A major study published on 13 July has found that the factors influencing dementia risk differ markedly from one country to another. Rather than supporting blanket global approaches, the results point to the value of evidence that respects distinct national contexts, education systems, healthcare realities and cultural patterns.
Researchers examined harmonised survey data from more than 214,000 older adults collected between 2009 and 2023 across 14 countries and regions, including the United States, England, Ireland, Northern Ireland, four regions of Europe, Korea, Mexico, China, Malaysia, Brazil and India. The peer-reviewed analysis, which appeared in The Lancet Healthy Longevity and was presented at the Alzheimer's Association International Conference in London, focused on 12 modifiable risk factors previously identified by the Lancet Commission.
The prevalence of these risks varied substantially by location. Low education affected 85.6 percent of older adults in China but only 12 percent in the United States. High body mass index, by contrast, was recorded in 44.9 percent of older adults in the United States yet only 13.3 percent in India. Such figures illustrate how deeply national circumstances shape exposure to known risks.
Consistent patterns amid variation
Despite these differences, certain risk factors clustered together in similar ways across locations. Cardiovascular risks such as high cholesterol and hypertension often appeared alongside one another, as did behavioural risks like smoking and drinking. These recurring groupings suggest that some underlying mechanisms transcend borders even as the dominant individual threats do not.
Emma Nichols, lead author and research scientist at the USC Schaeffer Institute for Public Policy and Government Service, said:
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 and interventions, because some things are more consistent across places than we might expect.
She added:
