In an era of personalization of medicine and prevention, it becomes difficult to talk in general terms about actions to limit the risks of the onset of cognitive impairment and Alzheimer’s disease. In fact, each country should have a sort of “specific” approach to reducing risks, also based on the actual weight of the risk factors on the area in question.
This is reiterated by research coordinated by experts from the University of Southern California led by Emma Nichols, presented at the Alzheimer’s Association International Conference 2026 in London and published in The Lancet Healthy Longevity. The survey examined 14 countries and found that the main preventable causes of dementia vary greatly from one country to another.
Analyze large populations
The research team used harmonized survey data, collected between 2009 and 2023 through the Gateway to Global Aging Data project. The dataset combined information from long-term aging studies conducted in 14 countries, including the United States, England, Ireland, Northern Ireland, four European regions, Korea, Mexico, China, Malaysia, Brazil and India. (Jinkook Lee of the Center for Economic and Social Research at the USC Schaeffer Institute is the principal investigator of the Gateway to Global Aging Data project and the Longitudinal Aging Study in India.)
The researchers looked at 12 modifiable risk factors for dementia, identified by the Lancet Commission on Dementia, including hearing loss, depression, physical inactivity and social isolation. They measured the frequency of each risk factor, its differences by age, sex and education level, and the frequency with which multiple risk factors occurred simultaneously in the same individual.
Thus the weight of risk factors changes
The study shows that many of the most important modifiable risk factors for dementia, including low education, hypertension and smoking, vary considerably between countries. Indeed, it should not be forgotten that the major contributions to existing research on the prevention of dementia come from high-income countries, such as the USA and Western Europe.
To determine whether these findings are actually applicable more broadly, the experts along with colleagues from Brown University and Johns Hopkins University examined data from both high-income and low- and middle-income countries. The results revealed substantial differences, along with some unexpected similarities. For example, low educational attainment affected 85.6% of older adults in China, but only 12.0% of those in the United States. Excess body weight defined by high BMI was found in 44.9% of Americans compared to only 13.3% of people in India.
Although individual risk factors differed from country to country, many of them occurred together in similar combinations globally. Cardiovascular conditions such as high cholesterol and hypertension often occurred together, while behaviors such as smoking and alcohol consumption tended to occur in clusters.
It requires a targeted approach
According to the researchers, the findings could help governments and health organizations create prevention programs better suited to the needs of their populations. For example, a diabetes management program could also be extended to address related cardiometabolic risks, such as high cholesterol and hypertension, allowing several interconnected health issues to be addressed simultaneously. Nichols emphasized that the findings also convey a message intended for individuals:
“The risk of these pathologies in old age is not predetermined. These are risk factors that manifest themselves throughout life, and everyone can influence their own risk, while recognizing that broader social factors also have an impact”
comments the expert.
