Aging Research Projects

A Binational Study of the Dementia Trajectory and Living Arrangements in the US and Mexico

PI: Jacqueline L. Angel, R03AG063183

The majority of previous research on health and support among racial/ethnic minorities in the U.S. in general and among Latinos in particular, and among peoples of Latin American countries relies on the idea of familismo, the idea that family need is put before individual need. Although there is evidence supporting the benefits of strong family ties have for helping older adults in these settings delay or avoid institutional care, this bi-national study is the first step toward assessing how Mexican and Mexican American families organize caregiving relationships for elderly family members who experience dementia. We will investigate trajectories of living arrangements and their relationship to dementia by employing the two largest epidemiologic surveys of older Mexican adults, the Hispanic Established Population of the Epidemiologic Study of the Elderly (H-EPESE) and the Mexican Health and Aging Study (MHAS). These studies contain a wide array of information regarding risk and protective factors for chronic diseases, dementia, dependency, socioeconomic characteristics, and living arrangements. One conceptual innovation of this research is that the model for understanding the relationship between living arrangements and disability will serve as a prototype for future research on the dementia-related disablement processes for other racial/ethnic minority groups and bi-national comparisons with Mexico. By exploring the changing need for, and availability of, support, as dementia progresses, we can make better conclusions about the number of older Latinos at risk of being left without sound support and, consequently, highly dependent on public resources. We will estimate at which point in the disablement process interventions are most needed. This project, by incorporating dementia, will also lead to the development of a more robust theoretical model for assessing disability and support need in older adults. Another innovative aspect of this research is the use of quantitative, longitudinal data to examine the relationship between dementia and the need for assistance in two prospective cohort studies of older Mexicans in Mexico and Mexican-origin adults in the United States. We will examine patterns of stability and change in living arrangements among individuals with and without dementia; the extent to which migration to and from the U.S. affects morbidity; health and socioeconomic status; and other proximal factors to account for any differences. A key methodological innovation of this project is its move from static cross-sectional analyses and standard growth models to growth mixture modeling (GMM), which allows us to examine greater diversity in the lived experiences of older peoples with dementia in both nations. Altogether, this work will provide a deeper understanding of the role of dementia in the long-term family caregiving experience of the Mexican-origin population in both Mexico and the United States, and highlight the role of migration and socioeconomic factors in shaping social resources in a time of need.

Social Networks and Well-being in Late Life: A Study of Daily Mechanisms

PI: Karen Fingerman, R01AG046460

Strong social networks (e.g., family, friends, and acquaintances) exert positive effects on older adults' emotional, cognitive, and physical health. Social engagement theory suggests that interacting with close ties and social groups leads to everyday activities that benefit health. Yet, gaping holes remain in understanding how social networks foster well-being via interactions and behaviors in daily life. Different social partners may serve complementary functions. This study addresses three important questions: 1) Do older adults who report a greater variety of social ties engage in more diverse social interactions throughout the day? 2) Do social partners serve distinct global (e.g., social support) and daily functions (e.g., conversations and physical activity throughout the day)? 3) Are these patterns of social networks and activities associated with daily and overall well-being? This study includes an initial interview assessing global properties of close ties and well-being and daily processes among older adults (N = 300). The study will use cutting edge modes of data collection throughout the day over four days: self-reports of social interactions collected via handheld computers, recorded conversations (via electronically activated recordings, EAR), and physical activity measured via actigraphs. This research will address older adults' social, emotional, cognitive, and physical experiences in the following three aims: Aim 1 will examine links between reports of the social network and social partners encountered in daily life. Individuals who report large social networks may interact with some of those social partners on a daily basis, but also report ties to social partners with whom they have infrequent contact. The study considers several modalities of contact (phone, in person, text). Aim 2 will assess how daily social interactions (incorporating relationship type, intimacy of tie, variety of interactions) are associated with daily cognitive, physical, and emotional experiences. A functionalist perspective suggests different social partners serve distinct functions. Aim 3 will examine associations between social networks, daily experiences, and daily well-being and global well-being. Interacting with a variety of social partners may be beneficial for daily mood, and physical symptoms. We also ask whether daily activities (e.g., conversations, physical activity) mediate associations between social networks and well-being. Across aims, we will consider correlates of social networks and daily activities: socioeconomic status (SES), gender, and age. Innovation and impact: Prior research has relied primarily on self-reports of close partners. This study will provide a novel investigation of how such reports are associated with daily social interactions, physical activity, and cognitive activity in everyday life. Researchers have documented the critical role of social ties on health for over three decades, but the proposed study will be the first to examine how social partners contribute to emotional, physical and cognitive experiences and to daily and global well-being. This study sets a stage for future longitudinal follow up of these participants and important information aimed at improving the social lives of older adults.

