New Study: Cholesterol May Affect Dementia Risk by Up to 60%

It’s well demonstrated that having consistently high cholesterol can lead to a range more health problems, with heart attack and stroke being two important examples. However, a new study has made a surprising discovery: Having significant fluctuations in your cholesterol values may also contribute to dementia risk.

A team of 20 researchers joined forces from the USA, Germany, Australia, and China on a study published in January 2025 in the medical journal Neurology. Specializing in fields such as diabetes, geriatrics, and public health, the researchers assessed the medical data of nearly 10,000 participants enrolled in a randomized clinical trial known as ASPirin in Reducing Events in the Elderly (ASPREE).

Collected over a period of three years, the research initially aimed to determine whether low-dose aspirin was effective for reducing heart disease risk in Australian and American adults aged 65 and older. The patients’ lipid levels were collected annually during that time, in order to compare year-over-year variability in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), and triglycerides.

As part of their post-hoc analysis, after the third year the team then analyzed data from cognitive tests performed that probed global cognition, memory, processing speed, verbal fluency, and more. Following up over an additional period of five years, the researchers looked for associations between cholesterol levels and dementia, as well as mild cognitive impairment without dementia.

They discovered that participants with the greatest year-to-year changes in lipid levels had a 60% increased risk of dementia, compared with those with the lowest levels of fluctuation. They also noted a 23% increase in risk of mild cognitive impairment among that group.

The researchers note that dyslipidemia, or having abnormal levels of fat in the bloodstream, is a known risk factor for cognitive decline. However, they say that most previous studies “used cholesterol values measured at a single time point, which fails to account for what the level was in the past and fluctuations over time.” They add that monitoring cholesterol fluctuations could be particularly useful in older people, who may be uniquely affected by “biological aging, functional decline, reduced physiologic reserve, and nutrient intake.”

According to the Cleveland Clinic, the ideal cholesterol levels for adults—measured in milligrams of cholesterol per deciliter of blood (mg/dL)—are as follow:

• HDL or “good” cholesterol: Above 60 mg/dL
• LDL or “bad” cholesterol: Below 100 mg/dL
• Total cholesterol: Below 200 mg/dL

The Mayo Clinic says though medication is sometimes necessary to prevent fluctuations or spikes in cholesterol levels, there are ways to maintain healthy numbers over time using simple lifestyle interventions. First and foremost, it’s important to follow a balanced diet that’s low in saturated and trans fats and high in soluble fiber, omega-3 fatty acids, and lean protein—plant-based as often as possible. It’s also important to exercise regularly, limit your alcohol intake, maintain a healthy body weight, and quit smoking if you count that as a habit.

Additionally, it’s a good idea to discuss regular cholesterol screenings when you go to your doctor for a check-up—maybe now, not just “How are my numbers?” but also, “How are they comparing to the past few years?” Lead researcher Zhen Zhou, a fellow at Monash University in Australia, said in a news release: “Fluctuating cholesterol, measured annually, may be a new biomarker for identifying people at risk of dementia, providing more information than the actual cholesterol levels measured at a single time point.”

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