Older people whose cholesterol readings show big changes from one year to the next may be at an increased risk of cognitive problems as they age, including dementia.

Those whose cholesterol levels changed the most over the course of three annual tests had up to a 60% increased risk of being diagnosed with dementia within the next six years, and a 23% increased risk of cognitive decline, according to early findings that will be presented at the American Heart Association Scientific Sessions 2024 conference in Chicago.

“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,” researcher Zhen Zhou, PhD, a postdoctoral research fellow in the School of Public Health and Preventive Medicine at Monash University in Melbourne, Australia, said in a news release.

The analysis, which included 9,846 people, focused on older adults. Everyone in the study was in their 70s, and 55% were women. Nearly all of them lived in Australia and were White, and about 40% were past smokers. More than half of the people had overweight or obesity, and about 1 in 4 reported a family history of dementia. People who started or stopped cholesterol medications, like a statin, were excluded from the data because the researchers didn’t want changes in treatment to impact the results.

The cholesterol levels of people in the study were checked annually for three years, and afterward they were tracked for another six years. During that time, 509 people got dementia and 1,760 were diagnosed with cognitive decline — a decline in mental skills like thinking, remembering, and learning. They took tests to determine cognitive decline or dementia onset that evaluated abilities such as memory, reaction speed, and word recall.

Changes in total cholesterol and low-density-lipoprotein cholesterol (LDL-C) were both linked to a higher risk of dementia and faster cognitive decline, but the researchers reported “no strong evidence” linking those problems to variability of high-density-lipoprotein cholesterol (HDL-C) or triglycerides.

About 1 in 4 adults in the U.S. have high LDL, or “bad,” cholesterol levels (130 mg/dL or higher), according to the American Heart Association. Variability in important health metrics is already well-known to be a sign of potential health problems, noted Fernando D. Testai, MD, PhD, a professor of neurology and rehabilitation at the University of Illinois Chicago, who wasn’t involved in the research. He pointed to examples of blood pressure and blood sugar variation being linked to the risk of heart disease and stroke.