High cholesterol may increase the risk of Alzheimer’s disease: Study

While most people are aware that high cholesterol is a major health issue that can increase the risk of stroke, peripheral arterial disease, coronary artery disease and cardiovascular disease, new research shows that there may also a link between high LDL cholesterol levels and early-onset Alzheimer’s disease.

Everyone naturally has high-density lipoprotein (good cholesterol) and low-density lipoprotein (bad cholesterol) in their bodies, but researchers are now interested in how LDL cholesterol can impact the development of the early-onset of Alzheimer’s. Higher levels of high-density lipoprotein are actually good for health, but the body’s cells can’t handle high levels of LDL.

Cholesterol can build up in the walls of the arteries when levels are too high, leading to an array of serious health problems.

“The big question is whether there is a causal link between cholesterol levels in the blood and Alzheimer’s disease risk,” lead author Thomas Wingo said in the study published in the JAMA Neurology Journal.

While previous data has been inconclusive, researchers believe one interpretation of the new study is that LDL plays a casual role when a person develops Alzheimer’s disease.

“If that is the case, we might need to revise targets for LDC cholesterol to help reduce Alzheimer’s risk,” Wingo said. “Our work now is focused on testing whether there is a causal link.”

Higher cholesterol levels have been linked to an increased risk of Alzheimer’s in later life, but little research exists about the possible connection between cholesterol levels and the risk of early-onset Alzheimer’s – which typically appears in people aged 65 and younger.

Read more: Australians forking out $100M on high cholesterol medication

Early-onset Alzheimer’s makes up around 10 per cent of all Alzheimer’s cases, with most of those affected inheriting genes from their parents. A mutation in a gene called APOE is the largest known single genetic risk factor for Alzheimer’s disease, while a variation called APOE E4 is known to raise levels of circulating cholesterol.

Researchers analysed 2,125 people as part of their study. Of those, 654 had early-onset Alzheimer’s and 1,471 were controls. Blood samples of 267 participants were also analysed to measure the amount of LDL cholesterol.

It was found that APOE E4 explained 10 per cent of cases of early-onset Alzheimer’s, while one of three other specific gene variants related to early-onset Alzheimer’s (APP, PSEN1 and PSEN2) were identified in 3 per cent of cases.

After analysing blood samples, participants with elevated LDL levels were more likely to have early-onset Alzheimer’s disease, compared with patients with lower cholesterol levels. There was no link found between high-density lipoprotein levels and early-onset Alzheimer’s.

The study also found that a rare variant of a gene called APOB – a gene that encodes a protein that’s involved in the metabolism of lipids, or fats, including cholesterol – was another possible genetic risk factor for early-onset Alzheimer’s.

Read more: High Cholesterol: Signs, symptoms and when to talk to a health professional

Patients with high cholesterol are often prescribed statins or cholesterol-lowering medication to manage the condition, while diet and lifestyle changes can reduce levels in those without a genetic version of the disease.

Decreasing red meat consumption and increasing levels of plant-based foods, nuts, walnuts, almonds and pecans can help, while physical exercise also plays a role in lowering LDL levels.

It’s always important to talk to a doctor about the right treatment for you.

Do you think high cholesterol can increase the risk of dementia? How do you manage your cholesterol levels?