ISLAMABAD, July 2 (Online): Elderly people whose blood pressure drops suddenly may be about to develop Alzheimer's or other forms of dementia, researchers in Sweden reported on Thursday.
Patients whose systolic blood pressure -- the top number -- dropped 15 points or more in six years or less had triple the risk of Alzheimer's disease or other dementia, the team at the Karolinska Institutet in Stockholm found.
"Our findings imply that poor blood flow in the brain, resulting from an extensive decline in blood pressure, may promote the dementia process," Dr. Chengxuan Qiu, who led the study, said in a statement.
"These findings indicate a possible threshold level in systolic pressure, especially for people with vascular disease in whom further reduction of blood pressure under this level may precipitate dementia onset," Qiu added.
"Using antihypertensive medications is important for high blood pressure and related disorders, but our findings suggest that it is necessary to monitor these drugs in the very old to avoid a probable dangerous drop of blood pressure under a certain threshold."
Writing in the journal Stroke, the researchers said they studied 947 people aged 75 or more who had no evidence of dementia. They were examined initially and three and six years later.
At three years, 147 were diagnosed with Alzheimer's disease and 39 with other dementia. After six years an additional 91 had Alzheimer's and 27 more were diagnosed with other types of dementia.
"Our data show no substantial differences in blood pressure levels at enrollment between non-demented persons and those that were demented three to six years later," said Dr. Bengt Winblad, a professor of geriatric medicine at Karolinska Institutet.
"However, some elderly people who experience a significant decline in systolic blood pressure three to six years before diagnosis do have an increased risk of dementia and Alzheimer's disease."
The researchers said it is possible that degeneration of cells in the parts of the brain that regulate blood pressure may cause the pressure to fall. That could mean the low blood pressure was a symptom of dementia that could accelerate an already ongoing process.
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