There is no link between statin use and memory impairment, researchers have concluded, after evaluating effects of the cholesterol-lowering drugs over 6 years in more than 1,000 older people in Australia.
A team from the Garvan Institute of Medical Research and the University of New South Wales (UNSW), both in Sydney, Australia, led the study.
"Over 6 years, there was no difference in the rate of decline in memory or global cognition between statin users and never users," they write in a recent Journal of the American College of Cardiology paper on the findings.
In fact, for certain individuals, statins may even offer some protection against memory decline, they suggest.
The results show that, among participants with risk factors for dementia, those who used statins had a slower rate of decline in memory and thinking skills than those who did not use the drugs.
The researchers hope that the findings will help to allay fears among consumers who have become concerned following reports of isolated cases of statin users experiencing cognitive decline.
"Many factors can contribute to the cognitive symptoms that isolated case reports describe," says first study author Katherine Samaras, who is a professor at the Garvan Institute and head of its Clinical Obesity, Nutrition, and Adipose Biology Lab.
Results are 'reassuring'
Dr. Perminder Sachdev, a professor of neuropsychiatry at UNSW and co-director of its Centre for Healthy Brain Ageing, is the study's senior author.
He says, "In this study, our data reassuringly suggests that the use of statins to lower cholesterol levels is not likely to adversely affect memory function."
Dr. Sachdev cautions, however, that because the study was observational and not a clinical trial, the findings are not conclusive.
"However," he adds, "the evidence is mounting that statins are safe in relation to brain health, and this concern should not preclude their use in individuals who are likely to benefit from lower cholesterol levels."
Statins are among the more widely prescribed drugs. Since the 1990s, doctors have been prescribing them for people with heart disease or high cholesterol in order to reduce the risk of cardiovascular events such as heart attack and stroke.
Prof. Samaras says that up to half of people do not fill their statin prescription, mainly because they are concerned about reports of individuals experiencing cognitive decline from statin use.
"We carried out the most comprehensive analysis of cognition in elderly statin users to date, and found no results to support that cholesterol-lowering statins cause memory impairment," she notes.
No link to faster decline in memory, cognition
For the new study, the team used data from the prospective, observational Sydney Memory and Ageing Study.
The study participants were 1,037 people living in Sydney. Data collection began in 2005, when they were free of dementia and between 70 and 90 years old.
Over 6 years, the participants took 13 different tests to assess five areas of memory and cognition. They also underwent MRI scans to assess changes to their brains.
After adjusting the results to control for potential influencers, such as sex, age, and weight, the researchers found no difference in the rate of change in memory and other features of cognition between those who used statins and those who did not.
"There was also no difference in the change in brain volumes between the two groups," observes Prof. Samaras, who is also an endocrinologist at St Vincent's Hospital, in Sydney.
In addition, she and colleagues saw a slowing of cognitive decline among statin users with heart disease, diabetes, or other risk factors for dementia, compared with participants who had never used this type of drug.
"Our findings," she adds, "demonstrate how crucial a healthy metabolism is to brain function and how therapies can modulate this to promote healthy aging."
"What we've come away with from this study is a reassurance for consumers to feel more confident about their statin prescription."
Prof. Katherine Samaras