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Fending Off Dementia; Controlling Heart Risk in Midlife May Delay Alzheimer's, Study Finds

Posted on: Tuesday, 25 January 2005, 15:00 CST

Fending off dementia

Controlling heart risk in midlife may delay Alzheimer's, study finds

People who have unhealthy measures of heart health, such as high cholesterol or high blood pressure in their early 40s, are much more likely to develop dementia decades later, according to a new study.

The research adds to the growing concern that traditional risk factors for heart disease may also increase the odds of brain disease and mental decline. But unlike other studies that looked at individual risk factors later in life, the new study found danger early on from that cluster of conditions.

"If you can control these co-factors in midlife, you can reduce your (Alzheimer's) risk or maybe delay the onset of the disease because you'll have a healthier brain and healthier blood flow," said Diana Kerwin, a geriatrician and dementia specialist at the Medical College of Wisconsin in Wauwatosa.

Kerwin, who was not part of the study, said it's possible that by controlling traditional heart disease risk factors, a person who was predisposed to getting Alzheimer's might not develop symptoms until age 85, instead of age 75.

The study, published today in Neurology, looked at about 9,000 people who were part of the Kaiser Permanente Medical Care Program of Northern California. Researchers looked back to see how many of them had high blood pressure, high cholesterol or diabetes or smoked when they were ages 40 to 44.

They then assessed how those risk factors were associated with developing dementia 27 years later.

As it turned out, each one of the conditions increased the risk of developing dementia by between 20% and 40%, and combinations increased the odds considerably more.

High blood pressure increased the risk 24%; smoking, 26%; high cholesterol, 42%; and diabetes, 46%.

Those who had any two risk factors had a 69% increase in risk; three risk factors, 231%; and four risk factors, 237%.

"This is the first time it (heart risk factors) has been looked at this early in the life span," said lead author Rachel Whitmer.

The strength of the study is that it used a large, diverse group of men and women who had equal access to health care and who were followed for an average of 27 years, said Whitmer, a research scientist with Kaiser Permanente. The study was funded by the National Institutes of Health.

"It really emphasizes that you can't start too early in working on maintaining your brain," said Sam Gandy, a spokesman for the Alzheimer's Association and director of the Farber Institute for Neuroscience at Thomas Jefferson University. "It's possible that Alzheimer's is really a disease of midlife that doesn't manifest itself until later in life."

Gandy said the study also points to a change in thinking about the cause of Alzheimer's. For many years, doctors thought there were two distinct types of dementia: vascular dementia, which was caused by blockages in the blood vessels of the brain, and Alzheimer's, which was caused by the buildup of the protein amyloid-beta around brain cells.

"The distinction between the two is getting blurrier and blurrier," he said.

Blockages blur

For instance, the accumulation of amyloid-beta inside blood vessels now is considered a main cause of blockages in those vessels, he said.

It still is not known what plays a bigger role in developing Alzheimer's, genetics or lifestyle, but the new study shows there are things a person can do to substantially reduce risk, said Marilyn Albert, an Alzheimer's Association spokesman and professor of neurology at Johns Hopkins University School of Medicine.

"We know there are risk factors that we haven't yet discovered," Albert said. "These are risk factors that we can actually do something about."

The one drawback of the study is that it is a retrospective analysis not a randomized clinical trial, Albert said.

However, such a trial would be nearly impossible to do today in that it would be unethical to allow a group of people with risk factors such as high blood pressure or high cholesterol to go untreated, she said.

Albert said the study bolsters similar findings of how individual risk factors can increase the risk of dementia.

"The fact that we keep getting the same answers gives us increasing security that we have the right answers," she said.

Risk factors

The study found that certain factors increased the risk of developing dementia 27 years later. The factors and how much they increased the risk were:

-- High blood pressure, 24%

-- Smoking, 26%

-- High cholesterol, 42%

-- Diabetes, 46%

Copyright 2005, Journal Sentinel Inc. All rights reserved. (Note: This notice does not apply to those news items already copyrighted and received through wire services or other media.)

Source: Milwaukee Journal Sentinel

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