April 21, 2010
Men and women who have high blood pressure in middle age are at increased risk of Alzheimer’s disease, studies confirm. And seniors with memory problems are similarly more likely to develop Alzheimer’s and other forms of dementia, whether they have high blood pressure or not. Now, a study from the large and ongoing Canadian Study of Health and Aging shows that seniors with high blood pressure who have problems organizing their thoughts and making decisions, despite having intact memories, are at increased risk of Alzheimer’s as well. The findings appeared in the Archives of Neurology, a medical journal from the American Medical Association.
In the current study, researchers from the University of Western Ontario studied 990 older adults, most of whom were in their 80s. All had mild cognitive impairment, which causes problems in thinking and memory, and some had high blood pressure.
Some seniors with mild cognitive impairment have problems primarily with memory, and they are more likely to develop Alzheimer’s disease. Others, including those who suffer a stroke, are more likely to have problems with so-called executive function, which causes problems with making decisions and judgments.
The researchers looked at the seniors for five years. They found that Alzheimer’s disease and other forms of dementia developed in about 60 percent of those who had memory problems, regardless of whether they had high blood pressure or blood pressure that was under control.
But among those with thinking problems but no memory deficits, having high blood pressure was much more likely to lead to dementia. Almost 58 percent of those with thinking problems went on to develop dementia, compared to 28 percent of those whose blood pressure was under control.
High blood pressure is known to damage blood vessels throughout the body, including the brain. Therefore, keeping blood pressure in check may be important for maintaining brain health, especially when the brain may be under assault from other disease processes related to Alzheimer’s.
The researchers concluded that maintaining healthy blood pressure into old age may be critical for lowering the risk of developing Alzheimer’s disease. About a third of seniors with mild cognitive impairment have problems primarily with thinking. “Control of hypertension in this population could decrease by one-half the projected 50-percent five-year rate of progression to dementia,” the researchers concluded.
Shahram Oveisgharan; Vladimir Hachinski: "Hypertension, Executive Dysfunction, and Progression to Dementia: The Canadian Study of Health and Aging." Archives of Neurology, Vol. 67(No. 2), Feb. 2010, pages 187-192.