Socioeconomic Status and Health: A Role for Immune Function?

Abstract

The goal of this dissertation is to present new evidence on the role of immune function as a biological mechanism that propagates health disparities.

Chapter 1 assesses whether biomarkers of inflammation can account for the relationship between educational attainment and mortality among older adults in Moscow, Russia. This is the first study of socioeconomic status and mortality to evaluate a number of biomarkers representing multiple biological systems in Russia. I find that biomarkers of inflammation account for the largest share of the education-mortality link in comparison to biomarkers that represent other biological systems.

In Chapter 2, I examine whether inflammation predicts cognitive decline among healthy older adults in Taiwan. The data I use are richer than previous studies on this topic: I include less commonly collected biomarkers of inflammation measured at two points in time, and cognitive function assessments from up to three time points. This chapter represents the first study of inflammation and subclinical cognitive decline in an East Asian population. I find no evidence that inflammation predicts cognitive decline, suggesting that the link between inflammation and clinical cognitive impairment does not generalize to subclinical cognitive decline among healthy adults.

In Chapter 3, I investigate the association between SES and the herpesvirus cytomegalovirus (CMV) among adults in Detroit, Michigan. Infection with CMV is a risk factor for mortality and many chronic diseases of aging. This is the first study to examine both CMV infection and levels of antibodies to CMV in relation to adult SES in a relatively deprived U.S. urban setting. I find that lower SES is associated with higher odds of CMV seropositivity, but not with CMV antibody levels among the infected.

These results provide evidence in favor of the hypothesized linkage between SES, immune function and health, although the strength of this linkage depends on the population and health measure under study. I find evidence that SES is linked to a key measure of immune function, and that immune function may be an important biological pathway between SES and mortality. I find no evidence of a relationship between immune function and subclinical cognitive change.