The impact of neighborhood greenspace on cognitively healthy life years and structural markers of brain health

点击翻译按钮获取中文摘要

PROJECT SUMMARY Consistently, studies indicate there are stark racial differences in the prevalence of Alzheimer’s Disease and related dementias (ADRDs), wherein older Black individuals are about twice as likely to have ADRDs as compared to older White individuals. Racial residential segregation is considered a fundamental driver of racial disparities in health, as historically disadvantaged neighborhoods are associated with less access to and differing quality of resources that promote health and wellness. Specific aspects of disadvantaged and historically redlined neighborhoods, including decreased exposure to greenspace, are associated with poorer cognitive function. Targeting such environmental risk factors for ADRDs is appealing as they are highly modifiable, unlike many individual-level risk factors. This study will utilize secondary data from the Health, Aging and Body Composition Study, a population-based, biracial sample of adults aged 70-79 at entry. The overall objective of this application is to examine the influence of exposure to residential greenspace that contributes to time spent in cognitive health among older adults and to structural brain changes over time. Cognitively healthy life years (HLY), or years lived to the first occurrence of cognitive problems, is a metric that can facilitate better understanding of risk factors specifically associated with the length of time spent in years of cognitive health. This represents a substantive departure from the status quo by expanding the definition of “healthy” cognition into a person-centered metric more understandable to the individual, and better encapsulates burden as both a measure of morbidity and mortality. Relatedly, structural measures of brain health, such as magnetic resonance imaging biomarkers, are quantitative indicators of neuropathology that have prognostic significance for future time spent cognitively healthy. In Aim 1, I will determine the association between neighborhood greenspace and cognitively HLY. I hypothesize that individuals living in neighborhoods with greater residential greenspace will maintain more cognitively healthy life years, and this association will differ by race. In Aim 2, I will examine the association between greenspace and physical indicators of brain health. I hypothesize that individuals living in neighborhoods with greater residential greenspace will show a lower prevalence of neuropathology over time (measured by gray matter micro-structure and white matter hyperintensities), and this association will differ by race. In Aim 3, I will further characterize a widely-used composite greenspace measure using historical virtual audits, to identify the specific components of greenspace associated with healthy cognition. Identifying the impact of modifiable, environmental risk factors on cognition is necessary to inform future preventive interventions for healthy brain aging and public health recommendations; a strategic direction of the National Institute on Aging. This dissertation funding will provide the necessary foundation to reach my professional goals and make impactful contributions in the field of aging research, transitioning from predoctoral trainee to an independent research scientist.