A large new study has found that people with lower levels of LDL cholesterol—commonly known as “bad” cholesterol—have a reduced risk of developing dementia, including Alzheimer’s disease.
The research, published online in the Journal of Neurology, Neurosurgery & Psychiatry, also suggests that statin medications may offer additional protection for people with low LDL cholesterol.
LDL cholesterol is widely known for its role in heart disease. High levels can lead to plaque buildup in arteries, increasing the risk of heart attacks and strokes. Doctors often prescribe statins to lower LDL cholesterol and reduce the chance of cardiovascular events. But until now, it hasn’t been clear whether lowering LDL cholesterol might also protect the brain.
In this study, researchers looked at data from 11 university hospitals involving adult outpatients who had no prior diagnosis of dementia. Each patient was followed for at least six months after an LDL cholesterol test.
The researchers focused on two main groups: nearly 192,000 people with LDL levels lower than 1.8 mmol/L (less than 70 mg/dL) and about 379,000 people with LDL levels higher than 3.4 mmol/L (more than 130 mg/dL). They matched individuals in both groups based on age, sex, and other factors, ending up with over 108,000 matched pairs for comparison.
The findings were clear: people with LDL cholesterol levels below 1.8 mmol/L had a 26% lower risk of developing any form of dementia and a 28% lower risk of Alzheimer’s-related dementia compared to those with much higher LDL levels. This suggests that keeping LDL cholesterol at moderate low levels might help protect brain function as people age.
However, the study also revealed a limit to this benefit. While lowering LDL cholesterol to below 1.4 mmol/L (55 mg/dL) still showed some protection—about an 18% lower risk—the benefit stopped once levels dropped below 0.8 mmol/L (30 mg/dL). At that very low level, the risk reduction disappeared entirely.
The researchers also looked at the effect of statins, the drugs commonly used to lower cholesterol. Among those with LDL levels under 1.8 mmol/L, people who took statins had a further 13% reduction in overall dementia risk and a 12% reduction in Alzheimer’s risk compared to people who weren’t taking the drugs.
This supports the idea that statins may have brain-protective benefits in addition to lowering cholesterol.
It’s important to note that this was an observational study, meaning the researchers looked at existing data rather than conducting a controlled experiment. That means they can’t say for sure that low LDL cholesterol causes a lower risk of dementia—only that the two appear to be linked.
The study also has a few limitations. Because it relied on hospital records, there may have been differences in how dementia was diagnosed. Additionally, LDL levels were only measured once at the beginning, and cholesterol levels can change over time.
Despite these caveats, the findings offer new insight into how cholesterol may affect brain health. The authors concluded that maintaining LDL cholesterol levels below 1.8 mmol/L (70 mg/dL) could help reduce the risk of cognitive decline and dementia. They also emphasized the added value of statin therapy in this context.
In summary, while more research is needed to understand the full relationship between cholesterol and brain health, this study adds to growing evidence that managing LDL cholesterol isn’t just good for the heart—it might also be good for the mind.
If you care about Alzheimer’s, please read studies about the likely cause of Alzheimer’s disease, and new non-drug treatment that could help prevent Alzheimer’s.
For more information about brain health, please see recent studies about diet that may help prevent Alzheimer’s, and results showing some dementia cases could be prevented by changing these 12 things.
The research findings can be found in the Journal of Neurology Neurosurgery & Psychiatry.
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