Older Adults Taking Heart Disease, Diabetes Meds Have Slower Rates of Cognitive Decline

Questions remain about whether the drugs offer benefit or other factors are involved

Liz Szabo,

AARP

Comments

En español

Published July 28, 2025

Getty Images

Older adults who took medications for high blood pressure, high cholesterol and diabetes had slower rates of cognitive decline over a nine-year period than others, according to an observational study of 4,651 older adults. The median age of participants was 77.

“Persons who were on two or three medication classes performed as if they were cognitively three years younger,” says Roshni Biswas, a research scientist at the Rush Alzheimer’s Disease Center, who presented the study July 27 at the Alzheimer’s Association International Conference in Toronto. “The cognitive change in someone who was 80 and on three medication classes was similar to the cognitive change in someone who was 77 and on none of the studied medication classes.”

The results don’t offer concrete advice. Although an observational study can show whether two things are related, it is not able to prove cause and effect, says Mitchell S. V. Elkind, M.D., chief science officer for brain health and stroke at the American Heart Association.

Treating modifiable risk factors

Doctors have long known that high blood pressure, high LDL cholesterol (the bad type of cholesterol) and diabetes increase the risk of dementia. A recent clinical trial from China found that taking medication to lower blood pressure for as little as four years can reduce the risk of dementia by 15 percent.

Another trial from the United States found that study participants randomly assigned to take medication to aggressively lower their blood pressure reduced their risk of mild cognitive impairment or probable dementia by 11 percent more than participants who reduced their blood pressure by a smaller amount.

The Lancet Commission last year concluded that about 45 percent of all cases of dementia are potentially preventable if people address 14 modifiable risk factors throughout their lives.

Those risk factors also include vision loss, hearing loss, smoking, obesity, depression, physical inactivity, excessive alcohol consumption, traumatic brain injury, air pollution, lack of education and social isolation.

High blood pressure, diabetes and high cholesterol damage blood vessels, including vessels that lead to the brain or are in the brain itself, says Glenn Herrington, a cardiology clinical pharmacist practitioner at Novant Health Heart & Vascular Institute in Wilmington, North Carolina.

The complex relationship between wealth and health

Most studies that examine the role of medication in slowing cognitive decline focus on a single drug. A growing number of older adults suffer from all three conditions, especially if they have obesity. That’s led researchers to wonder whether taking multiple classes of medications offers additional benefits compared with taking just one.

The new study doesn’t answer that question directly, Elkind says.

That’s because the researchers were limited to observing what happened to people who take multiple medications and compared them to people who take fewer medications or no drugs at all.

The study included participants with and without high cholesterol, diabetes and hypertension, Biswas says. All the participants were cognitively healthy when the studies began, with no dementia symptoms, and all had access to health care. That means the study’s findings may not apply to people without access to health care, Biswas says.

To prove that taking multiple classes of medications slows the rate of cognitive decline, researchers would need to randomly assign people to either take the medications or do something else, such as take a placebo, Herrington says.

Those trials tend to be very expensive. Randomized controlled trials often require government funding, especially if the medications being tested are available as cheaper generics, given that drug companies have little incentive to test drugs that they don’t sell themselves.

In the new study, Elkind says it’s possible that the people who took multiple medications were different from others in ways that influenced their brain health.

Although Biswas and her colleagues factored in participants’ age, sex and education, they did not include the participants’ incomes.x

It’s possible that the people who took medications for three medical conditions may have had better access to health care than those who took fewer medications or no drugs at all, Elkind says. People with more money also tend to have more reliable transportation, which makes it easier to go to the doctor.

Research shows that people with more money have lower risks of dementia than people with less money and fewer privileges.

How the study was performed

This research was based on findings from five ongoing, long-term studies of aging and dementia run by the Rush Alzheimer’s Disease Center: the Religious Orders Study, the Rush Memory and Aging Project, the Minority Aging Research Study, the African American Core Study and the Latino Core Study. Those studies were funded by the National Institute on Aging, part of the National Institutes of Health.

Researchers measured participants’ cognitive ability every year using 18 neuropsychological tests, Biswas says. Doctors also updated participants’ medication lists once a year. About 75 percent of participants were women, and 28 percent were Black. Dementia rates in the United States are highest among Black and Hispanic adults.

The team also examined autopsy results in 1,896 of the participants who died during the study period, according to the brief version of the study presented at the conference.

Among autopsied participants, the odds of having atherosclerosis and arteriosclerosis in the brain were about 50 percent lower among those taking three medications than among participants who took none of the studied medications. In atherosclerosis, the arteries are lined with plaques of fatty material on their inner walls. Arteriosclerosis is a thickening and hardening of the artery walls.

People who took multiple medications were also less likely to have the plaques and tangles in their brain that characterize Alzheimer’s disease.

Even participants who took one or two medications had a slower cognitive decline and less cardiovascular and brain damage than those who took no medications, although the advantage was not as large as seen in those taking three medications, according to the study abstract.

Elkind says the study findings are difficult to interpret. Although the participants taking medications had presumably been diagnosed with diabetes, high cholesterol or hypertension, the abstract doesn’t reveal the severity of those illnesses, he says, noting that people taking three medications may be much sicker than those taking fewer drugs.

“It could be that people who are on medications are on them because they have more severe disease,” Elkind says. “It doesn’t necessarily mean that the medications are even controlling the condition that they have.”

%{postComment}%