Common risk factors for dementia vary between rich, poor countries, study finds
Research indicates that modifiable dementia risk factors differ significantly between high-income and low- and middle-income countries.
Common risk factors for dementia vary between rich, poor countries, study finds
A global study of more than 214,000 older adults suggests that dementia prevention strategies must be tailored to specific regions, as the most common modifiable risk factors vary significantly between high-income and low- and middle-income countries. The research, presented at the Alzheimer's Association International Conference in London and published in The Lancet Healthy Longevity, indicates that a universal approach to prevention is unlikely to be effective.
The study was led by researchers at the University of Southern California (USC) in collaboration with Brown University and Johns Hopkins University. The team sought to determine if patterns observed in wealthy nations, such as the United States and Western European countries, hold true in less wealthy settings.
The data, collected between 2009 and 2023 through the Gateway to Global Aging Data project, combined information from long-running aging studies in 14 countries and regions. These locations included the United States, Brazil, China, England, India, Ireland, Korea, Malaysia, Mexico, Northern Ireland, and four regions of Europe. Jinkook Lee of the USC Schaeffer Institute served as the principal investigator for both the Gateway to Global Aging Data project and the Longitudinal Aging Study in India.
Researchers analyzed 12 modifiable risk factors identified by the Lancet Commission on dementia, which include social isolation, physical inactivity, depression, and hearing loss. They examined how these factors varied by gender, age, and education level, and how often they occurred together in a single person.
The disparities between nations were stark. Low education affected 85.6% of older adults in China, compared to only 12.0% of those in the United States. Conversely, high body mass index (BMI) was found in 44.9% of Americans, while only 13.3% of people in India shared this risk factor.
Despite these differences, the study uncovered unexpected similarities in how risk factors cluster. More than 50% of individuals across all countries and regions had at least two risk factors. Certain groupings appeared consistently worldwide: cardiovascular conditions like hypertension and high cholesterol frequently occurred together, and behavioral risks such as drinking and smoking tended to cluster.
"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,"
Emma Nichols, research scientist with the Center for Economic and Social Research at the USC Schaeffer Institute for Public Policy & Government Service, via sciencedaily.com
Nichols stated that these shared patterns have implications for the design of interventions because some risks are more consistent across different locations than previously expected.
The findings could allow governments and health organizations to create programs that better match the needs of their specific populations. For example, the researchers suggested that a program designed to manage diabetes could be expanded to address the wider cluster of related cardiometabolic risks, such as hypertension and high cholesterol, simultaneously.
For individuals, Nichols noted that the results provide an encouraging message, stating that risk for late-life outcomes is not predetermined. She said that while societal factors shape risk, people can impact their own risk over the course of their lives.
The research was supported by the National Institutes of Health under grant R01AG030153. The author list includes Nichols, senior author Jinkook Lee, Michael Markot, Drystan Phillips, and Jenny Wilkens from the Gateway to Global Aging Data team, co-first author Zachary Kunicki of the Warren Alpert Medical School of Brown University, and Alden Gross of the Johns Hopkins Bloomberg School of Public Health.
Future research will look to include additional modifiable risk factors, such as poor sleep. The study also aims to expand into more countries as comparable datasets become available, with data collection already underway in Egypt and Kenya.
