High cholesterol in middle age significantly increases the risk of Alzheimer's disease and other types of dementia in old age. Researchers from the Kaiser Permanente health organization in Oakland, California studied 9,844 men and women whose cholesterol levels were measured between the ages of 40 and 45. 30 years later the participants' medical records were reviewed. 469 of them had Alzheimer's disease and 127 had vascular dementia, another form of dementia caused by clogged blood vessels and other conditions affecting blood supply to the brain. The study found that in people with high cholesterol the risk of developing Alzheimer's was 57% higher. Even people with only 'borderline' higher cholesterol had a 50% higher chance of vascular dementia. It is thought that nearly 100 million Americans have either high or borderline cholesterol.
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