Study Continues Assessment of Cognition and Decline in Aging Latinos

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Researchers at University of California San Diego School of Medicine have received a $24.5 million grant from the National Institutes of Health (NIH)/National Institute on Aging (NIA) to continue the Study of Latinos-Investigation of Neurocognitive Aging (SOL-INCA), a 12-year assessment of cognitive and brain aging and impairment among aging Latinos.

The new SOL-INCA-AD grant continues a nationwide longitudinal study looking for telltale biomarkers of risk and resilience related to cognitive aging among Latinos of diverse heritages.

In the initial study, published earlier this year, researchers reported that higher midlife cardiovascular disease burden was significantly associated with increased rates of cognitive decline and prevalent Mild Cognitive Impairment (MCI) among Latinos. The cardiovascular burden varied by Latino heritage.

Latinos are exposed to early excess and chronic cardiovascular disease burden — particularly diabetes — which can contribute to cognitive decline and dementia onset.

SOL-INCA-AD extends the initial study to examine 10-year cognitive aging and dementia blood-based biomarker trajectories, including variations in cognitive decline, MCI and Alzheimer’s disease and related dementias (ADRD) among diverse Latinos.

Hector González, PhD, professor of neurosciences at UC San Diego School of Medicine and co-director of the Latino Core of the UC San Diego Shiley-Marcos Alzheimer's Disease Research Center, is co-principal investigator for the study.  

Charles DeCarli, MD, professor of neurology at UC Davis Health and director of the UC Davis Alzheimer’s Disease Research Center, is co-principal investigator.

Gonzalez said the funding is crucial to better understanding the aging brains of diverse Latinos who comprise nearly one-fifth of the United States’ population.

In 2020, Latinos represented 18.7 percent of the U.S. population and nearly 40 percent of the country’s two most populous states, California and Texas. By 2060, the U.S. Census projects a 391 percent increase in Latinos ages 65 years and older. The Centers for Disease Control and Prevention estimates that the largest increase in ADRD will affect aging Latinos, primarily due to excess cardiovascular disease burden. The new grant allows for upgrading data found in now-outdated studies.

“Studying diverse Latino populations is a neglected field in neuroscience and cognitive brain aging,” González said. “We really don’t know the neurobiology of diverse Latinos as we should. This new study enables us to examine genetic, cardio-metabolic and sociocultural contributions the aging brain.”

The researchers said that SOL-INCA-AD will gather data that could translate to real-world therapies, and potentially lessen the disease burden of dementia affecting Latinos.

“We can’t achieve health equity if we don’t have studies to develop the knowledge we need,” said DeCarli at UC Davis Health. 

Notably, SOL-INCA-AD will also examine how COVID-19 impacts the aging brain and cognitive health of Latinos. DeCarli said COVID-19 could negatively impact otherwise normal cognitive aging and increase dementia risk. 

“COVID-19 has disproportionately impacted Latinos in the U.S. and especially here in California,” González said. “Since SOL-INCA-AD is a longitudinal study, we’re in a unique position to understand the impacts of COVID-19 on cognitive aging in a large and understudied population. One potential outcome is using disease-modifying therapies, like new drugs just now coming onto the market, for people experiencing long-haul symptoms of COVID-19. My hope is that we can alter the trajectory for stability and improvement.”

SOL-INCA AD is also collaboration with Wayne State University in Detroit, MI. Wayne State University houses the study’s analytics and biostatistics core study, with Wassim Tarraf, PhD, associate professor of gerontology healthcare sciences, as study site principal investigator. 

Tarraf said the research provides an unprecedented opportunity to understand the complex pathways underlying cognitive aging and ADRD in diverse Hispanics and Latinos, beginning middle age. 

“This new funding allows us to delve into both the psychosocial and biological risk and protective factors for cognitive disease in a largely understudied population. It is an exciting opportunity to expand the science and to train and involve the next generation of scientists focused on working on equitable healthy aging.”