A report in the December, 2007 issue of Archives of Neurology claims that high blood pressure can increase the risk of mild cognitive impairment, affecting the ability to thinking and learning.
About 9.9 of every 1000 elderly people who do not have dementia develop mild cognitive impairment early, and of these, 10%-12% develop Alzheimer’s disease. compared with 1%-2% of the general population. Dr. Christiane Reitz, M.D., Ph.D., and colleagues at the Columbia University Medical Center, New York, monitored 918 Medicare patients with an average age of 76.3 years, starting in 1992 through 1994. None had any mild cognitive impairment. Participants were then checked every 18 months, for an average of 4.7 years. People with mild cognitive impairment registered low cognitive scores and a defective memory, but were not diagnosed with dementia.
334 people developed mild cognitive impairment during the follow-up phase— including 160 cases of amnestic mild cognitive impairment, and 174 cases of non-amnestic mild cognitive impairment. High Blood pressure was connected with an increased risk of all types of mild cognitive impairment that was mostly associated with an increased risk of non-amnestic mild cognitive impairment. Hypertension was not associated with amnestic mild cognitive impairment, or a change in memory and language
"The mechanisms by which blood pressure affects the risk of cognitive impairment or dementia remain unclear," the authors write. "Hypertension may cause cognitive impairment through cerebrovascular disease. Hypertension is a risk factor for subcortical white matter lesions found commonly in Alzheimer’s disease. Hypertension may also contribute to a blood-brain barrier dysfunction, which has been suggested to be involved in the cause of Alzheimer’s disease. Other possible explanations for the association are shared risk factors," including the formation of cell-damaging compounds known as free radicals.
The authors believe that their findings support the hypothesis that hypertension increases the risk of incident mild cognitive impairment, especially non-amnestic mild cognitive impairment They conclude that preventing and treating hypertension may be important in lowering the risk of cognitive impairment.
Source: American Medical Association (AMA)