 2002 and 2010, covering five waves of the original HRS cohort born between the years 1931 and 1941, were used. Two analysis approaches, Structural Equation Modeling (SEM) and Reconstructability Analysis (RA), were used. Adjustments for the complex survey design were made in the SEM analysis, whereas, data were matched for the RA method using propensity scores. Results of the SEM analyses supported most of the hypothesized indirect relationships between SES variables and physical impairment via social and psychological factors, but the indirect effect of SES on physical impairment via behavioral factors was weak. Multiple group analyses of path equality using nested chi-square tests indicated that the indirect effect of SES on physical impairment status did not vary by race/ethnicity. Social, psychological and behavioral factors were weakly related to overnight hospitalization, and SES was not indirectly related to overnight hospitalization. While these results supported several hypothesized indirect relationships between SES variables and physical health status, the indirect effect sizes were small. However, because this study examined predictive paths across groups rather than compare mean differences, and because indirect effects are products of individual path coefficients, small effect sizes are not uncommon in mediation analysis. Moreover, over a lifetime, small effects may gradually add up increasing group differences in health status with greater benefits accruing to higher SES individuals via social and psychological factors, as observed in this study. The RA results showed that indirect relationships between SES and physical impairment were similar across races/ethnicities for identical variables with a few exceptions. In several cases, however, selected SES variables related to social and psychological variables were different for different groups. Cross-sectional indirect relationships were stronger than longitudinal indirect relationships. As in the SEM study, SES was not related to physical impairment via behavioral factors; and, across groups, SES was also not related to overnight hospitalization either directly or via social, psychological or behavioral factors. Variables predicting physical impairment exhibited differences across groups; these differences were detected because RA, unlike SEM, used disaggregated social, psychological and behavioral factors. Where predictive variables overlapped, the effects of identical independent variable (IV) states on physical impairment were similar across groups with a few exceptions. In summary, both the SEM and RA results indicated that SES was indirectly related to physical impairment via social and psychological factors, and results from both methods also showed that SES was not indirectly related to overnight hospitalization via these factors. SEM did not find that these indirect effects varied by race/ethnicity; RA found a few differences