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.

The research, led by Zhen Zhou, Ph.D., a postdoctoral research fellow at Monash University in Melbourne, Australia, utilized data from the ASPirin in Reducing Events in the Elderly (ASPREE) clinical trial. Participants, who were all relatively healthy adults without dementia at the start of the study, had their cholesterol levels monitored annually. The study excluded individuals who started, stopped, or changed lipid-lowering medications during the follow-up period to isolate the effects of natural cholesterol fluctuations.

Results showed that high fluctuations in total cholesterol were associated with a 60% increase in dementia risk and a 23% increase in cognitive decline. Additionally, variations in low-density lipoprotein (LDL) cholesterol were linked to faster declines in overall cognitive health, memory, and reaction speed. Interestingly, fluctuations in high-density lipoprotein (HDL) cholesterol and triglycerides did not show a significant association with dementia or cognitive decline.

The implications of these findings are significant for both medical professionals and the aging population. As the number of adults aged 65 and older with dementia is projected to nearly double from 7 million in 2014 to 14 million by 2060, according to the U.S. Centers for Disease Control and Prevention, early identification of risk factors becomes crucial. This study suggests that routine cholesterol screenings could potentially be used to identify individuals at higher risk of developing dementia, allowing for earlier intervention and prevention strategies.

However, the researchers caution that the study has limitations. The participant pool was predominantly white (96%), which may limit the generalizability of the findings to other population groups. Additionally, as an observational study, it cannot establish a definitive cause-and-effect relationship between cholesterol fluctuations and dementia risk.

Dr. Zhou emphasized that these results should not be interpreted as suggesting that lowering cholesterol through lifestyle modifications or medications is harmful to brain health. Instead, the findings highlight the potential importance of maintaining stable cholesterol levels over time.

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, noted that this study adds an important piece to the puzzle of preserving brain health. He pointed out that increasing variability in various bodily functions, including blood pressure and blood sugar levels, can be harmful to both the heart and brain.

The study's findings open up new avenues for research into the relationship between cholesterol variability and dementia risk. Future studies may help determine whether cholesterol fluctuations are a risk factor, precursor, or biomarker of dementia. One possible explanation proposed by the researchers is that significant fluctuations in total and LDL cholesterol levels may destabilize atherosclerotic plaques, potentially leading to obstructed blood flow in the brain and impacting brain function.

As the global population ages and dementia rates are expected to rise, this research provides valuable insights that could inform future diagnostic and preventive strategies. By potentially identifying at-risk individuals earlier through routine cholesterol monitoring, healthcare providers may be able to implement more targeted interventions to maintain cognitive health in older adults. This study underscores the importance of consistent health monitoring and the potential for seemingly unrelated health markers to provide crucial information about cognitive health risks.