US researchers have reported that high levels of bad cholesterol and low levels of good cholesterol are associated with greater amounts of the Alzheimer’s protein, amyloid, in the brain in a group of people at high cardiovascular risk. The findings are published on 30 December 2013 in the journal JAMA Neurology.
The team studied 74 people with an average age of 78, who were at higher risk of cardiovascular disease. Three of the volunteers had mild dementia, 38 had an early stage memory and thinking problems – called mild cognitive impairment – and the rest had no memory and thinking problems.
Levels of ‘bad’ cholesterol (called LDL) and ‘good’ cholesterol (called HDL) were measured in the blood of the volunteers, who also underwent brain scans to measure levels of amyloid in the brain. The build-up of amyloid in the brain is a key feature of Alzheimer’s disease, but the protein can also be detected in the brains of people without any cognitive impairment.
The team found that higher levels of LDL and lower levels of HDL were associated with higher levels of amyloid in the brain. Total cholesterol levels were not associated with the amount of amyloid in the brain. The study did not follow the volunteers to see whether those with higher amyloid went on to develop Alzheimer’s disease at a later date.
Dr Laura Phipps of Alzheimer’s Research UK, said:
“This study found an association between high cholesterol and levels of amyloid in the brain – which can be an early indicator of Alzheimer’s. While this study did not investigate the mechanism behind the link, the findings add to existing evidence that cholesterol could play a role in the Alzheimer’s disease process. Despite this, clinical trials carried out to date have not provided evidence to recommend cholesterol-lowering statin treatment as a way to treat or prevent Alzheimer’s.
“This study adds to previous research suggesting that a healthy lifestyle in midlife could have benefits for our cognitive health into older age. Current evidence suggests the best way to keep our brain healthy is to eat a balanced diet, maintain a healthy weight, not smoke, exercise regularly and keep blood pressure and cholesterol in check. Anyone who has concerns about their cholesterol levels should talk to their GP.”