In older adults, a decrease in blood pressure (BP) over time may warn of dementia, according to a Swedish study. Compared with people with stable BP readings, those whose systolic pressure dropped 15 points or more in 6 years or less were three times more likely to develop Alzheimer's disease or other forms of dementia.
Researchers studied 947 people age 75 or older with no signs of dementia. Study subjects were examined at the study's outset, 3 years later, and 6 years later.
At 3 years, 147 of the people had Alzheimer's disease and 39 had other forms of dementia. At 6 years, an additional 91 people had Alzheimer's disease and 27 had another form of dementia.
Researchers found that BP markedly decreased during the 3-year period before a dementia diagnosis and continued afterward.
Researchers are unsure whether the drop in BP is a cause or an effect of dementia. They speculate that reduced blood flow to the brain accelerates the development of dementia. Another possibility is that the brain cell degeneration characteristic of dementia damages parts of the brain that regulate BP.
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