Welcome Dr. Ruijia Chen, whose Research Examines Cognitive Aging
Welcome, Dr. Ruijia Chen
This year, Dr. Ruijia Chen joined UCLA’s Department of Community Health Sciences in the Fielding School of Public Health as an assistant professor and also as a CCPR faculty affiliate. As a social epidemiologist, Chen investigates how social factors across the life course contribute to risks and disparities in cognitive function and dementia in later life.
“The experiences and conditions we’re exposed to throughout our lives can have a long-lasting influence on our health as we age,” Chen explains. Social stressors rarely arrive one at a time, so her research considers how multiple social conditions cluster and jointly contribute to disparities in cognitive aging.
Temporal Dimensions of Exposures and Cognitive Aging
The temporal dimensions of exposure are crucial to Chen’s work. In one study published in Social Science and Medicine, she demonstrated that individuals who experienced high levels of stressors during childhood had meaningfully lower cognitive function decades later, even when they did not experience high levels of stress in adulthood. Chen’s more recent work, published this July in Alzheimer’s & Dementia, found that social network characteristics were associated with cognitive function among adults aged 90 and older, echoing patterns observed in younger populations. The study found no evidence that social network characteristics predicted decline in cognitive function over time, nor did it find an association with mortality in this group.
Rethinking Social Connection and Cognitive Aging
Social connection is another cornerstone of Chen’s research agenda. With support from the Alzheimer’s Association, she examines how social isolation and dementia vary across countries and over time.
Her research also addresses a fundamental methodological challenge of how to measure social isolation. “Even within the Health and Retirement Study, there are so many ways that have been used to define social isolation,” she says. To address this, Chen is leading a study to examine whether these seemingly arbitrary measurement choices actually alter the substantive conclusions researchers draw. Furthermore, Chen and her team integrate self-reported measures with information from wearable devices to capture dimensions of social connection that may be difficult to measure through self-report alone.
Chen also aims to strengthen causal evidence on social isolation and dementia. As a Co-Investigator with the TIME-AD program (a large initiative that aims to triangulate innovative methods to end Alzheimer’s Disease), Chen and colleagues apply modern causal inference approaches to strengthen evidence on social isolation as a potentially modifiable risk factor for dementia. This approach addresses challenges such as time-varying social exposures and the possibility of reverse causation as cognitive impairment develops.
Bridging social epidemiology with policy
Perhaps Chen’s most ambitious research project is just beginning: bridging social epidemiology, population health surveillance, and social policy to reduce risk and inequities in dementia-related outcomes. Supported by an NIA K99/R00 award, this project targets a challenge in public health infrastructure: the lack of a reliable, ongoing surveillance system to track dementia prevalence at the state level. Dementia is largely underdiagnosed, and diagnoses recorded in administrative data do not capture all individuals living with the condition. Thus, this research links population-based survey data with administrative data to improve the identification of dementia to produce more reliable dementia prevalence estimates across states and over time. Once that foundation is established, Chen will investigate how specific social policies affect those rates, beginning with SNAP benefits and pension or income-support policy for older adults within the US and across countries.
At UCLA, Chen will continue investigating how social conditions across the life course affect cognitive function and dementia risk decades later, and how social policy can respond. She looks forward to collaborating with UCLA’s multidisciplinary researchers and students pursuing social epidemiology and aging research.
Chen earned her doctorate in social and behavioral sciences from the Harvard T.H. Chan School of Public Health and completed postdoctoral training in epidemiology at Boston University School of Public Health and UCSF School of Medicine. She also holds a master’s degree in social policy from the University of Pennsylvania.
Selected Publications
