Depression, APOE genotype and subjective memory impairment: a cross-sectional study in an African-Caribbean population.
BACKGROUND
Subjective memory impairment (SMI) is common in older populations but its aetiology and clinical significance is uncertain. Depression has been reported to be strongly associated with SMI. Associations with objective cognitive impairment are less clear cut. Other factors suggested to be associated with SMI include poor physical health and the apolipoprotein E (APOE) epsilon4 allele. Studies of SMI have been predominantly confined to white Caucasian populations.


METHODS
A community study was carried out in a UK African-Caribbean population aged 55-75, sampled from primary care lists. Twenty-three per cent were classified with SMI. Depression was defined using the 10-item Geriatric Depression Scale. Other aetiological factors investigated were education, objective cognitive function, APOE genotype, disablement and vascular disease/risk. The principal analysis was restricted to 243 participants scoring > 20 on the Mini-Mental State Examination (85%). A second analysis included all 290 participants.


RESULTS
Depression, self-reported physical impairment and APOE epsilon4 were associated with SMI. The association between SMI and physical impairment was not explained by depression, vascular disease/risk, or disability/handicap. The association between epsilon4 and SMI increased as MMSE scores decreased and was particularly strong in those with depression. The epsilon4 allele was present in 69% (95% CI 41-89%) of those with depression and SMI compared with 28% (20-36%) of those with neither.


CONCLUSIONS
Depression may not be a sufficient explanation for subjective memory complaints. Memory complaints in the presence of depression are associated with high prevalence of epsilon4 and therefore, presumably, a raised risk of subsequent dementia.
Stewart
R
R
Section of Old Age Psychiatry, Institute of Psychiatry, London.
Russ
C
C
Richards
M
M
Brayne
C
C
Lovestone
S
S
Mann
A
A
D000368:Aged; D000483:Alleles; D001057:Apolipoproteins E / Q000235:genetics*; D044383:Black People; D017691:Caribbean Region / Q000208:ethnology; D003072:Cognition Disorders / Q000175:diagnosis / Q000208:ethnology / Q000209:etiology; D003430:Cross-Sectional Studies; D003863:Depression / Q000208:ethnology* / Q000235:genetics* / Q000523:psychology; D005260:Female; D005838:Genotype; D006304:Health Status; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000208:ethnology* / Q000209:etiology / Q000235:genetics*; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D006113:United Kingdom / Q000453:epidemiology
D001057:Apolipoproteins E