Dementia: High and low levels of 'good' cholesterol may increase risk

Evan Walker
Evan Walker TheMediTary.Com |
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Experts say it’s important to keep close watch on your cholesterol levels. FG Trade/Getty Images
  • A new study of older adults found a link between extreme levels of “good” HDL cholesterol and a small increase in dementia risk later in life.
  • The research tracked more than 184,000 adults for 17 years and found both high and low HDL cholesterol was associated with greater odds of developing dementia compared to middle-range levels.
  • However, no clear associations emerged between “bad” LDL cholesterol and dementia except in statin users, suggesting complex relationships between cholesterol and cognitive decline.

New research, published today in the journal Neurology, reports that high levels as well as low levels of “good” HDL cholesterol were associated with a higher risk of developing dementia.

The study involved more than 184,000 participants with an average of 70 years who were followed for 17 years.

The researchers were seeking to understand the relationship between two types of cholesterol, HDL-C and LDL-C, and the likelihood of developing dementia in older age.

While there have been some studies on this topic, not many have considered the influence of statin medications or examined the possibility of more complex associations.

The researchers explored these connections using extensive data from both survey responses and electronic health records.

The researchers reported that people with the highest HDL cholesterol levels had a 15% higher dementia risk compared to those with mid-range levels.

Those with the lowest HDL levels had a 7% higher dementia risk versus the mid-range group.

Researchers said these relationships held even after accounting for other factors such as alcohol use, hypertension, cardiovascular disease, and diabetes.

On the other hand, levels of “bad” LDL-C cholesterol didn’t show a clear link to dementia risk for everyone. However, for those who were using statins, a higher LDL-C level indicated a slightly higher dementia risk.

Age also seemed to play a role in the relationship between HDL-C and dementia risk but not with LDL-C.

While this large study shows associations, it cannot prove high or low HDL cholesterol levels directly cause dementia.

Erin Ferguson, MPH, a lead study author and a former Boston University SPH student currently affiliated with the University of California San Francisco, told Medical News Today that “we found a U-shaped relationship between HDL-C and dementia risk, such that people with either lower or higher HDL-C had a slightly elevated risk of dementia.”

“Overall, we found no association between LDL-C and dementia,” Ferguson added.

Clifford Segil, DO, a neurologist at Providence Saint John’s Health Center in Calilfornia who was not involved in this research, told Medical News Today that “studies looking into how to prevent dementia are appreciated as our treatments for dementia in 2023 continue to only provide modest clinical improvements.”

As a reminder, the three most common dementias are Alzheimer’s dementia, vascular or multi-infarct dementia, and Lewy-Body dementia or Parkinson’s dementia. Statin use, or medication used to lower cholesterol in our blood, has been proven to decrease a risk of second lifetime heart attack and stroke. Statin use needs to be studied specifically regarding decreasing the risk of multi-infarct of vascular dementia.

Dr. Clifford Segil

“This study looked at using cholesterol-lowering medications to decrease all dementia rather than statin use to decrease multi-infarct or vascular dementia,” Dr. Segil pointed out.

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