A recent study suggests that older adults experiencing fluctuations in cholesterol levels over time may have a greater risk of developing dementia compared to those with stable cholesterol levels, regardless of their actual cholesterol numbers. This research is featured in the January 29, 2025, online edition of Neurology®, the journal of the American Academy of Neurology.
The research does not establish that changing cholesterol directly causes dementia, but it indicates a correlation between the two.
According to study author Dr. Zhen Zhou from Monash University in Melbourne, Australia, “The findings imply that variations in cholesterol levels, measured on an annual basis, might serve as a new indicator for identifying individuals at risk for dementia. This could provide more helpful insights than single-time cholesterol level readings.”
The study involved a total of 9,846 participants with an average age of 74 who were free from dementia and memory-related issues. Cholesterol was assessed at the start of the study and during three subsequent annual check-ups. Participants were observed for about 5.5 years following their third check-up, during which they completed yearly memory tests.
Participants who were on cholesterol-lowering medications, known as statins, were included in the study as long as they did not change their medication regimen during the cholesterol measurement period.
Subjects were split into four groups based on the degree of change in their cholesterol levels from the first to the fourth measurement. The group with the greatest change in total cholesterol experienced an average difference of 91 mg/dL, while the group with the least change saw an average difference of 22 mg/dL.
Throughout the research, 509 participants were diagnosed with dementia. Specifically, among the 2,408 individuals in the group with the highest cholesterol fluctuations, 147 developed dementia, resulting in a rate of 11.3 cases per 1,000 person-years. In contrast, 98 out of 2,437 individuals in the group with the smallest changes were found to have dementia, equating to a rate of 7.1 per 1,000 person-years. The term “person-years” refers to both the number of participants and the total duration each individual was part of the study.
After taking into account other factors that could influence dementia risk, including age, smoking habits, and high blood pressure, researchers found that individuals with significant cholesterol fluctuations were 60% more likely to develop dementia compared to those with stable cholesterol levels.
Additionally, the study identified a connection between variable cholesterol levels and cognitive decline or memory issues that did not qualify as dementia.
When examining different cholesterol types, researchers discovered that fluctuating levels of LDL cholesterol, often referred to as “bad” cholesterol, were linked to increased risks of dementia and cognitive impairment. However, no such association was found for HDL cholesterol (the “good” cholesterol) or triglycerides.
Dr. Zhou stated, “It’s crucial for older adults to have their cholesterol monitored periodically for changes, as this could help identify those at risk of cognitive decline or dementia. Such individuals might benefit from preventive measures, which could include lifestyle modifications or ensuring the continuation of statin use to stabilize cholesterol levels and potentially lower dementia risk.”
A limitation of the study is that while participants who altered their cholesterol medication were excluded to avoid inconsistencies in cholesterol levels, the researchers lacked data on dosage changes or whether participants adhered to their prescribed medication, factors that could influence cholesterol variations.
This research received support from the National Heart Foundation of Australia.
