Keeping cholesterol levels healthy can be good for the brain as well as the heart, according to a newly published study. The results come at a time when some experts are questioning new recommendations for the prescription of statins to address cholesterol levels to prevent cardiovascular disease.
People with high levels of “good” HDL cholesterol and low levels of “bad” LDL cholesterol in their blood are likely to have fewer plaques associated with Alzheimer’s disease in their brains, say researchers publishing their findings in JAMA Neurology. The investigators reached their conclusion after scanning the brains of 74 men and women aged at least 70 years; 33 had normal cognition, 38 had mild cognitive impairment and three had mild dementia.
“Unhealthy patterns of cholesterol could be directly causing the higher levels of amyloid known to contribute to Alzheimer’s, in the same way that such patterns promote heart disease,” says lead author Bruce Reed, PhD, neurology professor and director of the Alzheimer’s Disease Center at the University of California, Davis. The prevalence of Alzheimer’s disease ultimately could be reduced significantly, he adds, if further research corroborates the results of this study, which suggest that modifying cholesterol levels in the brain early in life may reduce amyloid deposits late in life. For now, Reed says, the study "provides a reason to certainly continue cholesterol treatment in people who are developing memory loss, regardless of concerns regarding their cardiovascular health."
The UC Davis researchers maintain that, in light of their findings, LDL targets would be useful for clinicians treating those with dementia or those who could develop dementia. Newly revised clinical practice guidelines for the prescription of statins to address cholesterol to prevent cardiovascular disease recommend the elimination of LDL targets, however. The guidelines were published in November by the American Heart Association (AHA) and the American College of Cardiology (ACC).
Heart and vascular specialists at the Cleveland Clinic also recommend continuing the use of LDL-C target goals and have additional concerns with the new guidelines, including the potential overtreatment of seniors.
The guidelines recommend the prescription of statins to lower the circulation of cholesterol in the blood:
- For those aged 40 to 75 years who don’t have cardiovascular disease but are determined to have a 7.5 percent or higher risk for a heart attack or stroke within 10 years. The previous guidelines recommended that people should be prescribed a statin only if their 10-year risk exceeded 20 percent, and the former guidelines did not factor in stroke risk.
- For people with a history of heart attack, stroke, stable or unstable angina, peripheral artery disease, transient ischemic attack or coronary or other arterial revascularization.
- People aged 40 to 75 years who have type 1 or 2 diabetes.
The new guidelines include a risk calculator to enable clinicians to factor in gender and ethnicity in their predictions of heart attack and stroke risk. The Clinic physicians recommend an individualized approach to treating cholesterol issues, and they also recommend a more comprehensive risk assessment than the risk calculator proposed in the new guidelines.
The Clinic doctors are not the only ones to raise questions about the guidelines. Several days after the guidelines were released, officials from the AHA and ACC defended them.
“We stand behind our guidelines, the process that was used to create them and the degree to which they were rigorously reviewed by experts,” said Mariell Jessup, MD, AHA president. The guidelines do not replace clinical judgment and should be used to drive individualized care, added John Gordon Harold, MD, ACC president.
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