A huge global study of more than 214,000 older adults across 14 countries reveals that the factors most strongly linked to dementia differ widely depending on where you live. The findings challenge the idea that a one-size-fits-all prevention approach can work worldwide.
The research
Researchers led by Emma Nichols at the University of Southern California (USC) analyzed harmonized data from aging studies in the United States, England, Ireland, Northern Ireland, four European regions, Korea, Mexico, China, Malaysia, Brazil, and India. The data were collected between 2009 and 2023 through the Gateway to Global Aging Data project.
The team examined 12 modifiable risk factors identified by the Lancet Commission on dementia, including low education, hearing loss, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, high alcohol intake, head injury, air pollution, and social isolation. They measured how common each risk factor was and how often they clustered together.
Results showed stark differences. For example, low education affected 85.6% of older adults in China but only 12.0% in the United States. High body mass index (obesity) was found in 44.9% of Americans versus just 13.3% in India. However, despite these striking contrasts, certain risk factors tended to co-occur in similar patterns worldwide. Cardiovascular risks like high cholesterol and hypertension frequently clustered together, as did behaviors like smoking and drinking.
Nichols noted, “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. That has real implications for how we design prevention strategies.” The research was presented at the Alzheimer's Association International Conference 2026 and published in The Lancet Healthy Longevity.
Why it matters
This study underscores that dementia risk isn’t predetermined — many factors are modifiable. But the strategies that work in one country may miss the mark in another. For instance, in the U.S., tackling obesity and hypertension might be top priorities, while in China, improving access to education could have a bigger impact. Understanding your personal risk profile, which is shaped by where you live, can help you focus on the changes that matter most for your brain health.
What you can do
You can take control of several key risk factors starting today. Stay physically active, keep your blood pressure and cholesterol in check, avoid smoking, limit alcohol, maintain a healthy weight, and stay socially connected. If you have hearing loss, consider using hearing aids — untreated hearing loss is one of the largest modifiable risk factors for dementia. And keep learning throughout life; education builds cognitive reserve.
Source: ScienceDaily Mind & Brain
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