Cholesterol-lowering drug statins 'safe' and do not cause memory loss, says study
The study allays fears of statins adversely affecting memory function or brain health. The researchers also found that in people with risk factors for dementia, statin use slowed down cognitive decline.
Statins - one of the most prescribed drugs worldwide for high cholesterol - do not cause memory loss, according to a new analysis. The research team, which assessed individuals over six years, did not find a link between statin medication and cognitive decline.
The researchers also found that statin use is even protective against memory decline in some individuals at risk of dementia.
There have been fears among patients that the use of statins may have side effects, such as a negative impact on cognitive health. The findings, experts say, suggest that the use of statins to lower cholesterol levels does not adversely affect memory function and is, therefore, a reassurance for consumers to feel more confident about their statin prescription.
"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", says the study's first author Dr. Katherine Samaras, an endocrinologist at St Vincent's Hospital Sydney.
"There is strong evidence that they reduce mortality in our patients with heart disease, stroke, diabetes, renal disease, and other lipid disorders. Most importantly, statins aren't associated with a risk for major adverse health advents. These findings will hopefully go a long way toward reducing consumers' concerns about memory and cognition from statins, so they don't stop taking these life-saving medications", says Dr. Samaras, who is head of the Clinical Obesity, Nutrition and Adipose Biology lab at the Garvan Institute of Medical Research, Sydney.
How do statins work?
Having high blood cholesterol raises the risk of heart disease and stroke. A simple blood test can check cholesterol levels.
Statins have been prescribed since the 1990s to treat people with heart disease or high cholesterol to reduce the risk of future heart disease events. The US Centers for Disease Control and Prevention (CDC) says that a little more than half of the US adults - 55% or 43 million - who could benefit from cholesterol medicine, are currently taking it.
The US Food and Drug Administration (FDA) describes statins as a class of medicines used to lower cholesterol in the blood. Most of the cholesterol in the blood is made by the liver.
Statins work by reducing the amount of cholesterol made by the liver and by helping the liver remove cholesterol that is already in the blood.
However, isolated case reports of cognitive decline in statin users have concerned some consumers. Up to half the individuals prescribed statin therapy do not fill their prescriptions mainly due to this concern, which carries a significant impact on public health, says Dr. Samaras.
The study findings
Accordingly, the research team examined changes to the brain in 1,037 elderly individuals, measuring five areas of cognition. They used 13 different tests and MRI scans of the brain, over six years.
The team used data from the Sydney Memory and Ageing Study, an observational study of older community-dwelling people at the Centre for Healthy Brain Ageing (CHeBA), University of New South Wales, Sydney.
"Five memory tests were used to assess new learning and short and long-term recall using verbal and visual memory tasks. Global cognition evaluated memory plus processing speed, language, visuospatial ability, and executive function", says the study published in the Journal of the American College of Cardiology.
Psychologists and nurses collected data every two years on four occasions over the six-year period. Clinicians diagnosed the presence of heart disease, cerebrovascular disease, hypertension, and Type 2 diabetes.
Participants' medications and duration of use were categorized - there were 395 statin "never-users" and 642 statin "ever-users." On average, participants had been on statins for nine years. When the study was initiated, there was no significant difference in the rate of either memory decline or cognition in the two groups.
The analysis after six years shows that there was no difference in the rate of memory or cognitive decline of statin-users compared to never-users.
Participants who took statins continuously over the study period had significantly "higher baseline performance in memory and global cognition" compared to never-users. When researchers compared the 99 participants who started statins during the study period, they found statin initiation was associated with a lessening in the rate of decline of memory. Overall, the team found no link between statin use and cognition between the start of the study and after six years of observation.
"Controlling for important and potentially contributory factors, such as age, sex, and obesity, we found no difference in the rate by which memory and other aspects of cognition changed over time, between statin users and those who had never used the medication. There was also no difference in the change in brain volumes between the two groups", says Dr. Samaras.
The researchers also found that in people with risk factors for dementia, including heart disease or diabetes, statin use slowed down cognitive decline, compared to those with the same risk factors, who did not take statin medication.
"There was a protective interaction between statin ever-use, heart disease, and the six-year change in the total learning memory test score. Among patients with heart disease, statin ever-users displayed a slower rate of decline on this test compared to never-users. However, in patients without heart disease, there was a comparable rate of decline between statin ever-users and never-users. The study also found a protective interaction between statin ever-use and the rate of decline in long-delayed recall performance for patients carrying the APOE-4 genotype. Carriers of this genotype are at high risk of Alzheimer's disease", the findings state.
In an accompanying editorial, Dr. Costantino Iadecola, and Dr. Neal S. Parikh, from Weill Cornell Medicine, New York City, says that the study supports the view that worries about cognitive impairment should not limit statin use. The data "raise the possibility that statins may favorably alter cognitive trajectories in a group of elders at high risk of Alzheimer's disease", say the experts.