Global Study Reveals How Location Influences Dementia Risk Factors

New Delhi, India Jul 13, 2026 ALN: A new study led by researchers at the University of Southern California (USC) involving more than 214,000 older adults from 14 countries indicates that preventing dementia may require distinct strategies tailored to different regions. The research reveals that many significant modifiable dementia risk factors, such as low education, high blood pressure, and smoking, vary considerably across countries. This challenges the notion of a universal approach to dementia prevention.

Understanding Global Variations in Dementia Risk

The findings were presented at the Alzheimer's Association International Conference 2026 in London and published in The Lancet y Longevity. Historically, most research on dementia prevention has focused on high-income countries, including the United States and Western Europe. To broaden the understanding of dementia risk, USC researchers collaborated with colleagues from Brown University and Johns Hopkins University to analyze data from both high-income and low- to middle-income countries.

Dementia, a collective term for a range of cognitive impairments, affects millions of people worldwide. The most common form of dementia is Alzheimer's disease, which accounts for a significant proportion of dementia cases. With the global population aging, the prevalence of dementia is expected to rise dramatically, making effective prevention strategies more critical than ever. The research conducted by USC and its partners sheds light on how different environmental, social, and economic factors can influence the risk of developing dementia.

The study uncovered significant differences in risk factors. For instance, low education levels affected 85.6% of older adults in China, compared to only 12.0% in the United States. Conversely, high body mass index (BMI) was found in 44.9% of Americans, while only 13.3% of individuals in India exhibited this condition. These disparities highlight the need for tailored approaches to dementia prevention that take into account the unique socio-economic contexts of different countries.

Common Patterns Amidst Differences

Despite the varying individual risk factors, the study identified notable similarities in how these factors cluster together globally. Cardiovascular issues such as high cholesterol and hypertension frequently appeared in conjunction, while lifestyle behaviors like smoking and alcohol consumption also tended to co-occur. This suggests that while the prevalence of specific risk factors may differ across regions, the underlying patterns of how these factors interact may be more universal.

Emma Nichols, the lead author and a research scientist at the USC Schaeffer Institute for Public Policy & Government Service, expressed surprise at the consistent patterns observed across different settings. "I was less surprised by the differences and more surprised by some of the similarities, particularly in the ways these risks are patterned across settings," Nichols stated. This insight holds significant implications for designing effective prevention strategies that can be adapted to local contexts while still addressing common risk clusters.

Data Collection and Analysis

The research team utilized harmonized survey data collected between 2009 and 2023 through the Gateway to Global Aging Data project. This dataset integrated information from long-standing aging studies across 14 locations, including the United States, England, Ireland, Northern Ireland, various European regions, Korea, Mexico, China, Malaysia, Brazil, and India. The diverse geographic and cultural backgrounds of the participants contribute to a more comprehensive understanding of dementia risk factors.

Researchers examined 12 modifiable dementia risk factors identified by the Lancet Commission, including hearing loss, depression, physical inactivity, and social isolation. They assessed the prevalence of each risk factor, its variation by age, gender, and education level, and the frequency of multiple risk factors occurring together in individuals. This multifaceted approach allows for a nuanced analysis of how different factors interrelate and contribute to dementia risk.

Implications for Dementia Prevention

The findings from this study could assist governments and organizations in developing prevention programs that are more aligned with the specific needs of their populations. For instance, a diabetes management program could be expanded to address related cardiometabolic risks like high cholesterol and hypertension, allowing for a more comprehensive approach to care that integrates dementia prevention into broader initiatives. This could lead to more effective resource allocation and improved outcomes for older adults.

Furthermore, the study emphasizes the importance of public education and awareness campaigns that target modifiable risk factors. By informing communities about the risks associated with low education, high blood pressure, and uny lifestyle choices, stakeholders can foster environments that promote ier behaviors. This proactive approach is vital in mitigating the impact of dementia on individuals and society as a whole.

Nichols emphasized the encouraging message for individuals: "Risk for these late-life outcomes isn't predetermined. These are risk factors you experience over the life course, and you can have an impact on changing your own risk while also recognizing the ways broader societal factors shape that risk, too." This perspective highlights the role of individual agency in outcomes, as well as the importance of addressing systemic issues that contribute to disparities.

Future studies are expected to explore additional modifiable risk factors, including poor sleep, while expanding research to more countries as comparable datasets become available. This ongoing research is crucial for developing a more comprehensive understanding of dementia risk and prevention across diverse populations. As the global landscape continues to evolve, so too must our strategies for addressing the growing challenge of dementia.

About the Study

The study was led by Emma Nichols from the USC Schaeffer Institute's Center for Economic and Social Research. Additional authors include senior author Jinkook Lee, Michael Markot, Drystan Phillips, and Jenny Wilkens from the Gateway to Global Aging Data team; co-first author Zachary Kunicki from the Warren Alpert Medical School of Brown University; and Alden Gross from the Johns Hopkins Bloomberg School of Public. The research received support from the National Institutes of (grant R01AG030153). This collaboration among prestigious institutions underscores the importance of interdisciplinary approaches in tackling complex public issues like dementia.