Dementia prevention risks vary sharply by country, study finds
A USC-led analysis of older adults in 14 countries found major national differences in modifiable dementia risk factors.
By Tom Brennan · Health & Medicine Correspondent
3 min read
A USC-led study of more than 214,000 older adults found that the most common preventable dementia risk factors differ widely by country and region. The findings suggest that public health programs aimed at reducing dementia risk may need to be tailored to local populations rather than built around a single global plan, according to the University of Southern California.
The research was published in The Lancet Healthy Longevity and presented at the Alzheimer's Association International Conference 2026 in London, USC said. The study examined data from 14 countries and regions and compared how often major modifiable dementia risk factors appeared in older adults.
Risk patterns differed across countries
USC said researchers found large differences in several risk factors that can be changed or addressed over a person's life, including low education, high blood pressure and smoking. Low education was reported among 85.6% of older adults in China, compared with 12.0% in the United States, according to the study summary from USC.
Body mass index showed a different pattern, USC said. High BMI was found in 44.9% of older adults in the United States and 13.3% of those in India, according to the researchers.
The team also found that some risk factors tended to group together in similar ways across countries, USC said. Cardiovascular conditions such as high cholesterol and hypertension often appeared together, while smoking and drinking also commonly clustered as related behaviors.
Emma Nichols, lead author and a research scientist at the Center for Economic and Social Research at the USC Schaeffer Institute for Public Policy & Government Service, said the shared patterns were notable because they could guide prevention programs. Nichols said she was more surprised by the similarities in how risks were patterned across settings than by the differences.
Data came from aging studies worldwide
The researchers used harmonized survey data collected from 2009 to 2023 through the Gateway to Global Aging Data project, according to USC. The combined dataset included long-running aging studies from the United States, England, Ireland, Northern Ireland, four regions of Europe, Korea, Mexico, China, Malaysia, Brazil and India.
USC said the team assessed 12 modifiable dementia risk factors identified by the Lancet Commission on dementia. Those factors included hearing loss, depression, physical inactivity and social isolation, in addition to cardiometabolic and behavioral risks.
The researchers measured how common each risk factor was and how prevalence differed by age, gender and education level, according to USC. They also studied how often multiple risks appeared in the same person.
Findings could shape prevention programs
The findings could help governments and health organizations design dementia prevention efforts around the risks most common in their own populations, USC said. For example, the researchers said a diabetes management program could also address related cardiometabolic risks, including high cholesterol and hypertension.
Nichols said the results also point to the potential for people to change some of their risk over time, while recognizing that broader social conditions also influence exposure to risk factors. USC said future research may include additional modifiable risks, such as poor sleep, and expand to more countries as comparable data become available.
Data collection is already underway in Kenya and Egypt, according to USC. The study was led by Nichols, with additional authors from USC's Gateway to Global Aging Data team, Brown University's Warren Alpert Medical School and the Johns Hopkins Bloomberg School of Public Health. USC said the work was supported by the National Institutes of Health.
This story draws on original reporting from ScienceDaily.