Silent Strokes Increase Risk Of Alzheimer's
Alzheimer's disease and other forms of dementia may be more than twice as likely to occur in people who have had "silent strokes" - a stroke that has no apparent symptoms.
This finding, by Danish researchers and published in the The New England Journal of Medicine, suggests that in later life, there is an increased risk of dementia and a more severe and rapid decline in memory loss, from the brain-damage caused by silent strokes.
In their study of 1,015 elderly patients, Monique M.B. Breteler, MD, PhD and her colleagues, found that those who had silent strokes at the beginning of their study, as measured on an MRI, and who also showed no signs of dementia, were more than twice as likely to demonstrate symptoms of mental decline over the course of the four-year study.
Those with a history of silent stroke at the beginning of the study also had a faster rate of decline in their thinking.
"I was surprised, when we did the study, to see how large a proportion of elderly people who do have small infarcts in their brain that were never clinically recognized," lead researcher Breteler commented. "One in five people over the age of 60 had at least one silent brain infarct. I was also impressed by the size of the risk increase, which suggests that we should advocate stronger control of vascular risk factors in an attempt to help prevent dementia."
"It's been observed for years that people who had a stroke and later develop Alzheimer's typically don't do as well with their Alzheimers, and have a faster rate of decline," says Bill Thies, PhD, vice president of medical and scientific affairs for the Alzheimer's Foundation. "This study is high-quality confirmation of data we've seen before that suggests the development of dementia is, in many cases, perhaps a combination of effects" -
- partly from the brain changes that are associated with Alzheimer's and
- partly from those that result from problems with circulation and blood vessels.
"Take care of your blood vessels (vascular system) if you want to retain as much function as possible in your later years," Thies emphasises. That means following the same "heart-smart" regimen of:-
- as you normally would do to prevent heart disease, cancer, diabetes, and other health threats.
- eating a healthy diet,
- getting regular exercise,
- not smoking,
- and controlling blood pressure, cholesterol, weight, and blood-sugar
This strategy may be especially important if you consider that these silent strokes occur nearly 15 times more often than classic strokes - yet many people are completely unaware they have had them. According to data presented to the American Stroke Association, silent strokes afflict about 4% of the U.S. population at some point in their lives.
Although rare before age 30, the chance of having silent strokes doubles every 10 years, say researchers. By the time people reach their 70s, one in three has experienced at least one silent stroke per year - usually showing no obvious initial symptoms and detectable only through a brain scan.
But the injury accumulates over time, leading to symptoms of dementia such as memory and thinking impairments, as well as difficulty in walking.