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) ε4 allele. Studies of SMI have been predominantly confined to white Caucasian
Method. 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 ε4 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 ε4 and SMI increased as MMSE
scores decreased and was particularly strong in those with depression. The ε4 allele was present in
69% (95% CI 41–89%) of those with depression and SMI compared with 28% (20–36%) of those
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 ε4 and
therefore, presumably, a raised risk of subsequent dementia.