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Researchers at Kaiser Permanente's Division of Research, Oakland, CA, and the University of Kuopio in Finland, have completed a 40-year study on the effects of high cholesterol levels during midlife years. The study associates elevated cholesterol levels with dementia.

Men and women with high cholesterol levels (240 mg/dL or higher) were found to have a 66 percent greater chance of developing Alzheimer's disease later in life. Borderline high levels (200-239 mg/dL) raised the risk of developing vascular dementia in late-life by 52 percent.

Syndrome of Symptoms

Vascular dementia, the second most common form of dementia after Alzheimer's disease, is caused by conditions that affect blood supply to the brain. It is not a single disease, but rather a syndrome of dementia symptoms such as memory problems, lack of concentration, slurred speech, loss of bladder or bowel control, and other abnormal behavioral patterns.

The study's senior author, Rachel Whitmer, PhD, a research scientist and epidemiologist at the Kaiser Permanente Division of Research, stated in a press release, "Our study shows that even moderately high cholesterol levels in your 40s puts people at greater risk for Alzheimer's disease and vascular dementia decades later."

Cholesterol levels of 9,844 Kaiser Permanente members were obtained between 1964 and 1973 when they were 40-45 years old. The participants were then followed for 40 years making it the first and largest long-term study of a diverse population to examine midlife cholesterol levels and late-life dementia, rather than Alzheimer's disease alone.

Between 1994 and 2007, vascular dementia or Alzheimer's disease was diagnosed in 598 participants, when they were between 61 and 88 years old.

Another of the study's authors, Alina Solomon, MD, a researcher with the department of neurology at the University of Kuopio, said in the release, "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.

"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."

According to Solomon, there are still more questions to be answered.

Difficult to Study

When study subjects' cholesterol levels were first measured it was not standard practice to measure LDL and HDL, so the study used total cholesterol. Therefore, Solomon noted, the significance of LDL and HDL in relation to dementia needs to be studied.

The brain is the most cholesterol-rich organ in the human body, but brain cholesterol is difficult to study.

"Circulating and brain cholesterol are separated by the blood-brain barrier, and not so much is currently known about the interactions between the two cholesterol pools," Solomon said.

"How does plasma cholesterol influence brain cholesterol? What role do disturbances in brain cholesterol metabolism play in diseases leading to dementia? The exact mechanisms behind the cholesterol-dementia association remain to be determined."

When asked about specific prevention or treatment recommendations Solomon told ADVANCE:

"The lifestyle recommendations for preventing heart disease also apply to dementia. This is good news; cholesterol is a modifiable risk factor for dementia, and everyone can make simple lifestyle changes to increase their chances of staying healthy.

"We do not recommend lipid-lowering medication as a first-line measure. Statins should be taken only by certain people, at the physician's indication, according to current guidelines.

 "What's good for the heart is also good for the mind."

Melissa Moye is a nurse at North Florida Regional Medical Center, Gainesville, FL.