Even Moderate Elevations of Cholesterol Predispose to the Two Types of Dementia
Posted Aug 07 2009 11:58am
Most people know about Alzheimer's disease but few are aware of the second most common cause of dementia, vascular dementia. That's probably because the latter condition is poorly understood and little discussed in the media. The name, however, provides a clue. The three most common mechanisms of vascular dementia are multiple
brain cortical infarcts, a strategic single infarct, and small vessel disease (see: Vascular Dementia ). There's now evidence that both types of dementia have a relationship to serum cholesterol and that even moderate levels of it in midlife can put you at risk (see: Study Shows Even Moderately Elevated Cholesterol Level Boosts Dementia Risk ). Below is an excerpt from the article:
Elevated cholesterol levels in midlife – even levels considered only borderline elevated – significantly increase the risk of Alzheimer’s disease and vascular dementia later in life, according to a new study... (see: Midlife Serum Cholesterol and Increased Risk of Alzheimer’s and Vascular Dementia Three Decades Later ) ....Even borderline cholesterol levels (200 – 239 mg/dL) in midlife raised risk for late-life vascular dementia by nearly the same amount: 52 percent. Vascular dementia, the second most common form of dementia after Alzheimer’s disease, is a group of dementia syndromes caused by conditions affecting the blood supply to the brain. Scientists are still trying to pinpoint the genetic factors and lifestyle causes for Alzheimer’s disease....[T]his study is the largest long-term study with the most diverse population to examine the midlife cholesterol levels and late-life dementia. It is also the first study to look at borderline high cholesterol levels and vascular dementia, rather than just Alzheimer’s disease.“Our findings add to the existing body of evidence on a degree of overlap between two dementia types in terms of risk factors, symptoms and neuropathology,” said the study’s lead author.... “Dementia and cardiovascular disease are common major health problems, share several risk factors and often occur simultaneously, interacting with one another. A holistic approach that addresses multiple major health problems simultaneously is needed to effectively manage these disorders.”
I found this article to fascinating. Many years ago, I asked my an internist friend whether it could be possible to take one's cholesterol level too low with statins, exercise, and dietary control. After all, cholesterol is a major component of cellular membranes. He said, "I'd advise anyone to try to lower it as much as possible." Now we learn, at least from the perspective of dementia and heart health, that this was sound advice. Although it's reasonable to assume that dementia and cardiovascular disease share multiple risk factors, I never had them strongly linked in my mind. However, they will remain bound together from now on. As a pathologist who has performed many autopsies, I am all too familiar with atherosclerotic plaques in the aorta, coronary arteries, and carotid arteries. Obviously, many of these patients had high cholesterol levels. In my experience, however, it was unusual to see smaller arteries with lipid deposits. However, there's still much to learn about the relationship between small vessel disease, dementia, and cholesterol levels. There's now another good reason to keep your cholesterol levels in good control.