These three risk factors may have the biggest impact on dementia cases

By Laura Williamson, American Heart Association News

Maria Bobrova/iStock, Getty Images
(Maria Bobrova/iStock, Getty Images)

Nearly half of all dementia cases in the U.S. may be linked to a dozen modifiable risk factors – most notably high blood pressure, obesity and physical inactivity, according to new research. The findings suggest a large portion of dementia cases could be prevented, especially among Black and Hispanic adults, who had the highest percentage of combined risk factors.

"There are things people can do that can raise or lower their individual risk" for dementia, said Mark Lee, a PhD candidate at the University of Minnesota in Minneapolis. He led the study presented Friday at the American Heart Association's Epidemiology and Prevention, Lifestyle and Cardiometabolic Health conference.

As the population ages, the number of dementia cases in the U.S. has been climbing. Currently about 5.8 million U.S. adults live with Alzheimer's disease and related dementias, according to the Centers for Disease Control and Prevention. That number is expected to hit 14 million by 2060, with Black and Hispanic adults seeing the largest increases. Among Hispanic adults, cases are expected to rise sevenfold, while cases among aging Black adults are expected to quadruple.

Those higher rates among Black and Hispanic people may be due to higher rates of heart disease and diabetes, which are linked to dementia risk. Social determinants of health – such as lower levels of education, higher rates of poverty and greater exposure to discrimination – also play a role.

Previous research identified 12 modifiable risk factors believed to be responsible for roughly 40% of dementia cases worldwide. A 2020 report by the Lancet Commission listed these as lower education level, hearing loss, traumatic brain injury, high blood pressure, excessive alcohol consumption, obesity, smoking, depression, social isolation, not getting the recommended amount of physical activity, diabetes and air pollution.

In the new study, researchers wanted to know if some risk factors had a greater influence than others on dementia rates – and how that differed among Black, Hispanic, Asian and white adults. They compiled data from the CDC's National Health and Nutrition Examination Survey and five other datasets.

Overall, 42.4% of dementia cases in the U.S. were attributable to the 12 factors, with three heart-related factors driving the bulk of that risk across races. High blood pressure, also known as hypertension, contributed to 6.7% of those cases; obesity to 7%; and physical inactivity to 6.7%.

The percentage of dementia cases attributable to those three risk factors was highest among Black adults. But the percentage of all 12 risk factors combined was highest among Hispanic people. Asian people had the lowest percentage of combined risk factors.

The results are considered preliminary until a full paper is published in a peer-reviewed journal.

The findings, Lee said, point to the need for better strategies to reduce heart-related risk factors, which would in turn reduce dementia risk population-wide.

This can, in part, be done through lifestyle changes, combined with medication as needed, said Priya Palta, an assistant professor of medical sciences and epidemiology at Columbia University Irving Medical Center in New York City.

"Maintaining a cognitively and physically active lifestyle and controlling risk factor levels pharmacologically, when necessary, throughout one's life course is critical for later-life brain health and is likely to impact many of the risk factors examined in this study," said Palta, who was not involved in the research.

Lee said the next step is to determine which interventions are most effective for reducing each of the 12 modifiable dementia risk factors. He also said a deeper investigation is needed into the social determinants of health underlying racial disparities, such as the disproportionately high rate of hypertension among Black adults.

"That's a really important direction we need to move to if we are serious about achieving equity in health interventions."

If you have questions or comments about this story, please email editor@heart.org.


American Heart Association News Stories

American Heart Association News covers heart disease, stroke and related health issues. Not all views expressed in American Heart Association News stories reflect the official position of the American Heart Association. Statements, conclusions, accuracy and reliability of studies published in American Heart Association scientific journals or presented at American Heart Association scientific meetings are solely those of the study authors and do not necessarily reflect the American Heart Association’s official guidance, policies or positions.

Copyright is owned or held by the American Heart Association, Inc., and all rights are reserved. Permission is granted, at no cost and without need for further request, for individuals, media outlets, and non-commercial education and awareness efforts to link to, quote, excerpt or reprint from these stories in any medium as long as no text is altered and proper attribution is made to American Heart Association News.

Other uses, including educational products or services sold for profit, must comply with the American Heart Association’s Copyright Permission Guidelines. See full terms of use. These stories may not be used to promote or endorse a commercial product or service.

HEALTH CARE DISCLAIMER: This site and its services do not constitute the practice of medical advice, diagnosis or treatment. Always talk to your health care provider for diagnosis and treatment, including your specific medical needs. If you have or suspect that you have a medical problem or condition, please contact a qualified health care professional immediately. If you are in the United States and experiencing a medical emergency, call 911 or call for emergency medical help immediately.