We observed overall lower LCAT activity in APOE3E4 vs. APOE3E3 carriers; thus, the lack of difference in LCAT activity among the APOE3E4 carriers may be due to the fact that all individuals who are carriers of APOE4 may already have diminished LCAT activity compared to non-APOE4 carriers, and this reduction is not further enhanced in patients with dementia compared to the controls. Here, LCAT is linked to dementia.