While this finding could reflect a protective effect of a higher 24‐OHC/27‐OHC ratio against dementia among APOE2+ carriers, the consistent reports of the deleterious effects of altered oxysterol levels6, 7, 8, 9, 10, 16, 17, 21, 22, 23, 24 suggest a greater likelihood that APOE ε2 allele may instead be protective against pathological effects of abnormal oxysterol levels. This evidence concerns the gene APOE and dementia.