Education; Early Life Conditions; and Trends in Dementia

PI: Mark Hayward, R56AG057778

Dementia rates have fallen in a number of high-income countries over the past 25 years. Researchers have hypothesized that the decline reflects rising levels of educational attainment, a critical indicator of cognitive reserve which may account for individuals’ susceptibility to Alzheimer’s disease-related pathology. Technological and socioeconomic advances have disproportionately allowed well-educated persons to maximize the potential for a longer, healthier life due to healthier jobs and lifestyles, early adoption of health enhancing technologies, and improved control over disease risks (e.g., hypertension and diabetes)–all potential promoters of cognitive reserve. The ability of those with advanced education to garner health advantages is also accelerating, potentially widening the educational gradient in AD over time. Given the critical role of education in influencing AD and education’s centrality in the life course, this study evaluates the influence of education on cognitive health in the context of the life-course development and maintenance of cognitive reserve. The study is based on the Health and Retirement Study, 1998-2018, and represents the experiences of persons 65 years of age and older in the United States. The study is organized around two aims. A1: Because early-life conditions set in motion adult achievement processes and exposures-all AD risk factors, largely through the critical life experience of education, how do early-life conditions and education combine to influence dementia? We are interested in two basic issues. First, when early-life conditions are statistically controlled, what are the net consequences of education for dementia, and how have these associations changed over the 20-year period? Second, to the extent that both early-life conditions and education independently influence dementia, how do these factors combine to influence dementia across the period? A2. How sensitive are the effects of education, net of early life conditions, to the inclusion of major adult pathways also indicative of cognitive reserve? Has the sensitivity changed over time? Several major pathways will be examined in this study–socioeconomic achievement, health behaviors (smoking, heavy alcohol use and physical activity, and disease risk factors (e.g., CVD, depressive symptoms, and diabetes). Dramatic changes have occurred in all of these spheres that will inform our understanding the potentially changing pathways between education, adult AD-risk factors and cognitive health. At its core, this study is designed to inform our understanding of how education-a crucial AD risk factor-influences the cognitive health of older Americans. We use an approach in which education is embedded in the life course and assess the potentially complex ways life-course factors may combine to influence cognitive health; this provides an important window into the life-course origins of AD-related pathology. In addition, we recognize the enormous racial divide in AD risk, and we explicitly attend to the ways in which education may differentially benefit the cognitive health of blacks and whites in the context of the life course.

Evaluating Longitudinal Changes in the Human Structural Connectome in Relation to Cognitive Aging

