Abstract
Several studies have reported an association between the ApolipoproteinE-ɛ4 (APOE4) allele and depression among elders. However others have failed to find an association. Since APOE4 is a well recognized risk factor for Alzheimer dementia, cognitive status may represent an important confounder between APOE4 and depression. In this investigation, we examined the relationship between the ApolipoproteinE-ɛ4 allele and depression among elders accounting for cognitive status. Using a case-control design (
n
=
1052), we investigated the association between ApolipoproteinE-ɛ4 and depression in Alzheimer disease patients (
n
=
528) and in cognitively intact controls (
n
=
524). We demonstrated an apparent association between the APOE4 allele and depression in the combined dataset (
p
=
0.001) when not controlling for cognitive status. However, once stratified by the presence of Alzheimer disease, there was no association in either the Alzheimer group (
p
=
0.290) or the cognitively intact controls (
p
=
0.494). In this dataset there is no association between the ApolipoproteinE-ɛ4 allele and depression among those with Alzheimer disease or among cognitively intact elders. However there is a significant association between female gender and depression in the cognitively intact (
p
=
0.003) but not among those with Alzheimer disease. Additionally, individuals with Alzheimer disease and depression had a significantly younger age of onset for their Alzheimer disease than those without depression (
p
=
0.017).
