• Cholesterol is an essential fatty substance produced by the liver and consumed in food.
• However, high cholesterol levels can cause health problems, including coronary heart disease.
• A new study suggests that in older people, fluctuating cholesterol levels may increase the risk of dementia.
• Researchers suggest that annual cholesterol tracking could be used to assess the risk of dementia and cognitive decline in older adults.

Cholesterol is a waxy, fat-like substance produced by the liver essential for making cell membranes, some hormones and bile salts for fat digestion.

It can also be consumed in many foods, inclusive meat, seafood, poultry, eggs and dairy products. However, the Centers for Disease Control and Prevention (CDC) we recommend that people avoid eating too many foods high in cholesterol, as this can lead to health problems such as heart attacks and strokes.

High cholesterol it can develop as a result of dietary and lifestyle factors, but it can also be the result of genetics, certain health conditions and certain medications. The CDC states that about 25 million adults in the United States have high cholesterol — 240 milligrams per deciliter (mg/dL) or higher.

• high-density lipoprotein-cholesterol (HDL-C) – this is also known as “good” cholesterol because it absorbs cholesterol from the blood and returns it to the liver for excretion from the body
• low-density lipoprotein (LDL-C) – also known as “bad” cholesterol, makes up most of the cholesterol in the body, and high levels mean it can build up in the arteries, leading to heart disease and stroke cerebrovascular.

New research suggests that not only high cholesterol, but also fluctuating cholesterol levels can influence health.

The study, presented at the American Heart Association Scientific Sessions 2024and which has not yet undergone peer review, found that in older adults, annual changes in cholesterol levels may increase the risk of dementia and cognitive decline.

Emer MacSweeney, MDa consultant neuroradiologist at Re:Cognition Health, who was not involved in this research, explained why such changes might have this effect.

She said Today’s medical news that:

“Cholesterol fluctuations, particularly LDL cholesterol, may increase the risk of dementia due to their potential impact on atherosclerotic plaque stability. Plaque destabilization can lead to an increased risk of plaque rupture and restricted blood flow, which affects brain function.”

Of the 9,846 participants, all in their 70s, 87% living in Australia and the rest in the US, all had no dementia at the start of the study, and 32% were on cholesterol-lowering drugswhich they remained throughout the study.

During the 3 years of the study, participants underwent annual tests of total cholesterol, LDL-C, HDL-C and triglycerides — another fatty substance that comes from the diet and is found in the blood.

The researchers divided them into four groups based on how much their cholesterol fluctuated, from the most to the least fluctuations.

They then monitored the participants for 6 years for the development of dementia and cognitive decline. A panel of experts reviewed cognitive test results, self-reported cognitive problems, and medical reports of dementia diagnosis or dementia medication prescription.

The researchers then compared the numbers with dementia and cognitive decline in the groups with the highest and lowest cholesterol levels.

During the 6 years of follow-up, 509 people developed dementia and 1,760 developed cognitive decline without dementia.

The researchers found associations between fluctuating total cholesterol and LDL-C levels and dementia, but not with fluctuating HDL-C or triglycerides.

People with the most fluctuating total cholesterol levels had a 60 percent greater likelihood of dementia and a 23 percent increase in cognitive decline, compared to those with the most stable cholesterol levels.

Those with the greatest fluctuations in LDL-C had a 48% higher risk of dementia and a 27% higher risk of cognitive decline.

They also experienced faster declines in overall cognitive health, memory and reaction speed.

“Because the brain relies heavily on stable blood flow and oxygenation, disruptions can lead to damage to neurons and other brain cells, potentially accelerating cognitive decline. LDL cholesterol is linked to inflammation, which can also contribute to neurological deterioration over time. Additionally, fluctuations in cholesterol levels may reflect underlying health instability or dysregulated lipid metabolism, both of which may play a role in cognitive impairment.”

– Emer MacSweeney, MD

Lead author Zhen Zhou, Ph.Da postdoctoral researcher at the School of Public Health and Preventive Medicine at Monash University in Melbourne, Australia, said in a press release that “elderly people with fluctuating cholesterol levels are not related to having taken lipid-lowering drugs – especially those experiencing large year-to-year variations – may warrant closer monitoring and proactive preventive interventions.”

Zhou called for further studies. “We need future studies to help us understand the relationship between cholesterol variability and dementia risk,” she said in the press release, asking, “Are cholesterol variability levels a real risk factor, a precursor, or a biomarker of dementia risk?”

MacSweeney also stressed the need for more studies, particularly in more diverse populations, as 96 percent of those in this study were white, to investigate “how cholesterol fluctuations directly contribute to cognitive decline at the cellular or molecular level, particularly in the brain”. and “whether cholesterol variability is linked to other dementia biomarkers, potentially improving early diagnosis and intervention strategies.”

In their study abstract, the authors suggested that “tracking variability in TC (total cholesterol) and LDL-C measured annually may serve as a novel biomarker for higher risk of incident dementia and cognitive decline in older adults.”

However, Clifford Segil, DOa neurologist at Providence Saint John’s Health Center in Santa Monica, CA, who was not involved in the study, was not entirely convinced by the findings.

he said MNT that: “Annual cholesterol monitoring is part of annual physicals, and lipids are directly related to the risk of heart attack and stroke. After reading this article, it does not appear that it will be useful in clinical practice anytime soon to monitor annual lipid profiles or cholesterol levels in terms of assessing a patient’s risk of developing dementia.”

“LDL, or bad cholesterol, and total cholesterol levels are not accepted risk factors in developing dementia, but they are watched very closely to prevent heart attacks or strokes,” he explained.