Cholesterol Level Above Which Brain Disease Risk Increases
High LDL or "bad" cholesterol, which is the main risk factor for heart and stroke, is also a contributing factor in the development of Alzheimer's disease and dementia. The latest study identifies the "threshold" value of these harmful lipids above which the risk of brain diseases increases.
Low-density lipoprotein (LDL) – commonly known as "bad" cholesterol – carries cholesterol that accumulates as plaque inside blood vessels. LDL cholesterol levels can progress for years without any noticeable symptoms, which is why high cholesterol is also called the "silent killer," as it is often discovered only after a heart attack occurs.
When it comes to desirable LDL cholesterol values, the latest recommendations state – "the lower, the better." The universal guideline is: everyone should have an LDL cholesterol level below 3 millimoles per liter (mmol/L). These desirable cholesterol levels are significantly lower for people at risk of cardiovascular disease.
Numerous studies have clearly shown that the risk of heart attack drops drastically with lower LDL cholesterol levels, and more and more research supports the notion that the lower the cholesterol level – the lower the risk of dementia.
Cholesterol Threshold for Dementia and Alzheimer's Disease Risk
The latest study by researchers from Hallym University in South Korea shows that individuals with low LDL cholesterol levels have a lower risk of dementia and Alzheimer’s disease.
Additionally, researchers determined the LDL cholesterol value above which the risk of dementia and Alzheimer's disease increases, and that threshold is:
0.8 mmol/L, or less than 30 milligrams per deciliter (mg/dL).
The risk significantly increases from 1.8 mmol/L (less than 70 mg/dL).
In other words, the risk of developing dementia or Alzheimer's disease significantly rises with an increase in bad cholesterol from 1.8 mmol/L (less than 70 mg/dL), but it already appears at 0.8 mmol/L (less than 30 mg/dL).
What Does a Cholesterol Level Below 0.8 mmol/L Mean?
Specifically, LDL levels below 1.8 mmol/L (less than 70 mg/dL) were associated with a 26% reduction in risk of all-cause dementia and a 28% lower risk of Alzheimer’s-related dementia, compared to levels higher than 130 mg/dL.
With LDL levels below 1.4 mmol/L (<55 mg/dL), an 18% reduction was observed for both diseases, and when LDL levels dropped below 0.8 mmol/L (less than 30 mg/dL), the risk of dementia and Alzheimer's disease disappeared.
Researchers reached these findings after collecting data from 11 university hospitals on adult patients with no previous dementia diagnosis, who were followed for at least 180 days after the LDL test.
The study by Hallym University scientists was published in the journal "Journal of Neurology Neurosurgery & Psychiatry".
