Dementia rising across Latino populations, multidecade study finds

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A new study led by researchers at Washington University School of Medicine in St. Louis and Newcastle University in the U.K. finds that the share of adults living with dementia rose substantially across several Latin American and Caribbean sites over the past two decades. The research provides the first direct evidence that some parts of Latin America are moving in the opposite direction of dropping dementia rates in the U.S. and other wealthy nations. The study appeared in JAMA Neurology.

A two-decade study led by WashU Medicine neurologist Jorge Llibre-Guerra, MD, provides the first direct evidence based on door-to-door surveys of older adults that dementia is rising across several Latin American and Caribbean sites, even as rates hold steady or fall in wealthier nations. Image credit: Getty Images

The researchers analyzed data from 16,950 adults ages 65 and older in Cuba, the Dominican Republic, Mexico, Peru and Puerto Rico, collected first in the early 2000s and then about 20 years later. Over that time, dementia prevalence in Mexico, Peru and Puerto Rico rose significantly, from roughly one in 10 older adults to nearly one in six. Dementia rates held stable in Cuba and the Dominican Republic.

“For decades, almost everything we knew about whether dementia was becoming more or less common came from wealthy countries outside of Latin America,” said first author Jorge Llibre-Guerra, MD, an assistant professor of neurology at WashU Medicine. “We simply didn’t have that picture for Latinos, even as the region’s population is aging faster than almost anywhere else. What we found is sobering: The gains made elsewhere in the world are not reaching everyone, and it underscores how much the burden of dementia is shaped by the conditions people live in.”

Concerning regional trends
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In many high-income countries, including the U.S., dementia prevalence — the share of older adults living with the neurodegenerative condition — has been holding steady or even falling in recent decades, likely thanks to improvements in access to education and healthier lifestyles, leading to better blood pressure control and heart and metabolic health.

To address the near-absence of evidence on dementia trends in Latin America, Llibre-Guerra; senior author Matthew Prina, PhD, a professor of aging and epidemiology at Newcastle University; and their colleagues drew on the 10/66 Dementia Research Group, a multinational effort established in the early 2000s to build population-based dementia data from low- and middle-income countries, including five sites in Latin America and the Caribbean. At each site, fieldworkers went door to door, surveying every consenting adult age 65 or older. The home-visit approach allows researchers to reach people who might never visit a health clinic or specialist and are therefore often excluded from data collected from hospitals or physician offices.

The survey was conducted in 2003–2006 and again in 2016–2020 to capture long-term trends in dementia prevalence. Dementia was diagnosed with a validated combination of cognitive testing, a clinical interview and an interview with a person close to the participant, designed to identify dementia fairly across different cultures and education levels.

The overall prevalence of dementia across the five sites climbed from 10.6% to 16.9% over two decades. When examining individual sites, the researchers found dementia prevalence rose significantly in Mexico (from 9.6% to 14.5%), Peru (from 7.6% to 11.7%) and Puerto Rico (from 10.7% to 15.7%), even after accounting for the aging of the population between the time points.

Dementia rates in the other two study sites, Cuba and Dominican Republic, remained stable. The authors suggest this may be because those populations have not undergone the same rapid surge in obesity, physical inactivity and unmanaged metabolic disease that has characterized other parts of the region over the past two decades. That stability gives reason for optimism, Llibre-Guerra said, because it suggests that if modifiable risk factors are kept under control, rising dementia prevalence is not inevitable.

Extrapolated nationally, the dementia rates in the study at the most recent time point translate to roughly 1.2 million people living with dementia in Mexico, 416,800 in Peru, 133,200 in Cuba, 100,400 in Puerto Rico and 111,200 in the Dominican Republic. These figures substantially exceed earlier estimates, which were based on statistical models rather than counting cases directly, and they indicate that dementia in Latin America and the Caribbean “has been systematically underestimated,” Llibre-Guerra said.

Mexico and Puerto Rico
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In Mexico and Puerto Rico, increases in dementia persisted even after the researchers accounted for differences in education, health behavior and risk factors such as diabetes and obesity — suggesting that deeper social and structural issues, such as poverty and lack of access to healthcare or other underexplored risk factors, are shaping dementia risk in these countries.

“The findings suggest that the declining trends in dementia observed in some high-income countries may not be replicated globally,” said co-author Ana Luisa Sosa, MD, PhD, a psychiatric epidemiologist at the National Institute of Neurology and Neurosurgery in Mexico City. “In fact, the data indicate that dementia prevalence may be rising in certain settings, highlighting important global inequalities and public health challenges.”, she added.

The authors say the findings point to a need for stronger surveillance, investment in dementia care, and population-level prevention strategies across the countries they studied — as well as more research to determine if the same trends exist in other, larger Latin American countries such as Brazil, Argentina and Chile.

“Many of the risk factors we suspect are driving these increases are things we know how to address,” Llibre-Guerra said. “Staying physically active, managing blood pressure and blood sugar, not smoking, seeking care promptly when symptoms arise and staying socially connected are all evidence-based ways to reduce risk. And at the policy level, our findings argue urgently for investing in dementia surveillance, prevention programs and care infrastructure. If we act now, there’s a real opportunity to change the trajectory for the next generation of older adults in the region.”

Citation
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The study Trends in dementia prevalence across five Latin American and Caribbean sites: two decades of rising prevalence was published in JAMA Neurology. July 13, 2026. DOI:10.1001/jamaneurol.2026.2305. Authors: Llibre-Guerra JJ, Wu YT, Acosta I, Soria C, Sosa AL, Acosta D, Jiménez-Velázquez IZ, Guerra M, Salas A, Lu R, Llibre-Rodriguez JJ, Prina M

Funding
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The 10/66 Dementia Research Group’s research has been supported by the Wellcome Trust Health Consequences of Population Change Programme (GR066133 for the prevalence phase in Cuba and Brazil; GR080002 for the incidence phase in Peru, Mexico, Argentina, Cuba, Dominican Republic, Venezuela, and China), the World Health Organization (India, Dominican Republic, and China), the Alzheimer’s Association (grants IIRG-04-1286; 24HPE-1287320; ALZSI-25-1464205), the Puerto Rico State Legislature (Puerto Rico), FONACIT/CDCH/UCV (Venezuela), the European Union (RC-2013-ADG 340755), Davos Alzheimer’s Collaborative (DAC-GC-02230426.01), and National Institutes of Health (K01AG073526). These funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. The corresponding author had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Conflict of Interest Disclosures
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Dr. Llibre-Guerra’s reported receiving grants from the Alzheimer’s Association, the National Institutes of Health, the Michael J. Fox Foundation, the Foundation for Barnes-Jewish Hospital, and the Davos Alzheimer’s Collaborative outside the submitted work. Dr. Prina reported receiving grants from the Alzheimer’s Association during the conduct of the study and grants from the National Institute for Health and Care Research outside the submitted work. All other authors declare no competing interests directly relevant to this work.