Completed Studies

Enhancing data quality for cross-national harmonization: Assessment of cognitive function in the CHARLS HCAP by language, literacy, and visual impairment. 

The Harmonized Cognitive Assessment Protocol (HCAP) of the China Health and Retirement Longitudinal Study (CHARLS) is an innovation that aims to measure older adults’ cognitive function in China using items that are harmonized with those used in HCAPs in other countries around the world. China is a linguistically diverse country with a high prevalence of both illiteracy and uncorrected visual impairment amongst its older population. In this study, we decontaminate measurement differences in the CHARLS HCAP due to spoken language or dialect, written literacy, and visual ability from true underlying levels of cognitive function, with an ultimate public health goal to enhance the quality of the CHARLS HCAP data to facilitate valid cross-national comparisons of older adults’ cognitive function using data from the NIA-funded international HCAP network.

Funding: National Institute on Aging, 3R01AG070953-03S1 (PIs: Kobayashi and Gross)

Accounting for pre-baseline selective survival in cross-national studies of the exposome in Alzheimer’s disease and related dementias: a novel bias assessment tool. 

Cross-nationally harmonized data provide a major opportunity to evaluate the consistency of exposome-ADRD associations across diverse populations and contexts, but a key methodological limitation is selective survival that happens in target populations prior to the study baseline. This study addresses this bias by innovatively quantifying plausible magnitudes of pre-baseline selection bias in exposome-ADRD research using the HCAP network data and developing a user-friendly web-based app that will allow other researchers to understand the impacts of this type of selection bias in their own research on the exposome in relation to ADRD. This study aims to provide research resources that will help to elucidate the role of the exposome in ADRD outcomes and disparities from a global perspective.

Funding: National Institute on Aging, 3R01AG070953-03S2 (PIs: Kobayashi and Gross)

Risk and Resilience Factors in Memory Aging Among Older Cancer Survivors: A Cross Country Comparison of the US and England. 

This project leverages longitudinal pre- and post-cancer diagnosis data from two nationally representative cohorts, the US Health and Retirement Study (HRS) and the English Longitudinal Study of Ageing (ELSA), to investigate long-term memory trajectories of middle-aged and older cancer survivors.  The specific aims are to: (1) identify and compare memory trajectories of cancer survivors in the HRS and ELSA, overall and by age and sex; (2) identify and compare individual, neighborhood, and macro-level socioeconomic inequalities in memory aging of cancer survivors in the HRS and ELSA; and, (3) identify the roles of modifiable risk and resilience factors (hypertension, diabetes, obesity, depression, physical activity, social support) across countries, as these may be intervention targets to promote healthy memory aging among older cancer survivors (R00 phase). This research will unite the fields of cancer survivorship and ADRD research by using a cross-national, population-based approach to identify high-risk groups of older cancer survivors for accelerated memory decline, as well as identify modifiable risk factors as intervention targets.

Funding:  National Institute on Aging, 1K99AG076532-01A1 (PI: Westrick)

The COVID-19 Coping Study: A longitudinal mixed-methods study of older adults’ mental health and well-being during the COVID-19 pandemic in the United States. 

We conducted a longitudinal study of over 4,000 men and women aged 55 and over in the United States to evaluate month-by-month changes in mental health and well-being, particularly in relation to social and economic changes as a result of the COVID-19 pandemic. We are tracking changes in employment, living circumstances, self-isolation and other necessary COVID-19 control measures, access to parks and green space, and coping strategies employed by older adults. Ultimately, we aim for results to inform equitable public health interventions and clinical practices to harness positive coping strategies, foster social support, and encourage meaningful daily activities among older populations during times of stress and trauma. Learn more about the COVID-19 Coping Study on our study website or download our data at ICPSR.

Education and cancer-related cognitive decline during aging. 

Education predicts better cognitive function in older adults generally and substantially reduces dementia risk, but is largely unexplored in the US general population of middle-aged and older cancer survivors. With innovative use of data that were collected prior to cancer diagnosis in order to rule out reverse causation and a follow- up period of up to 16 years after cancer diagnosis, this research will illuminate the risk modifying roles of education and other cognitive reserve markers in cancer-related cognitive decline at the general population level. We are using data from the nationally representative US Health and Retirement Study and linked Medicare data from 1998-2016. We use segmented linear mixed models to estimate memory change prior to and after a new cancer diagnosis and treatment across levels of cognitive reserve markers, with age-matched cancer-free adults as a comparison group. This research is a first step towards achieving our long-term goal of understanding and improving cognitive aging outcomes in the growing population of older cancer survivors.

Funding:  National Cancer Institute, R03CA241841 (PI: Kobayashi)