Fluctuating Cholesterol Levels May Signal Increased Dementia Risk in Older Adults

Recent research presented at the American Heart Association's Scientific Sessions 2024 indicates that unexplained fluctuations in cholesterol levels may serve as an early warning sign for dementia risk in older adults. The study, which analyzed data from nearly 10,000 participants in their 70s over a six-year period, found that those with stable cholesterol levels had a significantly lower risk of developing dementia or experiencing cognitive decline compared to individuals with fluctuating levels.

Lead author Zhen Zhou, Ph.D., a postdoctoral research fellow at Monash University in Melbourne, Australia, emphasized the importance of these findings, stating, '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.'

The study utilized data from the ASPirin in Reducing Events in the Elderly (ASPREE) clinical trial, focusing on participants who did not start, stop, or change lipid-lowering medication during the follow-up period. Researchers analyzed the first three annual cholesterol measurements to determine the variability in each participant's lipid levels.

The results were striking. Compared to those with the most stable cholesterol levels, individuals with high fluctuations in total cholesterol (in the top 25%) showed a 60% increase in dementia risk and a 23% increase in cognitive decline. Furthermore, fluctuations in LDL cholesterol were associated with faster declines in overall cognitive health, memory, and reaction speed.

While the study cannot prove a direct cause-and-effect relationship, it raises important questions about the potential link between cholesterol variability and brain health. Zhou suggested that significant fluctuations in total and LDL cholesterol levels might destabilize atherosclerotic plaques, potentially increasing the risk of blood flow obstruction in the brain and impacting cognitive function.

The implications of this research are significant for public health, particularly given the projected increase in dementia cases. The U.S. Centers for Disease Control and Prevention estimates that the number of adults aged 65 and older with dementia could nearly double from 7 million in 2014 to 14 million by 2060.

Fernando D. Testai M.D., Ph.D., FAHA, a professor of neurology and rehabilitation at the University of Illinois Chicago and American Heart Association volunteer expert, commented on the study's importance: 'This study adds an important piece to the puzzle of preserving brain health by providing evidence that increasing variability in cholesterol levels is associated with cognitive decline.'

While the study has limitations, including potential variability in cholesterol readings due to unanalyzed factors and a predominantly white participant pool, it opens new avenues for research and potential interventions. If future studies confirm a causal relationship, reducing cholesterol variability could become a promising therapeutic target for dementia prevention.

The findings underscore the importance of regular cholesterol monitoring in older adults and highlight the potential for using cholesterol variability as a biomarker for dementia risk. This could lead to earlier interventions and more targeted preventive strategies for at-risk individuals.

As the global population ages and dementia rates continue to rise, this research provides valuable insights that could shape future approaches to cognitive health in older adults. It emphasizes the need for consistent health management and the potential benefits of maintaining stable cholesterol levels throughout later life.