Here's some good, if preliminary, news for the millions of people who take statin drugs to lower their cholesterol: A new review of existing research finds no evidence that the medications pose a risk to brainpower.
Instead, the review suggests that statins may actually lower the risk of dementia, although the researchers say that's not certain.
The findings, which contradict a warning label required by the US Food and Drug Administration (FDA), aren't conclusive. And a physician who specializes in blood vessel disorders said it remains wise for doctors to take patients off the drugs or switch them if there are signs of cognitive (thinking) problems.
Still, the new findings are "very reassuring", said study co-author Dr Seth Martin, a cardiovascular prevention fellow at Johns Hopkins Hospital.
At issue are the statin drugs – including well-known medications such as Zocor and Lipitor – that doctors prescribe to patients with high cholesterol. In 2012, the FDA warned consumers that "cognitive (brain-related) impairment, such as memory loss, forgetfulness and confusion, has been reported by some statin users." Warning labels appeared on the drug packaging, too.
While the brain-related problems appeared to be quite rare, "the message received by a lot of folks was that this is a big worry that people need to go in and talk to their physicians about," Martin said.
Martin and colleagues decided to look at every related study they could find to get a wide view of the possible risk. They then focused on research they considered to be of high quality.
Based on eight studies, the investigators didn't find evidence that patients who take the drugs in the short term face a higher risk of brain-related problems. "We found no reason for physicians to be concerned," said study lead author Dr Kristopher Swiger, an internal medicine physician at Johns Hopkins Hospital.
Five of eight studies involving patients who took the drugs for at least a year (and even as long as 25 years or more) found that they actually had lower risks of dementia. Three studies focused specifically on Alzheimer's disease. When findings were combined, the studies suggest that one in 50 people may gain a reduction in dementia risk by taking the drug for an average of six years.
It's not clear, however, if the statins are directly responsible for the difference in dementia risk.
The new review did not receive any drug industry funding.
More good than harm
Dr Orli Etingin, a professor of clinical medicine at Weill Cornell Medical College-New York Presbyterian Hospital and a specialist in blood vessel disorders, said it remains clear that "statins do more good than harm."
The review appears to be valid, but the studies themselves may miss small changes in the brainpower of patients, said Etingin, who was not involved with the new research.
If a patient appears to have cognitive problems, she said, it's "safe and reasonable" to remove the medication for a few weeks and see what happens. If the patient's cognition improves, another statin might be appropriate.
Why might statins affect the brain either positively or negatively? On one hand, Etingin said, "what's good for the heart is usually good for the brain." But there could be other effects, she said, that aren't yet understood.
The study appeared in the journal Mayo Clinic Proceedings.
For more about statins, visit the US National Library of Medicine.