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It can begin with the occasional missed bill payment. An inability to remember names. Telling the same story repeatedly. There may be personality changes or mood swings. Confusion. Over time, it's as if the person who once was slowly disappears.

Dementia. As the population ages, a growing number of families face this debilitating condition, which can be both emotionally and financially exhausting, and require near-constant supervision from spouses or adult children. It can be tough on any family, but in the United States, Black and Hispanic communities are hardest hit.

"We don't exactly know why," said Jason Resendez, executive director for the UsAgainstAlzheimer's Center for Brain Health Equity in Washington, D.C. "More and more evidence is pointing to a mix of factors that are health-related, such as disparities in diabetes and heart disease. But there are also social and economic factors, such as education, social isolation, smoking, low income and other inequalities."

While dementia risk in the United States has been relatively stable over the past two decades, racial disparities have remained high, according to research published last year in . Other data suggest Black adults, from age 50 onward, are two to three times more likely than their white peers to be ; Latinos are at 1.5 times .

Research shows many of the risk factors can be reduced. In fact, efforts to do so are meeting with some success – but less so for people of color. For example, a in JAMA Neurology found cholesterol-lowering drugs could reduce dementia risk by 23%, but they were less effective for Black and Latino adults than for their white peers.

Up to 40% of all cases of dementia could be reduced by lowering 12 risk factors, according to a . These include high blood pressure, obesity, smoking, diabetes, physical inactivity, depression, hearing loss, less education, air pollution, social isolation, excessive alcohol consumption and traumatic brain injury.

Nearly all of these factors "are intertwined with social inequities," Resendez said. "We are not all born with the same opportunity for brain health."

Black and Hispanic adults, for example, are more likely to have blood pressure levels uncontrolled than white adults, said Dr. Deborah Levine, an associate professor of internal medicine and director of the Cognitive Health Services Research program at the University of Michigan. Black adults also tend to have more severe high blood pressure and develop it at an earlier age than white adults.

Levine led a showing Black adults' cumulative high blood pressure rates might explain their faster cognitive declines compared to white adults.

High blood pressure also significantly increases the risk for stroke – a risk that is higher among Black and Hispanic adults than it is for their white peers, she said. And stroke doubles the risk for dementia. Levine led another study that showed following a stroke than it does in people who haven't had one.

The troubling statistics on these health disparities are not explained by genetics, said Chandra Jackson, a research investigator with the National Institute of Environmental Health Sciences, part of the National Institutes of Health. "These disparities are the manifestation of historical and contemporary forms of structural racism."

Years of discrimination in housing, education, employment, earnings, benefits, credit, media and criminal justice have all contributed to making people of color more vulnerable to the conditions that foster poor health, she said.

"The places where people live, learn, work and play affect dementia risk," said Jackson, who also is an adjunct investigator with the National Institute of Minority Health and Health Disparities at the NIH. Researchers call these the "social determinants of health."

A last year by the Urban Institute and UsAgainstAlzheimer's highlighted the role social inequities play. It compared counties with the highest rate of Alzheimer's disease – the most common form of dementia – among Black and Latino adults to those with the lowest rates. Counties with the highest rate of Alzheimer's also had the highest percentage of families living in poverty, fewer opportunities for exercise and people with less education and health insurance.

The stress of living with racism likely also plays a role, said Lynn Rosenberg, a professor of epidemiology at Boston University and epidemiologist at its Slone Epidemiology Center. She is a principal investigator for the Black Women's Health Study. Her team found experiencing the highest levels of racism in their daily lives measured lower on tests of cognitive function than those who experienced less racism.

Other everyday stress increases dementia risk.

Eliminating the disparities in dementia and other health risks will require tackling structural racism on a societal level, Jackson said. It also means creating communities that promote healthier living through greater access to economic stability, healthy foods, opportunities for physical activity and better social supports for families and caregivers.

But research shows there also are steps individuals can take to improve brain health: stop smoking, eat a healthier diet, stay active, lose weight and maintain good blood pressure, cholesterol and blood sugar levels.

These are steps people should take long before they reach their senior years, Resendez said. "We need to target people in their 30s and 40s. Their actions today affect their brain health 20 years from now."

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