Is low blood pressure the best dementia defense?
Written by by danielle ray dray@paducahsun.com
Wednesday, January 27 2010 00:00
Aside from reducing stroke risk and improving overall health, lowering blood pressure could be the best known defense against dementia.
Currently, age is the greatest risk factor for dementia. But scientists have long noticed that some of the same triggers for heart disease — hypertension, obesity and diabetes — seem to increase the risk of dementia. For years, they thought these factors were linked to vascular dementia, memory loss associated with small strokes. Now hypertension — blood pressure readings of 140 over 90 or higher — seems to fuel the process of dementia.
The National Institutes of Health soon will begin enrolling thousands of hypertension sufferers in a major study to see if aggressive treatment — pushing blood pressure lower than currently recommended — better protects participants’ brains.
In a flurry of new research, scientists scanned people’s brains to show hypertension spurs a kind of scarring linked to later development of Alzheimer’s disease and other forms of dementia. Those scars, referred to as white matter lesions, can begin building in middle age, decades before memory problems will appear. White matter acts as the brain’s telephone network, a system of axons, or nerve fibers, that allow brain cells to communicate with one another. Even slightly elevated blood pressure can damage the tiny blood vessels that nourish white matter, interrupting those signals.
Dr. Patrick Withrow, vice president and chief medical officer of Western Baptist Hospital, said the scarring could be an early indicator of dementia.
“In middle age, it’s been found that the scarring that occurs in white matter due to hypertension looks the same as that in Alzheimer’s,” said Withrow. “Now we have to determine: Is blood pressure a partial problem in this? Is the lower the blood pressure, the better the individual’s chance of decreasing future risk? We don’t know yet.”
According to Withrow, a person’s blood pressure doesn’t have to be sky high to cause scarring; a systolic — top number — rate of 130 to 140 could potentially cause problems. The National Heart Lung and Blood Institute sets normal blood pressure levels at less than 120 systolic and less than 80 diastolic, though Withrow noted that one number does not fit all and a doctor’s assessment can best pinpoint a healthy blood pressure level.
Hypertension alone does not condemn someone to dementia; nearly one in three U.S. adults have high blood pressure compared to approximately one in eight people age 65 or older with dementia. But there are plenty of other reasons to lower blood pressure: Hypertension is a leading cause of heart attacks, strokes and kidney failure.
With dementia rising fast as the population ages, even a small effect from better blood pressure control could have a big public health impact, said Dr. William Thies of the Alzheimer’s Association. According to Dr. Lewis Kuller of the University of Pittsburgh, other preventative efforts, such as targeting the sticky amyloid plaques in Alzheimer’s patients’ brains, haven’t panned out so far, while hypertension control has little downside.
“Until I can tell you how to get rid of amyloid in your brain, take care of the blood pressure,” said Kuller.
The Associated Press contributed to this article.
Contact Danielle Ray, a Paducah Sun staff writer, at 270-575-8657.
SOURCE: www.paducahsun.com
