The Determinants and Consequences of Cognitive Aging: Evidence and Implications for Public Policy
Date of Award
Spring 2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Public Health
First Advisor
Chen, Xi
Abstract
Cognitive functioning is critical as in our daily life a host of complex and high-stakes decisions must be made and a wide spectrum of daily activities rely on cognitive health. Deterioration in cognition can greatly affect individuals’ decision-making, independent living, and wellbeing; and the presentation of cognitive impairment or dementia may impose substantial burdens on individuals, families, as well as the whole society. Given the long preclinical stages of the disorders and the life-long impacts of social, cultural, and environmental factors, public policies should be promoted to intervene early and strategically for population with different needs and contexts. To this end, my dissertation explored three understudied research questions on cognitive aging. The first project examines the extent to which early-life circumstances may individually and collectively contribute to the large and persistent racial disparities in cognitive outcomes between non-Hispanic White and Black older adults in the United States. Blinder-Oaxaca Decomposition is used to quantify the early-life contributions. Leveraging comprehensive life history data from the Health and Retirement Study (HRS), my analysis unveils significant racial disparities in both early-life circumstances and cognitive outcomes in later life. I demonstrate that early-life disparities account for a substantial portion of the racial disparities in later-life cognition. Overall, differences in early-life circumstances are associated with 61.5% and 82.3% of the racial disparities in cognitive score and cognitive impairment, respectively. In multivariable analyses, I show that early-life educational experience is associated with 35.2% of the disparities in cognitive score and 48.6% in cognitive impairment. Notably, school racial segregation (i.e., all segregated schooling before college) is associated with 28.8%-39.7% of the racial disparities in cognition. The findings are consistent in a series of sensitivity analyses. These findings underscore the critical importance of promoting equitable education, not only for immediate school performance but also for mitigating disparities that persist throughout individuals’ lifespans. The second project explores how promoting children’s education through educational reform help to delay parental cognitive aging, by exploiting a quasi-experiment (i.e., Compulsory Schooling Law) in China. Promoting children’s education can be an important policy option in developing countries, where older generations tend to be less educated and public resources are limited; and the evidence may increase the rationale for robust investment in childhood education. Specifically, this study provides novel evidence on the upward spillover effect of increasing children’s education on parents’ cognitive aging and investigates changes in family caring arrangements that may explain the effect. Using multiple waves of China Health and Retirement Longitudinal Study (CHARLS) to model trajectories of cognitive aging, and exploring temporal and geographic variations in the Compulsory Schooling Law enforcement in a Two-Stage Least Squares (IV/2SLS) framework, I show that increases in children’s education impose larger effect on reducing level of cognitive deficit among older parents than smoothing their trajectories of cognitive decline. The effect is also larger on crystal intelligence than on fluid intelligence. While both more educated and less educated children benefit parental cognitive health, they demonstrate some within-family coordination. Specifically, more educated children tend to offer older parents more resource-related support, including financial transfer, household appliances and equipment, while less educated children often engage in more time-related support, such as living relatively close to parents, providing informal care and decision-making support, not leaving grandchild care burden to parents. These findings offer insights into leveraging the intergenerational spillover effect of educational policy to delay cognitive aging and related diseases. The third project turns to the consequences of cognitive aging, which can occur years before or after the onset of dementia. Identifying early signals of dementia risk may offer people more time to prepare for the future, helping to delay the onset or slow the progression of dementia. Using the 1995-2018 waves of the HRS, I offer novel evidence on the impacts of dementia on a rich set of preventive care utilization and health behaviors. Leveraging both within- and between-individual variations in an event study design, I characterize long-term dynamic changes in preventive care and health behaviors relative to the incidence of dementia and find early behavioral indicators of the disorder. I show that relative to the group of people who never develop dementia during the study periods, people with dementia have consistent and escalating declines in the use of cholesterol test, dental visit, prostate test and mammogram around the incidence of dementia. Significant declines are also found in physical activities and social engagement. Importantly, I demonstrate that the behavioral changes can occur up to 6 years before the incidence of dementia; and these patterns are absent in other chronic or acute conditions. The results are robust to sample selection, model specification, and the further control of aging and cohort effects. Overall, these findings highlight the salient impact of dementia risk on preventive care utilization and health behaviors, which may increase individuals’ vulnerability to health shocks. Detecting early signals of dementia and facilitating targeted interventions are thus called for to prevent individuals from adverse behavioral and health consequences.
Recommended Citation
Lin, Zhuoer, "The Determinants and Consequences of Cognitive Aging: Evidence and Implications for Public Policy" (2024). Yale Graduate School of Arts and Sciences Dissertations. 1258.
https://elischolar.library.yale.edu/gsas_dissertations/1258
