High cholesterol has been associated with several health issues, including the risk of developing hypertension and heart diseases. But can fluctuating cholesterol levels also pose health risks? A recent study has found that a decrease or increase in lipid levels can raise dementia risk in the elderly.

Previous studies showed that abnormally high levels of lipids in the blood were associated with Alzheimer's and other dementias. In the latest study published in the journal Neurology, researchers from Mayo Clinic, Minnesota, evaluated the impact of lipid variability - the changes, both increase or decrease in lipid levels – on Alzheimer's and related dementias. Researchers also took into account how the risk of dementia differs among specific types of cholesterol.

For the study, researchers used the healthcare data from 11,571 people who were not previously diagnosed with Alzheimer's disease or dementia. All the participants were of age 60 or above.

The lipid profiles of the participants, including total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL) and high-density lipoprotein cholesterol (HDL) were taken at least three different days in the five years before the start of the study.

They were divided into five groups based on the level of lipid fluctuations and were followed up for an average of 13 years. During the study, 2,473 participants developed Alzheimer's disease or another form of dementia.

Participants in the group with the highest fluctuation of total cholesterol had a 19% increased risk of dementia compared to the group with the lowest level of fluctuations. Also, there was a 23% increased risk for the participants with the highest level of fluctuation in triglycerides. The study does not suggest any link between variations in LDL and HDL and higher dementia risk.

"Routine screenings for cholesterol and triglyceride levels are commonly done as part of standard medical care. Fluctuations in these results over time could potentially help us identify who is at greater risk for dementia, help us understand mechanisms for the development of dementia and ultimately determine whether leveling out these fluctuations could play a role in reducing dementia risk," study author Suzette J. Bielinski said.

However, researchers could not determine why the levels of cholesterol and triglycerides are related to the risk of Alzheimer's disease.

"This study adds to a growing body of evidence showing that addressing certain modifiable risk factors and promoting healthy behaviors can reduce the risk of cognitive decline, possibly reduce the risk of dementia, and protect cognitive health," Christopher Weber, director of global science initiatives at the Alzheimer's Association, told CNN. Weber was not involved in the study.