People with a history of hypertension (high blood pressure) appear to be at increased risk of developing mild cognitive impairment, a condition that involves difficulties with thinking and learning, investigators at Columbia University College of Physicians and Surgeons report.
"Mild cognitive impairment 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," they note in a report published in the journal Archives of Neurology.
About 9.9 of every 1 000 elderly individuals without dementia develop mild cognitive impairment each year. Of those, 10 percent to 12 percent progress to full-blown Alzheimer's disease each year, compared with 1 percent to 2 percent of the general population.
Dr Jose A. Luchsinger and colleagues followed 918 US Medicare recipients age 65 and older without mild cognitive impairment beginning in 1992 through 1994. Roughly two-thirds of them had high blood pressure.
During an average follow up of about 5 years, 334 of the study subjects developed mild cognitive impairment, including 160 cases of "amnesic" mild cognitive impairment, which involves low scores on memory portions of brain function tests, and 174 cases of non-amnesic mild cognitive impairment.
40% increased risk
High blood pressure was associated with a 40 percent increased risk of all types of mild cognitive impairment that was mostly driven by an increased risk of non-amnesic mild cognitive impairment, the investigators report. High blood pressure appeared to raise the risk of non-amnesic mild cognitive impairment by 70 percent.
Use of antihypertensive medication had no apparent effect on the link between high blood pressure and mild cognitive difficulties.
"Preventing and treating hypertension may have an important impact in lowering the risk of cognitive impairment," the investigators conclude.
SOURCE: Archives of Neurology, December 2007. – (Reuters Health)