Abstract
Currently, about one in every eight Americans is age 65 or older; by the year 2050, it will be one in five people. Given this graying of the population, research into successful aging is of increasing relevance. The question of how to precisely define successful aging, however, has not been completely answered. Likewise, the role of vascular risk factors, subclinical vascular brain damage, and other biopsychosocial characteristics in normal cognitive aging are not well understood. This Dissertation focused on the identification of some of the physiological, behavioral, and social risk factors that distinguish people able to maintain extraordinary health at an advanced age. Specifically, we aimed to create an ecologically valid definition of successful aging that incorporates both physical well-being and cognitive abilities, and to report the prevalence of successful cognitive aging in a population-based multi-ethnic cohort of older adults. We sought to describe how the prevalence varies by several sociodemographic and psychosocial determinants, and to investigate global vascular risk, depressive symptomatology, and MRI markers of subclinical vascular brain damage as correlates of successful cognitive aging. We observed the prevalence of successful cognitive aging to be 37% in the study sample (N=1,162) of a diverse racial/ethnic population in Northern Manhattan (NYC, NY). The prevalence decreased with increasing age; we did not observe any differences by racial/ethnic group, but did note a lower prevalence with lower socioeconomic status. Several social resources and self-reported quality of life were related to successful cognitive aging, and appeared more important than demographic variables alone. We found that the likelihood of successful cognitive aging decreases with increasing global vascular risk score, more severe depressive symptomatology, and greater white matter damage. The field of successful aging requires further study. Consideration of such biopsychosocial factors as socioeconomic status, social support, quality of life, and depressive symptoms alongside novel indicators of disease and disability including global vascular risk and white matter hyperintensity burden is essential. It may lead to a more robust definition of successful cognitive aging replete with opportunities to modify the aging process, as many of the factors investigated in this study are modifiable.