He feels lucky, Harold Edwards said, that his memory loss and other mental symptoms are easier to handle than those of his father and two sisters.

Then, during a short, otherwise lucid conversation, he said it three more times, using mostly the same words:

"I feel real lucky; I'd rather be like this than like the rest of my family was."

At 59, Edwards of Fuquay-Varina said Tuesday that he "gets along good" but has the loss of concentration and short-term memory typical of vascular dementia. His father died at age 57 of what was then diagnosed as "hardening of the arteries." Two sisters also died after suffering forms of dementia.

More than a million people in the United States have vascular dementia -- a term for a group of diseases related to reduced blood flow in the brain -- either by itself or along with other conditions including Alzheimer's disease. Former U.S. Sen. Jesse Helms is one of them, his wife, Dot, recently told The News & Observer.

Cases of vascular dementia are projected to triple by midcentury as the baby boomers age.

In many cases, symptoms closely resemble those of Alzheimer's. Edwards' wife said he has both.

"Alzheimer's is more closely related to a buildup of plaques and tangles in the brain; in vascular dementia it's more a blockage in the brain," said Dr. Murali Doraiswamy, a dementia researcher at Duke University Medical Center.

The disease is getting more research, said Dr. Heidi Roth, assistant professor of neurology at UNC-Chapel Hill.

"The exciting thing is that there may be different types of treatment and prevention for vascular dementia by treating risk factors early," Roth said.

The most common cause is hypertension, Doraiswamy said. Other treatable risk factors include high cholesterol and diabetes. Stroke and atherosclerosis, a buildup of plaque in an artery, can also be factors.

Harold Edwards takes recommended medications for cholesterol. He is also on Namenda, one of several Alzheimer's drugs that are being tested for use with vascular-dementia patients but have not been approved for such use by the Food and Drug Administration.

"We are looking at a number of experimental drugs," Doraiswamy said.

Another area of research that's getting more attention is the overlap between Alzheimer's and vascular dementia, said Roth at UNC-CH.

"One-third of people with Alzheimer's disease may have a vascular component, and one-third of people with vascular dementia may have Alzheimer's disease," she said.

Traits that distinguish the disease from Alzheimer's include a rapid onset of symptoms and a "stepwise" decline in which patients remain stable for a while, then noticeably decline again.

"In Alzheimer's disease, typically you have memory loss as the initial presenting feature," Doraiswamy said. "That may be the case in vascular dementia, but it depends on where the stroke occurs; you might have a speech problem first."

Virginia Homovec, 81, of Raleigh noticed several years ago that her husband, Joseph, had trouble concentrating. He kept forgetting to turn out lights and could not concentrate on his cherished books or even watch television.

After an initial diagnosis of Alzheimer's, Mr. Homovec, a World War II veteran who had suffered from diabetes and a stroke, was diagnosed with vascular dementia.

"He used to be a ham radio operator," Mrs. Homovec said. "You have call letters and numbers and you are talking to people all over the world. That means your mind has to be good. When he couldn't retain the letters and numbers, that bothered him."

Last year, Mr. Homovec went into an assisted living facility in Raleigh, then to a skilled nursing facility and finally to Rex Hospital, where he died in December at age 83.

Harold Edwards said his memory problems surfaced when he suffered a stroke while working as a Mecklenburg County sheriff's deputy in 2004. He had another stroke last year and has difficulty doing things that the "manly man" once handled easily, said his wife, Charlotte.

"I don't really have a husband per se; I am more of a caretaker," said Mrs. Edwards, 52, who works for a home builder. "Used to be, he could read instructions and could put something together in short order. Now he cries and says, 'I can't do it.'"

As Mr. Edwards' memory problems have increased, his wife said, the couple have adjusted. But his problems put a strain on daily arrangements and their relations with some friends.

"People I worked with say, 'I don't know how you deal with it,'" Mrs. Edwards said. "I say, 'How do you not deal with it?' That's my life and how it goes day by day."