Plasma Total Cholesterol Level as a Risk Factor for Alzheimer Disease

Abstract
THE APOLIPOPROTEIN E (APOE) ϵ4 allele is a cholesterol transport protein that is a well-established risk factor for late-onset Alzheimer disease (AD).1 The presence of an APOE ϵ4 allele increases the lifetime risk for development of AD and is also associated with an earlier age of onset. However, it is an incomplete predictor of disease susceptibility, as AD does not develop in all subjects with the APOE ϵ4 allele and not all patients with AD have the ϵ4 allele.