Lifecourse Psychosocial Factors and Racial Disparities in Cognitive Aging

Abstract

Poor cognitive function has been linked to lower quality of life and daily functioning. Racial disparities in cognitive function have been widely documented, but factors that drive the disparities are unclear. Leveraging data from the Midlife Development in the United States Study (MIDUS) and the MIDUS Refresher study, this dissertation assessed the associations between lifecourse psychosocial factors and cognitive outcomes and their roles in racial disparities in cognitive function. Specifically, paper 1 of this dissertation investigates associations of cumulative stress exposures, as well as specific patterns of stress exposures across the life course, with both level of and change in cognitive function. Paper 2 determined the extent to which psychosocial stressors explain racial disparities in executive function and episodic memory. Paper 3 determined the associations between positive childhood experiences and cognitive function between Black and White participants. Paper 1 found that higher cumulative stress exposure was associated with lower executive function and episodic memory. Baseline executive function and episodic memory were lower among those with high stress only in childhood, only in adulthood, and both, compared with those without high stress in childhood or adulthood. However, there was no evidence that changes in executive function and episodic memory differed across levels of cumulative stress exposures. Paper 2 showed that relative to White participants, Black participants had lower levels of cognitive function and were exposed to high levels of cumulative stress exposures. Importantly, cumulative stress exposures explained a modest proportion of Black-White disparities in executive function and episodic memory. Paper 3 revealed that levels of cognitive function were higher among those who reported more positive childhood experiences. However, the associations between positive childhood experiences and executive function were only evident among White participants, not Black participants. Taken together, this dissertation advances our understanding of the associations of psychosocial stressors and positive childhood experiences with cognitive outcomes in adulthood. These findings highlight the important roles of psychosocial factors in racial disparities in cognitive outcomes and pave the way for future research investigating mechanisms underlying psychosocial factors and disparities in cognitive outcomes.