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Low LDL cholesterol levels may reduce risk of Alzheimer’s disease

Latest research from the nursing and medical journals.

Latest research from the nursing and medical journals.

Statins are cholesterol-lowering drugs. Picture: iStock

Patients at high risk of cardiovascular disease are recommended to reduce their low-density lipoprotein (LDL) levels to less than 2.6mmol/L, while those at very high risk are advised to reduce levels to less than 1.8mmol/L.

However, cholesterol is a major constituent of the brain, especially the myelin encircling neurons. Some research suggests that the risk of neurological diseases, such as Alzheimer’s disease and Parkinson’s disease, increases in people treated with cholesterol-lowering drugs such as statins.

This article suggests that such research may suggest an increased risk because people change their lifestyle after neurological problems develop so that a decrease in LDL levels is a result, not a cause, of neurological changes.

The authors studied people with a genetic predisposition to low cholesterol to see if they had higher levels of Alzheimer’s disease, vascular dementia or other type of dementia or Parkinson’s disease. The advantage of studying this group, rather than those using cholesterol-lowering drugs such as statins, is that they will have had a lifelong low LDL level.

The reassuring findings are that there is no evidence of an increase in the risk of developing dementia or Parkinson’s disease in people with genetically low LDL cholesterol levels. There is even a suggestion that having genetically low LDL cholesterol levels may reduce the risk of Alzheimer’s disease.

Further studies are needed to see if using lipid-lowering drugs, such as statins, can provide the same beneficial outcome.

Benn M, Nordestgaard B, Frikke-Schmidt R et al (2017) Low LDL cholesterol, PCSK9 and HMGCR genetic variation, and risk of Alzheimer’s disease and Parkinson’s disease: Mendelian randomisation study. BMJ. 357:j1648.

Compiled by Ruth Sander, independent consultant in care of the older person

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