High Levels of HDL Cholesterol Linked to Dementia: Study

MRI brain of a dementia patient with left parietal atrophy asymmetry. (Atthapon Raksthaput/Shutterstock)

Researchers have discovered high levels of high-density lipoprotein cholesterol (HDL-C) could be associated with a greater risk of dementia.

The study, led by Monash University and published in the Lancet Regional Health Western Pacific, involved thousands of people from Australia and the United States over more than six years.

HDL cholesterol is also known as “good cholesterol” due to its ability to remove other types of cholesterol from the bloodstream.

The researchers recorded 850 incidences of dementia in a mammoth 18,668 people.

The scientists found individuals with high HDL-C of more than 80 milligrams per deciliter had a 27 percent greater risk of dementia.

In addition, the researchers found there was a 42 percent rise in dementia risk for those participants older than 75.

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“High HDL-C is associated with an increased risk of all-cause dementia in both middle-aged and older individuals,” the paper stated.

“The association appears strongest in those 75 years and above.”

Even after taking into account variables including age, sex, country, daily exercise, education, alcohol consumption, and weight change over time, the association between high HDL-C and dementia remained “significant.”

Monash University School of Public Health and Preventive Medicine senior research fellow Ms. Monira Hussain said the study may help improve understanding of dementia, but more research is needed.

“While we know HDL cholesterol is important for cardiovascular health, this study suggests that we need further research to understand the role of very high HDL cholesterol in the context of brain health,” she said.

“It may be beneficial to consider very high HDL cholesterol levels in prediction algorithms for  dementia risk.”

Large Cohort Recruited For The Study

Scientists recruited 16,703 Australians older than 70 years for the study, as well as 2,411 people older than 65 years from the United States.

The individuals examined during the research had no cardiovascular disease, dementia, physical disability, or life-threatening illness at the time of recruitment for the study and were cognitively healthy.

The researchers noted that while multiple studies have shown a link between HDL-C and adverse health events, evidence regarding its connection to dementia is still unknown.

An analysis of a medical database examining the association between high HDL cholesterol and dementia found only one study from Denmark that established a link.

“Only one study of cohorts from Denmark was identified which suggested that high HDL-C is associated with dementia in people aged 47–68 years,” the research paper noted.

“Since early onset dementia may have different pathophysiology than late-onset dementia, it is important to extend these results in well-characterised prospective studies of older people who are cognitively intact at the study onset.”

The data analysis was conducted between October 2022 and January 2023, before publishing the study.

The authors noted their study is the “most comprehensive study” to report high HDL-C and the risk of dementia in the elderly.

The trial was funded with the support of Monash University, the National Institutes of Health, USA, the National Health and Medical Research Council of Australia, and the Victorian Cancer Agency.