"Statins do NOT cause memory loss despite fears they could harm cognitive health," reports the Mail Online.
Statins are widely prescribed to lower cholesterol in people at risk of a heart attack or stroke. However, some people have reported problems with memory or thinking abilities (cognition) after starting statins.
Previous trials of statins did not look at memory or cognition specifically, and studies that have looked for a link since have used differing memory tests, making it hard to compare findings.
This study tested the memory and overall cognitive function of 1,037 people aged 70 to 90 at several points over a 6-year period. At the end of the study, researchers did not find any differences in memory and thinking ability between participants who took statins and those who did not.
Find out more about statins and why they are used.
Where did the story come from?
The researchers who carried out the study were from the University of New South Wales and St Vincent's Hospital, both in Australia. The study was funded by the Australian Government's National Health and Medical Research Council and published in the peer-reviewed Journal of the American College of Cardiology.
The Mail Online story said that the study had found no link between statins and memory loss, but said that people in the study had been on statins for 9 years – missing the point that many of the people in the study had not used statins at all. That means it’s hard to understand from the Mail Online story how the researchers carried out the study.
The Mail Online, the Daily Telegraph and The Sun all included comments that statins may offer protection against memory loss. The Sun said the drugs "may even protect OAPs against Alzheimers". While the study found evidence that some people who started statins during the 6-year trial had slower memory loss, that does not mean they were protected against Alzheimer’s disease by statins. The slower memory loss could be for other reasons.
What kind of research was this?
This was a cohort-study. Cohort studies are good ways to spot links (or rule out links) between suspected risk factors – in this case statins – and outcomes such as memory loss. However, they do not explain how the link came about, so even if the study had found a link, it would not prove that statins were the cause of memory loss.
What did the research involve?
Researchers recruited 1,037 Australian adults aged 70 to 90. They filled in health questionnaires, were weighed and measured, and took a series of tests to assess their overall cognition and memory.
They were followed up for 6 years, with 12 tests of their cognition and memory repeated every 2 years, so that people who took all the tests took them 4 times in total.
In addition, researchers asked people to take MRI brain scans. Around half (529) had MRI scans to measure their brain volume, and 408 of them had the scan repeated after 4 years.
People taking statins are more likely to have heart disease and high blood pressure, which means they are at more risk of dementia in older age. That might affect the results. So researchers adjusted the results to take account of a range of potential confounding factors including:
- sex and age
- years spent in education
- non-English speaking background
- body mass index
- heart disease
- high blood pressure
- presence of a type of protein called APOE4, known to increase Alzheimer's disease risk
They looked to see whether, after taking these factors into account, people who had never taken statins had more or less decline in cognition and memory over 6 years, compared to people who:
- had taken statins at any point in their lives
- took statins continuously during the study
- who started statins during the study.
What were the basic results?
All the people in the study showed some decline in memory and cognition over 6 years, regardless of whether they took statins or not.
Looking at the main measures of memory and cognition tests, researchers found no difference between people who:
- had never taken statins
- who had taken statins at some point in their lives
- who took statins continuously through the study
- who started taking statins during the study
There was no difference between these groups in brain volume as measured by the MRI scan.
Of the people in the study, 395 had never used statins and 642 had used statins, for an average of 9 years before the start of the study. 99 people started taking statins during the study.
When researchers looked at this last group, they found that their rate of memory decline on 1 test was slower than people who had never used statins. It is unclear what the significance of this finding is.
How did the researchers interpret the results?
The researchers said: "Statin use in the elderly population was not associated with any acceleration in decline in memory, global cognition, or brain volumes in community-dwelling elderly Australians." They added: "This study offers reassurance to consumers who hold concerns about harmful statin effects on memory and cognition."
Statins are widely used drugs in the UK. The National Institute for Health and Care Excellence (NICE) says they can be offered to people with a 10% risk of having a heart attack in the next 10 years. But concerns have been raised about offering statins to people who are otherwise healthy, because of the possible risk of side effects.
This study seems to suggest that fears over a link between statins and cognitive decline or memory loss are unfounded. The study found no link between the drugs and mental decline.
The significance of the reported "protection" against memory loss for people starting statins is unclear. Because of the type of study, we do not know why these people were prescribed statins while others were not. Doctors might be more likely to prescribe statins to people over 70 who seem to be mentally sharp, rather than people who already seem affected by memory loss. That could mean people prescribed statins have less memory loss – but not because of the statin. Previous studies have not found any evidence that statins prevent dementia.
There are a few limitations with the study. Complete data was only available for 55% of the people who started the study, and those who dropped out were older and had lower cognitive scores. The type of study also means we are limited in how we can interpret the results.
However, the research is good news for people who are considering taking statins but are worried about possible side effects. This study suggests that they are unlikely to cause problems with memory or general cognitive function.
If you are taking statins it is recommended that you do not stop taking them without speaking to a GP.
Analysis by Bazian
Edited by NHS Website
Links to the headlines
The Telegraph online, 18 November 2019
The Times online (subscription online), 19 November 2019
The Sun, 18 November 2019
Mail Online, 19 November 2019
Links to the science
Journal of the American College of Cardiology. Published online November 18 2019