A person’s place of residence directly influences key risk factors for developing dementia, underscoring the need for tailored national prevention strategies. This conclusion was reached by researchers from the University of Southern California following an extensive analysis of data from over 214,000 older adults across 14 countries and regions. The findings were reported by Science Daily on July 13.
The study examined data collected between 2009 and 2023 from the United States, European countries, China, India, Brazil, and other nations. It revealed that the prevalence of major risk factors—such as low education levels, smoking, and hypertension—varies significantly depending on geographic location.
For instance, low educational attainment affects 85.6% of older adults in China, compared to just 12% in the United States. Meanwhile, a high body mass index was observed in 44.9% of Americans, versus 13.3% of individuals in India. The researchers also noted that certain risks often cluster globally: cardiovascular conditions (like high cholesterol and hypertension) tend to occur together, as do harmful habits such as smoking and alcohol consumption.
Emma Nichols, a research associate at the Center for Economic and Social Research within the Schaeffer Institute at the University of Southern California and lead author of the study, remarked: “I was less surprised by the differences and more by some of the similarities, particularly how these risks are distributed across varying settings. This has important implications for designing prevention and intervention strategies, because certain patterns turn out to be more consistent across locations than we might have anticipated.”
During the study, the team examined 12 modifiable risk factors, including hearing loss, depression, physical inactivity, and social isolation. According to the authors, these insights will aid governments in developing healthcare programs that precisely address the needs of specific population groups. For example, expanding measures to combat diabetes could simultaneously help tackle issues related to hypertension.
Nichols emphasized that the study’s findings carry an optimistic message, as the risk of cognitive decline in old age is not predetermined. She noted that individuals can influence this risk throughout their lives by changing their habits. In the future, the researchers plan to broaden the geographic scope of their work, incorporating data from Kenya and Egypt, as well as exploring the impact of sleep quality on dementia development.
On July 8, the journal Neurology highlighted a connection between declining income and early-onset dementia. According to the study, early dementia leads to a loss of work productivity that may become apparent many years before diagnosis. The researchers clarified that income differences between dementia patients and a control group were noticeable as early as 15 years before the condition was formally identified.
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