Concerns that cholesterol-lowering statin drugs can impair brain health appear to be unfounded, according to new research.
"Statins won't make you stupid or cause memory loss," said lead researcher Dr Katherine Samaras, a professor of medicine at St. Vincent's Clinical School of Medicine in Darlinghurst, Australia.
Black box warning
And for some people at risk of dementia, statins like Lipitor (atorvastatin) and Crestor (rosuvastatin) may improve memory and mental functioning, her team found.
Many millions of people take statins because of heart disease or high cholesterol. But reports that the drugs could cause memory loss led the US Food and Drug Administration in 2012 to require a black box warning on all statin medications, she said.
However, "we could find no overall impact on memory or any other aspect of cognitive function over six years in a large population of older people, who had extensive testing every two years," Samaras said.
The observational nature of this study means the research can't be considered conclusive, only that a strong link exists, the researchers noted.
"Any person who takes statins and is concerned about their memory and cognition should discuss this with their doctor. However, overall, we should be greatly reassured by the study findings," Samaras said.
For the study, she and her colleagues collected data on more than 1 000 people aged 70 to 90 who took part in the Sydney Memory and Aging Study. About 600 took statins and had done so for an average of nine years.
Slower rate of memory loss
All of the participants had their memory and cognitive skills – such as processing speed and language – tested at the start of the study. No difference was seen between statin users and nonusers, according to the report.
Some people also had MRI scans to assess their brain volume. The MRIs showed no significant difference in brain volume among statin users and nonusers over two years.
And over six years, the researchers found no significant difference between memory and mental ability among those who did and didn't take the drugs.
Among 99 people who started taking statins during the study, however, Samaras and colleagues found statins were linked to a slower rate of memory loss.
As expected, statins did protect people with heart disease from heart attacks. Within this group, the drug also resulted in a slower rate of a decline in memory, compared with people who didn't take statins.
Moreover, in people with heart disease, diabetes or other risk factors for dementia, statin use slowed down mental decline in comparison with nonusers who had the same conditions.
Many effects on the brain
Looking at people who had the APOE-4 gene mutation, which puts them at high risk for Alzheimer's disease, the researchers found statins appeared to significantly slow the rate of mental decline.
However, among participants without heart disease who took statins, the rate of memory decline was similar to those who didn't take the drug, the findings showed.
The report was published online in the Journal of the American College of Cardiology.
Dr Costantino Iadecola, a professor of neurology and neuroscience at Weill Cornell Medicine in New York City, co-authored an editorial accompanying the study. He said, "Statins have many effects on the brain."
The brain is 80% fat and has the most cholesterol of any organ in the body, and is very sensitive to any changes in fat, said Iadecola.
"So it's not surprising that modulating cholesterol affects the brain," he said.
Reducing cholesterol in the brain may reduce two changes linked to Alzheimer's, namely beta-amyloid plaques and tau tangles, he noted.
But whether statins have a positive effect on preserving cognitive function requires more study, Iadecola said.
In the meantime, he doesn't advise taking statins for the sole purpose of maintaining your mental abilities, since these drugs can have side effects.
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