Study suggests it may cause the effect through cerebrovascular disease
MONDAY, Dec. 10 (HealthDay News) -- High blood pressure may be associated with increased risk for mild cognitive impairment, says a study by researchers at the Columbia University Medical Center in New York City.
Mild cognitive impairment, which causes learning and thinking difficulties, has "attracted increasing interest during the past years, particularly as a means of identifying the early stages of Alzheimer's disease as a target for treatment and prevention," the study authors wrote.
They followed 918 Medicare recipients aged 65 and older (average age 76.3) who were assessed every 18 months for an average of 4.7 years. None of the participants had mild cognitive impairment at the start of the study, but 334 of them developed the condition during the study period.
Of those, 160 developed amnestic mild cognitive impairment (which involves low scores on memory portions of neuropsychological tests), and 174 developed non-amnestic mild cognitive impairment. Hypertension was associated with an increased risk of all types of mild cognitive impairment, especially non-amnestic mild cognitive impairment, the researchers said.
The findings are published in the December issue of the Archives of Neurology.
"The mechanism by which blood pressure affects the risk of cognitive impairment or dementia remains unclear. 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 study authors wrote.
"Our findings support the hypothesis that hypertension increases the risk of incident mild cognitive impairment, especially non-amnestic mild cognitive impairment," the researchers concluded. "Preventing and treating hypertension may have an important impact in lowering the risk of cognitive impairment."
The Alzheimer's Association has more about mild cognitive impairment.
-- Robert Preidt
SOURCE: JAMA/Archives journals, news release, Dec. 10, 2007
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