PI: Elliot Tucker-Drob, R01AG054628

Progressive aging-related cognitive declines are associated with limitations in self-care and functional independence, deteriorating physical health, and impending dementia and mortality, even among the otherwise healthy. Identifying and understanding the neurodegenerative processes that underlie cognitive aging is key to developing interventions to prevent or ameliorate cognitive decline. Disconnection theories of aging specifically implicate weakening of structural brain connectivity as a key mechanism of cognitive decline, but until recently, diffusion MRI data and connectomic methods needed to rigorously test such theories have been lacking. To expedite understanding how aging-related changes in the human structural connectome relate to aging-related cognitive declines, we will apply the latest connectomic and multivariate data analysis methods to existing data from two highly unique datasets: (1) The UK Biobank, a cross-sectional sample of ~10,000 40-75 year old adults, who have undergone diffusion MRI scanning, have been measured with multiple cognitive tests, and have provided extensive sociodemographic and medical information; and (2) The Lothian Birth Cohort of 1936, a narrow-age cohort of older adults (baseline age = 73 years; N = 731) who have undergone diffusion MRI scanning, have been measured with multiple cognitive tests, and have provided extensive sociodemographic and medical information on each of three separate occasions, each separated by three years. Using recently developed graph-theoretic models, we will construct structural brain connectome networks for each participant's diffusion MRI data at each wave and extract indices reflective of network topology within several specific networks of interest (NOIs) identified ex ante. We will also identify topologically central hub regions that disproportionately govern efficiency within each individual's connectome network. We will apply cross-sectional and longitudinal structural equation models to examine aging-related transformations in network indices, examine concurrent and longitudinal coupling between network indices and cognitive abilities, and test predictors of levels and changes in network indices and cognitive abilities. This will allow us to contrast the predictive utility of the selected NOIs for cognitive aging and to identify specific features of network architecture involved in cognitive aging and mediate the effects of demographic, medical, and lifestyle risk factors for cognitive aging. We additionally implement machine- learning methods to estimate an upper bound of prediction of cognitive aging from network indices, and identify novel features of network topology as candidate mechanisms of cognitive decline. The availability of two uniquely large and well-characterized datasets will allow us to ensure that findings are rigorous and reproducible using within sample (holdout) and between sample cross-validation. For all aims, we will place considerable emphasis on testing for incremental validity of network indices relative to both conventional structural neuroanatomical measures and topologically naïve summary indices of network integrity.

Race/Ethnic Differences in Life Course Exposure to Death: Consequences for Health

PI: Debra Umberson, R01AG054624

Since blacks have long had a much lower life expectancy than whites, we argue that a dramatic and overlooked element of racial disadvantage and adversity is exposure to the death of family members. Latinos, on the other hand, have modestly higher life expectancy than whites and much higher life expectancy than blacks. This suggests that Latinos may have similar exposure to the death of family members as whites and much less exposure than blacks, which may be important in the relatively favorable health profile of Latinos in the United States. This project will shift thinking about racial/ethnic disparities and health by focusing on the death of family members throughout the life course as a fundamental cause of lifelong and accumulating disadvantage that affects long-term health and longevity. We hypothesize that the death of family members is more common and occurs earlier in the life course among blacks than Latinos and whites. In turn, death exposures shape the integrated biopsychosocial pathways that lead to poorer health and increased mortality risk, uniquely contributing to racial/ethnic disparities in physical health and mortality. We further hypothesize that these pathways will differ for men and women because of gender differences in family relationships, health outcomes, and potential mediating mechanisms such as health behaviors. This project relies on data from two NIH-sponsored national, longitudinal datasets (the Health & Retirement Study and the National Longitudinal Study of Adolescent to Adult Health) to estimate race/ethnic differences in specific (e.g., parents, children, siblings, spouses) and cumulative exposures to the death of family members across the life course, and how those exposures uniquely contribute to health from young adulthood to later life. Surprisingly little information is available concerning life course exposure to the death of multiple family members (and timing of deaths), and, in particular, racial/ethnic disparities in those exposures. This project will provide the first in-depth and population-based analysis of race/ethnic differences in exposure to death of multiple family members from childhood through adulthood and how those exposures shape racial/ethnic disparities in health and mortality risk. This project is designed to produce a knowledge base that will inform specific and evidence-driven intervention and policy guidelines to address racial/ethnic disparities in health that result from exposure to death of multiple family members. The research team includes leading scientists who are nationally recognized in population health research. The team is characterized by a complementary set of talents and experience that uniquely positions them to carry out this innovative project.

Dementia and Physical Disablement Processes among Aging Latinos

Co-I: Jacqueline L. Angel; PI: Sunshine Rote, University of Louisville, R03AG059107

