Cholesterol-lowering drugs May not prevent Alzheimer's

In the recent online edition of "Neurology," the medical journal of the American Academy of Neurology, new findings were reported by a study showing no evidence that statins slow or prevent Alzheimer's disease as previously thought. Statins are very widely used for heart conditions and lowering cholesterol and high blood pressure. They include the prescription drugs Lipitor, Lescol, Mevacor, Altocor, Pravachol, Zocor, and Crestor. In the past, animal research suggested that statins may help ward off certain kinds of brain conditions. Researchers found that taking the cholesterol-lowering agents was associated with a slower cognitive decline and results also suggested that they may have a therapeutic benefit by a mechanism independent from the cholesterol-lowering action.

The objective of this study was to examine the relation of statins to incident Alzheimer's disease and change in cognition and neuropathology.

"We didn't find a relation between statin use and the risk of Alzheimer's disease or a decline in thinking ability," said lead researcher Dr. Zoe Arvanitakis, an associate professor of neurology at Rush University Medical Center and member of the American Academy of Neurology.

This study looked at over 900 Catholic clergy. At the start of the study, all the participants were around 75 years old and had no signs of dementia. All of the participants agreed to a brain autopsy at the time of their death and underwent annual cognitive tests for up to 12 years. When the brain autopsies were performed, statins were measured by a global measure as five cognitive systems.

When asked to describe the study Arvanitakis said, "When the study started, 119 people were taking statins. Over the 12 years of the study, 191 people developed Alzheimer's. Of these, only 16 had been taking statins." She also said the type of statin use did not make a difference in developing Alzheimer's.

"We grouped them as more readily crossing the blood brain barrier or not and we did not see a relationship in either type," said Arvanitakis.

The blood brain barrier is a structure that protects the brain from foreign substances in the blood that may injure it like viruses or bacteria. High blood pressure and stress open the blood brain barrier. Alzheimer's disease may be caused or aggravated further due to a breakdown in this blood brain barrier.

However, Arvanitakis does not think this study is conclusive. She says future studies will need to look at the possibility of associations of statins with other pathologic changes of Alzheimer's disease not examined in this study.

"The effect is unclear and we need to continue to examine this question carefully to determine whether statins are beneficial or not," said Arvanitkis. "There are two clinical trials being available next year and we need to wait for that important data to become available. The results of these ongoing studies will help better understand the effect of Alzheimer's and statins although existing observational studies do not suggest that statins are beneficial."