Changes in cholesterol in older adults are associated with increased risk of dementia

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The study showed that the risk was highest in people whose cholesterol became more unstable as it rose, rather than in people whose cholesterol was steadily decreasing. Survey results They are being presented Sunday at the American Heart Association's Scientific Sessions in Chicago and are considered preliminary until the full results are published in a peer-reviewed journal.

The findings suggest that “significantly lower or higher cholesterol levels in older adults may serve as an early warning sign of potential cognitive problems and early stages of dementia.” said Dr. Jen Chou, principal investigator of the study and researcher at the Institute of Graduate Studies. Public Health and Preventive Medicine, Monash University, Melbourne, Australia. “Monitoring cholesterol changes over time in older adults may be helpful in implementing early and targeted prevention strategies.”

However, Zhou said the study results should not be misunderstood as suggesting that people should avoid lowering cholesterol levels that are too high. “Lowering cholesterol levels is a well-established way to reduce the risk of cardiovascular disease.”

Cholesterol is a waxy, fat-like substance in the blood that is produced by the liver but also comes from food, primarily animal products such as meat, eggs, cheese, and milk. Cholesterol is measured not only as total cholesterol but also by its components. Low-density lipoproteins (LDL) are considered “bad” cholesterol because too much can cause plaque in the arteries, while high-density lipoproteins (HDL) are considered “good” cholesterol. Because it helps reduce the risk of heart disease and stroke. Triglycerides are another type of fat that can contribute to unhealthy cholesterol buildup.

High cholesterol has been shown to not only cause cardiovascular disease, but also increase the risk of dementia. Millions of American adults have cholesterol levels outside of the healthy range, with research suggesting total cholesterol is about 150 milligrams per deciliter and LDL is less than 100 mg/dL. You can lower this level by eating a healthier diet, being more physically active, and taking medications, such as statins, prescribed by your health care professional.

In this study, researchers wanted to see whether unintentional fluctuations in cholesterol from year to year were associated with poorer cognitive function and earlier onset of dementia than stable cholesterol levels.

The analysis looked at 9,846 U.S. and Australian adults enrolled in the Aspirin Reduction in Elderly Events Trial (ASPREE), which is investigating whether low-dose aspirin can help prevent age-related diseases such as dementia and heart disease. data was used. The trial also measured participants' cholesterol levels and was expanded into an observational study.

Total cholesterol, LDL, HDL, and triglycerides were measured at study entry and during annual visits during the first 3 years of the study. Those who started or stopped taking lipid-lowering drugs during the measurement period of the study were excluded from the analysis. Participants were at least 65 years old and had no history of cardiovascular events, dementia, or cognitive problems.

Participants were divided into four groups based on how much their total cholesterol and LDL changed over a three-year period. After more than 5 years of follow-up, those with the greatest variation in total cholesterol were 60% more likely to develop dementia and 23% more likely to show cognitive decline than those with the least variation. Ta. People with the highest fluctuations in LDL cholesterol were 48% more likely to develop dementia and 27% more likely to show cognitive decline than those with the lowest fluctuations.

There was no association between HDL or triglycerides and dementia or cognitive decline. There were also no significant differences between those who used lipid-lowering drugs and those who did not.

Sudha Seshadri, Ph.D., founding director of the Glenn Biggs Alzheimer's and Neurodegenerative Disease Research Institute at UT Health San Antonio, said this observational study does not show that cholesterol fluctuations are the cause of dementia; I only pointed out that two conditions are related.

“Variations may not lead to dementia,” she says. “It could be a sign of something else. For example, are we finding discrepancies in lifestyle behavior, and are those discrepancies occurring because a person's cognitive function is starting to decline?” Is it? I need to understand if that's the cause or if it's indicative of something else.”

In recent years, researchers have become increasingly interested in the role that variations in cardiovascular risk factors play in heart and brain health. However, most studies have focused on blood pressure, heart rate and blood sugar levels, Zhou said.

He said future research needs to investigate the causes of changes in cholesterol and whether dementia begins to develop before or as a result of changes in cholesterol. said. She also wondered if other chronic conditions might be involved.

“One possible explanation is that large fluctuations in (total and LDL) cholesterol levels may destabilize atherosclerotic plaques, which are primarily composed of LDL cholesterol.” said Zhou. This destabilization of plaque within the artery can increase the risk of plaque growth, rupture, and subsequent obstruction of blood flow to the brain, she said.

Seshadri, who was not involved in the study, stressed that people with high cholesterol need to continue taking steps to lower their levels.

“Make sure to follow the lipid-lowering regimen your doctor has advised you,” Dr. Seshadri says. “Don't just stop taking your statin. Or, even if you eat well for a week, don't binge eat or drink for two weeks. Either way, consistency is what your doctor advises, and that's why this… This may be the message you get from it.”

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