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ADD TIME ON GOOGLEby Kathleen FeltonOpen follow modalPersonalized Content

Kathleen FeltonFollow this author to personalize your feed and get instant alerts.

Lucy Lambriex—Getty Imagesby Kathleen FeltonOpen follow modalPersonalized Content

Dementia is a serious global health concern. It affects more than 57 million people worldwide, according to the World Health Organization, and is the seventh leading cause of death. In the U.S., 42% of Americans are at risk of developing dementia after age 55, a 2025 study found.

The condition “dramatically affects people's quality of life,” says Dr. Josef Coresh, founding director of the Optimal Aging Institute at NYU Langone and a senior investigator on the new study. “We’ve also come to appreciate that a lot of dementia is preventable, and a lot of the prevention potential relates to vascular risk factors.”

Health and behavior across the entire lifespan contribute to a person’s risk of eventually developing dementia. But the new findings suggest there are still opportunities in midlife to prevent or delay its onset, says Coresh. In your 40s, 50s, and 60s, “you have the potential to continue to reduce the risk” of cognitive decline and possibly gain more years living without dementia.

Some groups of people had an even lower risk of developing dementia. Regardless of their number of risk factors, female participants without dementia lived longer than male participants, and white participants tended to spend more years without dementia than Black participants.

The research does not prove that these three risk factors caused dementia—only that there is an association between not having them and living longer without the condition. Risk factor measurement was also only performed once, at the study’s onset, and doesn’t account for other lifestyle habits or behaviors during those 20 or so years. ”We don't capture worsening over time, or smoking cessation, for example,” wrote Weiss.

In July 2026, the World Health Organization released updated guidelines on modifiable dementia risk factors, which included not smoking, managing diabetes and hypertension, and avoiding other health conditions and behaviors.

“We’ve really found—over the last decade, even—an accumulation of many, many risk factors for dementia,” says Dr. Jeffrey Kaye, a professor of neurology and biomedical engineering at Oregon Health & Science University and director of the Layton Aging and Alzheimer’s Disease Center (who wasn't involved in the new study).

Other potential ways to lower dementia risk include keeping your brain active, being social, and doing regular physical activity, as well as cutting back on alcohol, eating a balanced diet, maintaining a healthy weight and cholesterol levels, managing hearing loss, and reducing exposure to air pollution. The WHO guidelines estimated that by addressing all of these modifiable risk factors, 45% of dementia cases could be avoided.

Some dementia cases can’t be prevented, however. Age, for example, is the single greatest risk factor: About one in 13 people from ages 65 to 84 have Alzheimer’s disease. Among people 85 and older, that rises to about one in three. A person’s genes, race, and gender also influence their odds of having dementia.

A challenge for clinicians, says Kaye, is that studies like this look at an average, “and unfortunately, nobody’s average.” His hope is that in the future, experts will be able to move towards more individualized care, taking into account factors like a person’s genetics, health practices, and socioeconomic status to help mitigate a patient’s risk of cognitive decline in a sustained way.

But this latest research underscores the thinking that behavior and overall health impact your brain with age, and dementia isn’t an inevitable part of getting older. “Trying to mitigate the risks of having certain conditions or health practices is really important,” says Kaye.

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