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National Institutes of Health to study high blood pressure's link to dementia

If the cardiologist's warnings don't scare you, consider this: Controlling blood pressure just might be the best protection yet known against dementia.

In a flurry of new research, scientists scanned people's brains to show hypertension fuels a kind of scarring linked to later development of Alzheimer's disease and other dementia. Those scars can start building up in middle age, decades before memory problems will appear.

The evidence is such that the National Institutes of Health soon will begin enrolling thousands of hypertension sufferers in a major study to see if aggressive treatment better protects their brains.

Age is the biggest risk factor for Alzheimer's disease and other forms of dementia that affect about one in eight people 65 or older. Scientists have long noticed that some of the same triggers for heart disease — high blood pressure, obesity, diabetes — seem to increase the risk of dementia, too. But for years, they thought that link was with "vascular dementia," memory problems usually linked to small strokes, and not the scarier classic Alzheimer's disease.

Now those lines are blurring as specialists realize that many if not most patients have a mix of the two dementias. Somehow, factors like hypertension — blood pressure readings of 140 over 90 or higher — that weaken arteries also seem to spur Alzheimer's diseaselike processes.

One suspect: scarring known as white matter lesions. White matter acts as the brain's telephone network, a system of axons, or nerve fibers, that allow brain cells to communicate with each other. Recent studies have shown that elevated blood pressure can damage the tiny blood vessels that nourish white matter, interrupting those signals.

The NIH in a few months will begin enrolling 7,500 hypertension patients age 55 and older around the country. The test: whether aggressive treatment to lower systolic blood pressure below 120 — what's considered normal — will prove healthier than today's guidelines that urge getting it below 140, or 130 for diabetics.

The main focus is on heart and kidney health. But all participants will be screened for dementia, and a subset will undergo repeated cognitive testing and MRI scans to tell if lowering blood pressure also protects against dementia.

National Institutes of Health to study high blood pressure's link to dementia 01/27/10 [Last modified: Wednesday, January 27, 2010 5:33pm]

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