HDL Cholesterol and Dementia Risk

HDL Cholesterol and Dementia Risk

High or Low Levels of HDL Cholesterol Linked to Increased Risk of Dementia


While HDL cholesterol is often considered the “good” kind of cholesterol that promotes heart and brain health, new research suggests that both high and low levels of HDL cholesterol may increase a person’s risk of developing dementia.

The study, conducted by researchers at Boston University, involved a large group of participants and took into account a long follow-up period, providing valuable insights into the links between cholesterol levels and dementia. However, it is important to note that the study could not establish a causal relationship between high or low levels of HDL cholesterol and dementia, as cautioned by the American Academy of Neurology (AAN).

To investigate further, the researchers analyzed data from over 184,000 participants from the Kaiser Permanente Northern California Health Plan, with an average age of 70. None of the individuals had dementia at the beginning of the study. The participants completed a survey on their health behaviors and had their cholesterol levels measured during routine healthcare visits, with an average of 2.5 measurements over the following two years. The researchers then followed the participants using their electronic health records for an average of nine years, during which over 25,000 individuals developed dementia.

The study found that the average HDL cholesterol level among the participants was 53.7 milligrams per deciliter (mg/dL), with healthy levels typically above 40 mg/dL for men and above 50 mg/dL for women. The researchers divided the participants into five groups based on their HDL cholesterol levels. Surprisingly, those with both the highest levels of HDL cholesterol (65 mg/dL or higher) and the lowest levels (11 to 41 mg/dL) had increased rates of dementia compared to those in the middle group. However, the increase in dementia rates for those with high levels of HDL cholesterol was greater at 15%, while those with low levels had a 7% higher rate of dementia compared to the middle group. It is worth noting that the higher dementia rates among individuals with low HDL cholesterol were still lower than those with high cholesterol levels.

Notably, the study also examined LDL cholesterol, commonly known as “bad” cholesterol, but only found a slight association with the risk of dementia. This finding further highlights the complex nature of the relationship between HDL cholesterol and health conditions such as heart disease, cancer, and now dementia.

The results of the study were published online in Neurology, the medical journal of the American Academy of Neurology. Maria Glymour, the study author, commented on the unexpected findings, stating, “The elevation in dementia risk with both high and low levels of HDL cholesterol was unexpected, but these increases are small, and their clinical significance is uncertain.”

Dr. Howard Weintraub, clinical director of the Center for the Prevention of Cardiovascular Disease at NYU Langone Heart in New York, also expressed surprise at the results, stating that higher levels of HDL cholesterol, such as 90 or 100 mg/dL, were associated with dementia, but lower levels of around 63 mg/dL were not typically associated with increased risk.

Although the study provides valuable insights, it does not definitively establish a cause-and-effect relationship between HDL cholesterol levels and dementia. Further research is needed to fully understand the implications of these findings. In the meantime, it is important for individuals to maintain healthy cholesterol levels through lifestyle modifications and consult with healthcare professionals for personalized advice.


Question: One of the first symptoms of Alzheimer’s disease is __________________.

Answer: As memory loss and cognitive decline are the hallmark symptoms of Alzheimer’s disease, memory loss would be one of the first noticeable signs.