A University of Bristol-led study analyzing data from over one million people in Denmark, England, and Finland has found that naturally lower cholesterol levels are associated with a reduced risk of dementia. Using a technique called Mendelian randomization, researchers examined individuals with genetic variants that mimic the effects of cholesterol-lowering drugs like statins and ezetimibe, comparing them to those without these variants. The study found that reducing blood cholesterol by one millimole per liter was associated with up to an 80% reduction in dementia risk for certain drug targets.
Based on these findings, researchers hypothesize that high cholesterol may increase dementia risk through atherosclerosis, which causes cholesterol accumulation in blood vessels and can lead to small blood clots in the brain. While the findings suggest a strong link between low cholesterol and reduced dementia risk, the researchers emphasize that long-term randomized clinical trials are needed to definitively establish the protective effects of cholesterol-lowering medications.