High levels of good cholesterol and low levels of bad cholesterol are correlated with lower levels of the amyloid plaque deposition in the brain that is a hallmark ofAlzheimers disease, in a pattern that mirrors therelationship between good and bad cholesterol in cardiovascular disease, UC Davisresearchers have found.

Our study shows thatbothhigher levels of HDL good and lower levels of LDLbad cholesterol in the bloodstream are associated with lower levels of amyloidplaque depositsin the brain,”said Bruce Reed, lead study author and associate director of the UC Davis Alzheimers Disease Center.

Unhealthy patterns of cholesterol could be directly causing the higher levels of amyloid known to contribute to Alzheimers, in the same way that such patterns promote heart disease, he said.

The relationship between elevated cholesterol and increased risk of Alzheimers disease has been known for some time, but the current study is the first to specifically link cholesterol to amyloid deposits in living humanstudy participants, Reed said.

The study, Associations Between Serum Cholesterol Levels and Cerebral Amyloidosis, is published online today in JAMA Neurology.

In the United States, cholesterol levels are measured in milligrams (mg) of cholesterol per deciliter (dL) of blood.For HDL cholesterol, a level of 60 mg/dl or higher is best. ForLDL cholesterol,a level of70mg/dL or loweris recommended for people at very high risk of heart disease.

Charles DeCarli, director of the Alzheimers Disease Center and an author of the study, said it is a wake-up call that, just as people can influence their late-life brain health by limiting vascular brain injurythrough controlling their blood pressure, the same is true of getting a handle on their serum cholesterol levels.

If you have an LDL above 100 or an HDL that is less than 40, even if youre taking a statin drug, you want to make sure that you are getting those numbers into alignment, DeCarli said. You have to get the HDL up and the LDL down.

The study was conducted in 74 diverse male and female individuals 70 years and older who were recruited from California stroke clinics, support groups, senior facilities and the Alzheimers Disease Center. They included three individuals with mild dementia, 33 who were cognitively normal and 38 who had mild cognitive impairment.

The participants amyloid levels were obtained using a tracer that binds with amyloid plaques and imaging their brains using PET scans. Higher fasting levels of LDL and lower levels of HDL both were associated with greater brain amyloid a first-time finding linking cholesterol fractions in the blood and amyloid deposition in the brain. The researchers did not study the mechanism for how cholesterol promotes amyloid deposits.

Recent guidelines instituted by the American College of Cardiology, the American Heart Association and the National Heart, Lung, and Blood Institute have suggested abandoning guidelines for LDL targets. Reed said that recommendation may be an instance in which the adage thatwhats good for the heart is good for the brain does not apply.

This study provides a reason to certainly continue cholesterol treatment in people who are developing memory loss, regardless of concerns regarding theircardiovascular health,”said Reed, a professor in the UC Davis Department of Neurology.

It also suggests a method of lowering amyloid levels in people who are middle aged, when such build-up is just starting,”he said. “If modifying cholesterol levels in the brain early in life turns out to reduce amyloid deposits late in life,we could potentially make a significant difference in reducing the prevalence of Alzheimers, a goal of an enormous amount of research and drug development effort.

The studys other authors are Sylvia Villeneuve and William Jagust of UC Berkeley and Wendy Mack and Helena C. Chui of the University of Southern California.

The research was supported by grants P01 AG12435, AG034570 and P30 AG10129 from the National Institute on Aging of the National Institutes of Health. Villeneuve received support from the Canadian Institutes of Health.