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MELBOURNE — For older adults watching their cholesterol, maintaining steady levels might be just as important as keeping them low, according to new research. A preliminary study set to be presented at this year’s American Heart Association Scientific Sessions reveals that significant year-to-year swings in cholesterol levels could be an early warning sign of impending cognitive decline or dementia.
The discovery comes from a massive study of nearly 10,000 older adults, offering a new perspective on the complex relationship between heart health and brain function. While doctors have long monitored cholesterol levels as a snapshot of cardiovascular health, this research suggests that the stability of these levels over time might tell an equally important story about cognitive health.
“Older people with fluctuating cholesterol levels unrelated to whether they were taking lipid-lowering medications – particularly those experiencing big year-to-year variations — may warrant closer monitoring and proactive preventive interventions,” explains lead author Zhen Zhou, Ph.D., a postdoctoral research fellow at Monash University’s School of Public Health and Preventive Medicine in Melbourne, in a statement.
Think of cholesterol levels like the stock market – while everyone focuses on whether it’s high or low, this study suggests that wild swings might be just as concerning as consistently high levels. The research found that people whose total cholesterol levels bounced around the most (in the top 25% of variability) faced a startling 60% higher risk of developing dementia and a 23% increase in cognitive decline compared to those with more stable levels.
The study specifically tracked both “bad” cholesterol (LDL) and “good” cholesterol (HDL). Like a detective story, the researchers discovered that fluctuations in total cholesterol and LDL cholesterol were the primary villains, associated with faster declines in memory, reaction speed, and overall cognitive health. Interestingly, changes in “good” cholesterol or triglycerides (the most common type of fat in your body) didn’t show the same concerning connection to brain health.
But what might explain this connection? Dr. Zhou offers one possible explanation: “Significant fluctuations in total and LDL cholesterol levels may destabilize atherosclerotic plaques, which are mostly composed of LDL cholesterol. This destabilization can raise the risk of plaque growth, rupture and subsequent obstruction of blood flow in the brain, which may therefore impact brain function.”
The findings emerge from a broader research project called ASPREE (ASPirin in Reducing Events in the Elderly), which originally set out to study aspirin’s effects on heart disease risk in older adults. The researchers cleverly used this existing data to explore the cholesterol-cognition connection, following participants for nearly six years after their initial cholesterol measurements.
The stakes couldn’t be higher. According to recent CDC projections, the number of American adults aged 65 and older with dementia is expected to nearly double from 7 million in 2014 to 14 million by 2060. Meanwhile, current data shows that over 63 million American adults – about one in four – have high levels of “bad” cholesterol.
“In the past, studies have focused on the connection between individual vascular risk factors and cognitive decline,” Dr. Fernando D. Testai, a professor of neurology at the University of Illinois Chicago and American Heart Association volunteer expert, puts these findings in perspective. “However, there is evidence that an increase in the variability of certain functions in the body, such as blood pressure or blood sugar levels, can be harmful to both the heart and the brain.”
The research team emphasizes that these findings shouldn’t discourage people from taking steps to lower their cholesterol through medication or lifestyle changes. Rather, it suggests that maintaining consistent levels through steady habits might be key to protecting both heart and brain health.
After all, when it comes to cholesterol and brain health, it seems that steadiness wins the race.
Paper Summary
Methodology
The study examined 9,846 participants, mostly from Australia (87%) with some from the U.S. (13%), who were enrolled in the ASPREE trial between 2010 and 2014. These participants, averaging 74 years old, underwent annual cholesterol measurements for three years. About one-third were taking cholesterol-lowering medications, but importantly, anyone who changed their medication during the study was excluded to ensure the results weren’t skewed. The researchers used these three years of measurements to calculate how much each person’s cholesterol levels varied, then followed the participants for about six years to see who developed cognitive problems.
Results
During the follow-up period, 509 participants developed dementia, while 1,760 showed signs of cognitive decline without full dementia. The study found that people with the highest cholesterol fluctuations (top 25%) had significantly higher risks of both conditions. Specifically, they showed faster declines in memory tests and reaction speed compared to those with more stable levels. Notably, only variations in total and LDL cholesterol showed this connection – changes in HDL and triglycerides didn’t appear to affect cognitive health.
Limitations
The research team acknowledges several important limitations. First, cholesterol readings can vary for many reasons that weren’t analyzed in this study, which could affect the results. Additionally, since 96% of participants were white adults, the findings might not apply equally to other demographic groups. As an observational study, it can’t prove that cholesterol fluctuations directly cause dementia – only that there’s a correlation between the two.
Discussion and Key Takeaways
The research suggests a potential new way to identify people at risk for cognitive decline – by monitoring not just their cholesterol levels, but how stable those levels remain over time. This could lead to earlier interventions and better prevention strategies. The study also reinforces the importance of consistent heart-healthy habits, as they might help maintain more stable cholesterol levels. However, the researchers emphasize that these findings shouldn’t discourage people from working to lower their cholesterol through medication or lifestyle changes.
Funding and Disclosures
This information was presented at the American Heart Association’s Scientific Sessions 2024, with the study’s co-authors, disclosures, and funding sources listed in the abstract. The findings are considered preliminary until published in a peer-reviewed journal. The American Heart Association notes that while it receives funding from various sources, including pharmaceutical and biotech companies, it maintains strict policies to prevent these relationships from influencing scientific content.
