07/13/2011 04:52 pm ET | Updated Sep 12, 2011

Surprising Factors That Could Up Alzheimer's Risk: Study

There is no way to prevent aging, which is the single biggest risk factor for developing Alzheimer's disease. But a surprising new study suggests that engaging in healthy behaviors, like taking care of your vision and ensuring proper denture fit, could help lower risk for Alzheimer's and dementia.

Relying on some 7,000 responses to the Canadian Study of Health and Aging, researchers set out to see if health problems widely believed to be risk factors for Alzheimer's and dementia -- like heart disease and diabetes -- indeed predicted development of the disease. They also looked at health factors not typically linked with brain decline, such as eyesight quality, bladder control problems, dental issues and denture fit. They hoped to discern what role -- if any -- they might play.

When considered individually, the researchers found that each health problem was indeed linked to an increased risk of bad outcomes, albeit an extremely small one at just over 3 percent. When people responded they had 8 of the problems, that risk increased by 30 percent, prompting the authors to conclude that cumulatively, issues that "take a toll" on general health might also be associated with increased risk for dementia and Alzheimer's.

"The single risk factors that we looked at tended to be less important than overall general health," said researcher Dr. Kenneth Rockwood, a professor of medicine and Alzheimer research at Dalhousie University in Canada.

"Leading an active, healthy life when you're younger is more likely to lead to better brain health when you're older," he added.

But in recent years, there has been debate within the scientific community about the role modifiable factors might play in risk for Alzheimer's and dementia. A U.S.-based panel recently found insufficient high-quality scientific evidence linking lifestyle issues with risk.

Which means, researchers caution, that current studies should be taken as part of a still-growing, non-definitive body of literature.

In the meantime, Rockwood encouraged people concerned about developing Alzheimer's and dementia to take a more pragmatic approach.

"People should engage in a healthy lifestyle now, and that includes all of the specific factors that can add up -- particularly exercise," he said. "You don't have to wait 20 years for all of the data to come in."

Steven Ferris, director of the Alzheimer's Disease Center at NYU, said the Neurology study opened up interesting questions, both about the role modifiable behaviors might play in the diseases development and about how genetic predispositions and vulnerabilities might make certain people more susceptible than others.

"It's certainly hard to imagine direct linkages between these risk factors and the disease," said Ferris, who was not associated with the study. "But this adds to the growing evidence that Alzheimer's development is a very long, many-decades process. If that's the case, then these other factors could absolutely be a part of general susceptibility."