The Latino population is rapidly aging and by 2050 will represent over 20% of the older adult population in the U.S. At the same time, the burden of dementia in the older Latino population is expected to increase from around 200,000 cases in 2000 to as many as 1.3 million cases in 2050, with many more suffering from milder degrees of cognitive impairment. A further stress on the Latino and specifically Mexican-origin population is high poverty rates. Close to 27% of older Mexican Americans in the U.S. live below the poverty line which is over double the rate for older adults in general. Disparities in dementia raise serious public health concerns; yet, there have been surprisingly few longitudinal studies on the role of dementia and cognitive impairment for physical disablement processes in the Mexican-origin population. Understanding how dementia shapes physical disablement pathways and identifying factors that slow down or speed up disablement will lead to a better understanding at which point geriatric public health intervention is most needed. We will employ a longitudinal cohort study of 3,050 older Mexican-origin individuals the 1993/94-2016/17 Hispanic Established Populations for the Epidemiologic Studies of the Elderly (H-EPESE). First, we will use nine waves of survey data to 1) describe the long-term patterns of dementia and cognitive impairment for a prospective cohort of older Mexican Americans. Growth Mixture Modeling (GMM) is used for this part of the analysis. Then, we will 2) estimate the role of dementia and cognitive impairment for changes in physical disablement processes over twenty years of study data. Finally, we will 3) assess differences in dementia-related physical disablement within the group by gender, socioeconomic status, and sociocultural factors. This research will lead to a better understanding of long-term health change for Mexican Americans in late life and an estimation of how many Mexican Americans with dementia need support in late life. Ultimately, our objective is to develop and evaluate a new empirical model to describe long-term patterns of dementia for physical disablement processes that can be replicated with other segments of the aging population to determine the extent of need for specialized long-term support services. 

Longitudinal Study of Mexican American Elderly Health

Co-I: Ronald Angel and Jacqueline L. Angel; PI: Kyriakos Markides, UTMB Galveston, R01AG010939

This renewal funded one more in-person follow-up of the Hispanic EPESE (Established Population for the Epidemiological Study of the Elderly) during 2015-16. The baseline was originally conducted in 1993-94 when a representative sample of 3050 Mexican Americans aged 65 and over residing in the Southwestern United States (Texas, New Mexico, Colorado, Arizona and California). At Wave 5 in 2004-05, a total of 1167 subjects then aged 75 and over were re-interview along with a new sample of 902 subjects also aged 75 and over drawn from the same region using similar procedures. The combined cohorts were followed up in 2007 (Wave 7, N=1542), 2010-11 (N=1078), and 2012-13 (Wave 8, N=744) when they were 82 and over. In 2010-11 we also interviewed 925 informants/caregivers of our subjects, two-thirds of whom were their adult children. We plan to re-interview the surviving subjects in 2015-16 and expect to have at least 500 aged 85 and over. We also plan to re-interview an informant/caregiver for each subject most of whom were interviewed in 2010-11. Thus in addition to following up our subjects to investigate predictors of mortality, disability, change in cognitive function, and institutionalizaion we plan to predict changes in caregiving arrangements over a five-year period. We are especially interested in how declines in the condition of the older subjects will be associated with changes in caregiving arrangements as well as the physical and psychological well-being of the caregiver. As in the 2010-11 contact we plan to contact the elderly subjects first and then their close family members we interviewed at that time. For deceased subjects we will obtain proxy interviews from close family members, most of whom are likely the caregivers we had interviewed. These reports will be confirmed with National Death Index (NDI) data as we have done throughout the study. Our study addresses a gap in the Mexican American family caregiver literature which has been mostly limited to small cross-sectional samples. As we have done in the past we will continue archiving our data with NACDA (National Archives of Computerized Data on Aging) and to encourage their use for doctoral dissertations, peer review publications and R03, R01, and other applications to NIA and other institutes by students and colleagues here at the University of Texas Medical Branch, the University of Texas at Austin, and at other institutions.

The Texas Resource Center on Minority Aging Research (RCMAR)

Co-I: Ronald Angel and Jacqueline L. Angel; PI: Kyriakos Markides, UTMB Galveston, P30AG059301

