Study Finds That HDL Or "Good" Cholesterol Could Be Linked to Dementia

The Gist:

• High-density lipoprotein, or HDL, cholesterol is sometimes categorized as "good" cholesterol for its ability to reduce the risk of heart issues.
• A study published on Oct. 4, 2023, suggests that HDL cholesterol could increase the risk of dementia, especially in older adults.

Let's face it: making decisions for your health isn't always the easiest when there is constantly changing information. Scientists continue to study the negative effects of climate change on the human body, but they also continue to probe into diseases like Alzheimer's and dementia.

In a study published on Oct. 4, 2023, research suggests that HDL cholesterol, previously considered "good" cholesterol, could increase the risk for dementia in older adults. Here's what you need to know.

According to the Centers for Disease Control and Prevention (CDC), two types of lipoproteins carry cholesterol in the body: LDL (low-density lipoprotein) cholesterol and HDL (high-density lipoprotein) cholesterol.

LDL cholesterol is sometimes referred to as the "bad" cholesterol, and high levels of LDL build up in your arteries as plaque and can lead to heart disease or stroke.

HDL cholesterol, however, is sometimes called the "good" cholesterol because it absorbs the cholesterol in your blood and carries it back to the liver, where it's flushed out of the body. High levels of HDL can reduce your risk of heart disease or stroke!

The CDC recommends people keep their total cholesterol at roughly 150 mg/dL, or milligrams per deciliter of blood.

Despite HDL cholesterol being referred to as a "good" cholesterol, it might not be enough to reduce your risk for dementia. On Oct. 4, 2023, a study published in Neurology found that high or low HDL cholesterol levels could increase the risk of dementia in elderly adults. However, the study did not find a direct correlation between HDL cholesterol and dementia.

The participants for the study included over 184,000 Kaiser Permanente Northern California health plan members who were 55 years of age or older. No members of the group had dementia when the study began. The participants were initially surveyed between 2002 and 2007 and then had blood tests taken no more than two years after they completed the survey. They were also divided into three groups based on their initial HDL cholesterol levels, with adjustments made for risk factors.

Researchers used a combination of surveys and electronic records to track the participants' health over roughly 13 years, with a follow-up survey presented to participants in 2020. After the study, just 25,000 of the participants had developed dementia.

The result of the study revealed that, per the abstract, "Both low and high levels of HDL-C were associated with elevated dementia risk. The association between LDL-C and dementia risk was modest."

The study's lead author, Erin Ferguson, a doctoral student at the University of California San Francisco, ultimately concluded that more research into HDL cholesterol was needed and could even be a "modifiable risk factor" later in life, per NBC News.