Written by Jennifer Arnouville, DO, FAAFP | Reviewed by Karla Robinson, MD
Key takeaways:
Statins are commonly used medications. They’re very effective at lowering cholesterol and are considered safe.
Some research shows a link between statin use and dementia. But other studies show a protective effect by statins.
The research on statins and dementia isn’t clear-cut. But if your cholesterol is in an unhealthy range, the significant benefits of a statin may outweigh the risk of its uncommon side effects.
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Statins are powerful cholesterol-lowering medications. They’re among the most prescribed medications in the U.S. Common examples of statins include atorvastatin, rosuvastatin, and simvastatin. But there has been concern about whether these medications might have bad effects on the brain — like causing dementia.
Many people who take statins have reported changes in their memory or feeling like they have a foggy head. These are examples of cognitive side effects, meaning they affect how someone thinks. This has led to a lot of discussion about a possible link between statins and dementia.
Some reports have warned that statins may increase dementia risk. But other reports have found that statins actually protect against dementia. In fact, in an analysis of 36 studies, researchers found statins to be associated with a lowered risk of dementia (OR 0.80).
Let’s take a closer look at the evidence to set the record straight on statins and dementia.
The link between statins and dementia
Scientists have been working hard to figure out if statins might be causing dementia — or any other harm to the brain. Below are some of the largest studies and what they showed.
A recent expert review gathered data from 24 different studies that looked at the link between statins and dementia. These studies collectively included more than 1 million people, ages 60 years and older:
Main finding: They didn’t find a significant link between statin medications and dementia.
Limitations: The longest study followed people for 15 years. So researchers suggested that future studies should follow people for longer.
A 2021 study looked at data of more than 18,000 adults older than 65 years who were taking statins.
Main finding: There was no significant link between statins and dementia — or statins and any cognitive impairment.
Limitations: These people took different types of statin medications. And it was a retrospective analysis, which means the data wasn’t initially collected to look for this link. This can make the data a little harder to interpret.
A 2019 Australian study of more than 1,000 participants measured memory and brain volumes in people older than 70 years who were taking statins.
Main finding: When comparing people taking statins with those who didn’t, there was no difference in cognition, memory loss, or brain volume. Interestingly, those who started a statin during the study seemed to have a slower rate of memory loss.
Limitations: This was a well-designed trial, but it should be repeated on larger numbers of people to make sure these findings stand.
A large 2019 study of more than 28,000 older adults followed them for 5 years after a concussion. Concussion increases the risk for dementia. So a significant amount of study participants developed dementia in this time period. Researchers looked at whether people taking statins had increased dementia.
Main finding: Among people with a concussion in this study, 1 in 6 developed dementia. People who were taking a statin had a moderate reduction in dementia. Specifically, they were 13% less likely to develop dementia.
Limitations: This finding doesn’t necessarily apply to all adults. It looked specifically at people who had a concussion and were at increased risk of dementia.
So do statins increase or decrease the risk of dementia?
A recent review article tried to address this question. The answer isn’t so clear-cut because there are so many other factors that can affect the risk of dementia. This can make statins appear to have an effect on the risk of dementia in a study when in fact it may not.
Some of the issues that the researchers found are:
Genetics: People with certain gene variations are more likely to develop dementia.
Ethnicity: Different ethnicities may process statins in a way that can change the risk of dementia.
Sex: Dementia risk in men and women can differ between statins.
Age: Getting older is the major risk factor for dementia.
Medical conditions: High blood pressure, cardiovascular disease, diabetes, and gum disease are risk factors for dementia. Treating these medical conditions may decrease dementia.
So far, there’s no convincing evidence that statins increase someone’s risk of dementia. A fair number of studies show that statins might have a protective effect on the brain and reduce dementia risk. In either case, the research is ongoing. But currently, the best research suggests the benefits of statin therapy outweigh potential risks.
What are the differences between lipophilic and hydrophilic statins?
Statins can be divided into lipophilic and hydrophilic subtypes. Lipophilic statins (like atorvastatin and simvastatin) are more fat soluble. They can easily enter more tissues throughout the body — like the brain and muscles. Hydrophilic statins (like rosuvastatin and pravastatin) are more water soluble. They mainly have action in the liver.
Some studies show that hydrophilic statins have a more protective effect against dementia than lipophilic statins. But the data is mixed, and that’s largely because there are many more factors that can affect the risk of dementia.
Some of the other theoretical differences between lipophilic and hydrophilic statins include:
Hydrophilic statins may have less systemic side effects like muscle aches.
Hydrophilic statins may reduce the risk of heart failure more as compared with lipophilic statins.
Lipophilic statins may lower LDL cholesterol greater than hydrophilic statins.
Medical researchers emphasize that the evidence to favor either type of statin isn’t compelling. More research is needed to see if the solubility of statins has a significant effect on clinical outcomes.
What about statins and Alzheimer’s?
Alzheimer’s disease is the most common form of dementia in the U.S. Statin use is also very common. Many people who take statins may develop Alzheimer’s. But that doesn’t mean that statins caused the person to get Alzheimer’s. They may simply occur together.
What does the evidence say about the relationship between Alzheimer’s and statins? One study published in 2020 followed 288,000 people for 3 years. They found a nearly 50% lower rate of new onset Alzheimer’s disease in people who took statins.
Another research group did a meta analysis of data from 30 different studies. The studies included nearly 10 million people over the course of 18 years. They found a 30% lower rate of Alzheimer’s in people taking statins (RR .69). A meta analysis isn’t a controlled experiment, but the data are promising. It suggests that better controlled studies are needed to answer this important question.
Are there other neurological side effects of statins?
The research looks promising that statins aren’t likely to be a major risk for dementia. But there’s still the question of whether there are other brain-damaging effects from statins.
The jury is still out on this matter.
Many of the studies above looked at cognitive symptoms and memory loss. They didn’t find evidence that statins increase the risk of these symptoms. Similar to dementia, some of the data suggests statins protected against memory loss.
But there’s also quality research that shows possible links with Parkinson’s disease and peripheral neuropathy. At the same time, there’s at least equally strong evidence showing that statins may protect against these neurologic diseases.
More research is needed to understand the effect of statins on neurological diseases.
Which statins don’t cause peripheral neuropathy?
There’s no clear-cut evidence on which statins are best when it comes to avoiding peripheral neuropathy. That’s because there’s no solid evidence that they’re even responsible for neuropathy in the first place. It’s an uncommon complication, which generally goes away when the statin is discontinued.
But there’s some evidence that hydrophilic statins (like fluvastatin) may be better than lipophilic statins. Taking niacin along with statins may also help prevent neuropathy, but the evidence is not definitive.
If you experience pins-and-needles sensation after starting a statin, talk with your primary care professional right away. The quicker the medication is stopped, the more likely the neuropathy is to resolve.
The bottom line
Statins are common medications that are used to lower cholesterol in people who may also have many risk factors for dementia. This makes it more likely to see dementia in people taking statins, but that doesn’t mean statins are linked to dementia. It’s difficult for experts to know if statins increase the risk for dementia and the research is mixed.
Making the decision to start a statin can be difficult — especially when considering the risk of side effects. Having an open discussion with your healthcare professional, who knows your medical history, can make decisions about medications a bit easier.
References
Adhikari, A., et al. (2021). Association between statin use and cognitive function: A systematic review of randomized clinical trials and observational studies. Journal of Clinical Lipidology.
Al-Kuraishy, H. M., et al. (2019). Statins, an oft-prescribed drug is implicated in peripheral neuropathy: The time to know more. The Journal of the Pakistan Medical Association.
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