The overall purpose of the Texas RCMAR is to provide an infrastructure that facilitates the development of research on health and aging in minority populations with special focus on the Hispanic population in the United States as well as in Mexico. Special focus is given to mentoring researchers from underrepresented populations. The Texas RCMAR is based at the University of Texas Medical Branch with the University of Texas at Austin being the primary collaborating institution. To accomplish its objectives, the Texas RCMAR will have three cores: Administrative Core, Analysis Core, and Research Education Core. The Administrative Core will be directed by Kyriakos S. Markides, PhD, Gnitzinger Professor at the University of Texas Medical Branch (UTMB). As overall RCMAR Principal Investigator/Director, Dr. Markides will oversee and promote the activities of the other two cores. The Analysis core will be directed by Yong-Fang Kuo, PhD, Director of the UTMB Office of Biostatistics and Professor of Internal Medicine (Geriatrics) and of Preventive Medicine and Community Health. The Analysis Core will provide methodological and statistical support to promote the research and career development of minority aging investigators, especially those from underrepresented populations. The Core will interface with the Research Education Core to support Pilot research projects of mentored investigators and to participate in an annual two-day conference on minority aging to take place each September in conjunction with the annual International Conference on Aging in the Americas (ICAA) directed by Jacqueline Angel, PhD, University of Texas at Austin and member of our Research Education Core. The Research Education Core (REC) will be directed by Rebeca Wong, PhD, Kempner Professor and Director of UTMB's Pan American Health Organization Collaborating Center on Aging and Health. The REC will oversee funding of five pilot grants by minority investigators at UTMB, UT Austin and elsewhere. An effort will be made to recruit RCMAR scholars through the ICAA network of investigators conducting research on Hispanic aging in the United States and Mexico. Special emphasis will be given to providing training opportunities to Hispanic Servicing Institutions (e.g., University of Texas Pan American) and major universities in Texas with large numbers of minority/Hispanic students and faculty (e.g., Texas A&M University). 

Educational Attainment, Geography, and US Adult Mortality Risk

Co-I: Mark Hayward; PI: Jennifer Karas Montez, Syracuse University; R01AG055481

Educational attainment is one of the strongest social determinants of U.S. adult mortality risk. Studies to explain the education-mortality association have focused more on the individual-level “proximal” mechanisms (e.g., smoking) than identifying the contextual conditions that undergird the association. This major knowledge gap has consequences for science and public policy; it limits the discovery of explanations and interventions. The gap may reflect the dominant view in U.S. research that education is a personal resource. Accordingly, U.S. studies of the education-mortality association have emphasized agentic mechanisms: individuals with more education are thought to coalesce healthy lifestyles, seek out medical knowledge, avoid financial hardship, and so on. While agentic explanations are important, they ignore the fact that individuals are embedded in social and political contexts that influence the extent to which education matters for mortality. Despite numerous studies showing this to be the case in Europe, there has been scant research in the U.S. The goal of this study is to examine how and why the education-mortality association varies across U.S. states. Decisions made by governors and state legislatures affect employment, housing, transportation, social integration, healthy lifestyles, and numerous other social determinants of mortality. These state contexts have grown increasingly disparate through decades of deregulation and devolution. These trends may explain why, by the end of the 20th century, the range in life expectancy at age 50 across U.S. states exceeded the range across comparable high-income countries, and ½ of the variation in life expectancy across U.S. counties was attributable to the state within which they are located. This study addresses three questions: (1) How does the education-mortality association vary across states and over time?, (2) How does the variation in the education- mortality association across states and over time reflect state policies, resources, and opportunity structures?, and (3) What are the individual pathways through which state policies, resources, and opportunity structures shape the education-mortality association? The central hypothesis is that the association differs markedly across states, and that it is weakest in states with progressive economic policies, robust employment opportunities, and high social cohesion. The study will use data on adults aged 45-89 years in the restricted 1985-2011 National Health Interview Survey Linked Mortality File. Using discrete-time survival models, it will examine all-cause and cause-specific mortality. All analyses will be stratified by gender, age group, and time period. Analyses account for interstate migration and county-level mortality variation to better isolate the importance of state contexts. Expected outcomes of this study include: (a) estimates of the education-mortality association by state, and (b) insights into policies and strategies that states might employ to reduce mortality among their populations. The long-term goal is to reduce adult mortality, especially among vulnerable groups.

