Keeping your heart healthy may play a role in keeping your memory sharp later in life, according to research published Wednesday in the journal Neurology.

Other factors, including not smoking, past high scores on cognitive tests and the presence of a particular gene variant, were also linked to better memory for people in their 90s, the study found.

“What’s good for the heart seems to be good for the brain and seems to be very important in avoiding Alzheimer’s disease,” the study’s lead author, Beth Snitz, an associate professor of neurology at the University of Pittsburgh, said.

Alzheimer’s disease is the most common form of dementia, affecting over 5 million Americans, according to the Alzheimer’s Association. The chances of getting Alzheimer’s increases with age. Symptoms include memory loss, change in behavior and decline in reasoning.

Many studies on Alzheimer’s aim to understand what factors contribute to the disease. But the new study focused on what protects people from it.

“Sometimes the answers to what predicts resilience and health in aging are not simply the opposite of what predicts disease or not simply the absence of what predicts disease,” Snitz said.

In the study, 100 people who initially showed no signs of Alzheimer’s were tracked for 12 to 14 years, with the average person ending the study in their 90s. At the beginning of the study, the participants took cognitive tests, as well as provided information about their health history.

Then, throughout the study period, they had PET imaging scans of their brains every two years and a clinical evaluation that included cognitive tests once a year. PET scans can reveal one of the hallmarks of Alzheimer’s: a buildup of a type of protein in the brain called amyloid plaques.

The study found that participants who had healthy blood vessels were less likely to develop plaques. In particular, the researchers looked at what’s called pulse pressure, a measurement related to blood pressure. It’s often used as a way to gauge cardiovascular health.

Dr. Reisa Sperling, director of the Center for Alzheimer Research and Treatment at Brigham and Women’s Hospital in Boston, stressed the importance of cardiovascular health when it comes to brain health.

“It’s probably the case that it’s a one-two hit between Alzheimer’s pathology and vascular pathology that contribute to cognitive decline in this age range,” said Sperling, who was not involved with the new research.

Another factor found in participants who didn’t go on to develop amyloid plaques was the presence of a variant of a gene called APOE. While only 10 patients in the study had this gene variant, none went on to develop plaques.

The link between APOE gene variations and Alzheimer’s risk has long been studied; one variant of the gene is associated with an increased risk of Alzheimer’s, while another has been linked to a lower risk. The new research, however, was one of the first studies to confirm this link in an advanced aging population.

“It puts the nail in the coffin,” in terms of the link between the gene variants and Alzheimer’s risk, Snitz said.

She added that a better understanding of the role that genes play in Alzheimer’s could help researchers develop better treatments. “We can’t decide what genes were inherited, but hopefully they can be a sort of a mechanistic clue as to how we can develop new drugs,” she said.

The study also found that, among patients who did develop amyloid plaques, certain factors appeared to play a role in whether they maintained a sharp memory. Those factors included being a nonsmoker and scoring the normal range on the cognitive test given at the study’s onset.

The findings underscore the importance of healthy behaviors for brain health.

“I think this is really encouraging that some of the things like staying active in work and other types of stimulating activities might be protective even into the 90s,” Sperling said.

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