A major international study of more than 214,000 older adults shows that modifiable dementia risk factors differ significantly by country. The research, led by the University of Southern California, indicates that prevention strategies must be tailored to local conditions rather than applied uniformly worldwide.
The findings were presented at the Alzheimer's Association International Conference 2026 in London and published in The Lancet Healthy Longevity. Researchers analyzed data collected between 2009 and 2023 from 14 countries and regions, including the United States, England, China, India, and Brazil.
Low education affected 85.6 percent of older adults in China but only 12.0 percent in the United States. High body mass index was found in 44.9 percent of Americans compared with 13.3 percent of people in India. Cardiovascular conditions such as high cholesterol and hypertension often clustered together, as did behaviors like smoking and drinking.
"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," said lead author Emma Nichols of the USC Schaeffer Institute. The study examined 12 modifiable risk factors identified by the Lancet Commission on Dementia.
Researchers said the results could help governments design more effective prevention programs that address multiple connected health issues at once. Data collection is already underway in additional countries including Kenya and Egypt.