Network on Life Course Health Dynamics and Disparities in 21st Century America

MPI: Mark Hayward; Contact PI: James House, University of Michigan, R24AG045061

This funding formally created a research network to understand how and why the United States is increasingly falling behind virtually all comparably developed/wealthy nations, and even some developing countries, on major indicators of population health, despite the U.S. spending far more than any nation on health care and insurance. Limitations in data comparability across nations currently make comparative analysis of these issues difficult, and the proposed network and other scientists will be working to alleviate these limitations. However, understanding how and why portions of our population exhibit poor and/or worsening health is crucial to understanding America's paradoxical decline in health despite burgeoning spending for health care and insurance. Thus, the network will focus initial efforts on working across many existing sources of data to understand: 1) how and why the health of American women has been worsening since 1980 relative to both American men and women in other countries; 2) how and why socioeconomic disparities in health, especially by education, have persisted and even increased over the past three decades; and 3) how and why racial-ethnic disparities in health exist and persist, while also alleviating in some ways in recent decades. This work will later lead the network to: 1) systematic projection of past, present and especially future trends in U.S. population health and health disparities and the implications for expenditures on health care and insurance; and 2) comparative research to understand what factors have been most important in the worsening of America's population health relative to other comparably developed/wealthy nations. The network will bring together multidisciplinary teams of investigators from three institutions that have been leaders in research on social and biomedical determinants of population health and health disparities: Univ. of Michigan, Univ of Southern California/UCLA, and the Univ. of Texas at Austin. Key scientists from other institutions will be added to the network and/or will interact and collaborate with it via annual meetings and/or ongoing working groups. We seek to generate and disseminate new scientific analyses and findings, and to facilitate development of methods and data that can improve these analyses.

USC/UCLA Center on Biodemography and Population Health – Administrative Supplement

Co-I: Mark Hayward; PI: Eileen Crimmins, University of Southern California, P30AG017265

The aims of this supplement project are: (1) to examine change in dementia incidence, prevalence and dementia-free life expectancy in the U.S. a 16-year period (2) to determine how these are related to educational attainment, particularly the growing prevalence of college graduates in the population, and (3) to evaluate the importance of advanced education in garnering health advantages. Mortality information will be integrated with dementia information across the aims to better understand the demographic explanations for changes in dementia prevalence and dementia-free life expectancy. A crosscutting theme is to evaluate racial differences for each of the aims.

Educational and Early-Life Predictors of Mild Cognitive Impairment: New Evidence and Mediators and Moderators from High School & Beyond

Co-I: Chandra Muller; PI: Rob Warren, University of Minnesota, R01AG058719

Education is among the most important predictors of cognitive functioning and cognitive impairment (including MCI and AD/ADRD). However, because scientists do not know how or why education matters for these cognitive outcomes, it is difficult to design effective interventions. There is currently very little information about (a) the specific aspects of education that prevent or provide resilience to cognitive impairment and (b) the pathways through which those effects operate. A major reason for this lack of information about how or why education matters for these cognitive outcomes is that data on educational opportunities, environments, and attainments have mainly been gathered via retrospective reports. To know how and why education matters for cognitive functioning and impairment, the scientific community needs high quality prospective studies that follow young people through schools and throughout adulthood, measures key and modifiable aspects of education, and then assess cognitive functioning later in life. This project brings together an interdisciplinary team of leading neurologists, neuropsychologists, sociologists, education scientists, and survey methodologists who will design protocols to re-contact all ≈25,500 surviving members the High School & Beyond (HSB) cohort—a nationally representative random sample of Americans first interviewed in high school in 1980—and use the resulting data to conduct transformative analyses of the effects of education on cognitive function and risk for impairment at midlife. The project has five aims: (Aim 1) To estimate the effects of (a) adolescent cognitive and non-cognitive skills, (b) secondary school course taking and college field of study, and (c) other school structures and social environments on cognitive functioning and impairment at midlife; (Aim 2) To assess the degree to which racial/ethnic differences in those aspects of education explain racial/ethnic disparities in cognitive functioning and impairment; (Aim 3) To assess the degree to which the effects of education are mediated by educational attainment, economic strain, and the cognitive complexity of paid jobs at midlife; and (Aim 4) To assess the degree to which race/ethnicity and genetic risk factors moderate the effects of education on cognitive functioning and impairment. To gather the data required to pursue these Aims, the investigators will conduct an internet/phone survey and gather genetic material via a mail-back saliva kit. (Aim5) The resulting database and associated documentation and metadata will be made freely available to the research community to facilitate scholarship on the development of MCI, AD/ADRD, and cognitive decline.

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