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OBJECTIVES: To examine the association between self-reported memory failures and incident dementia in individuals aged 60 and older.

DESIGN: Longitudinal, community based.

SETTING: Betula Prospective Cohort Study, a population-based study in Umea, Sweden.

PARTICIPANTS: Individuals with a mean age of 71.5 +/- 8.8 (range 60-90) (N = 1,547).

MEASUREMENTS: Participants rated the frequency of everyday memory failures using the 16-item Prospective and Retrospective Memory Questionnaire (PRMQ) and underwent objective memory testing at baseline. Participant self-reports of complaints of poor memory by family and friends were evaluated. Dementia status was followed-up for 10 to 12 years.

RESULTS: Over the study period, 225 participants developed dementia (132 with Alzheimer's disease (AD)). In Cox proportional hazard regression models adjusted for demographic factors, PRMQ z-scores predicted incident dementia (hazard ratio (HR) = 1.21 for all-cause dementia; HR = 1.25 for AD, Ps < .01). The significant associations remained when depressive symptoms and objective memory performance were adjusted for, when low performers on objective memory (= 1 standard deviations below the age group mean) were excluded, and in analyses with delayed entry (survival time = 5 years). Similar patterns were observed for the prospective and retrospective subscales, although including how often participants self-reported that others complained about their poor memory eliminated the association between PRMQ scores and dementia and itself emerged as a significant predictor.

CONCLUSION: Self-reported memory failure predicted future dementia or AD independent of objective memory performance. Subjective reports of complaints by family and friends appear to be an even more-important indicator of preclinical impairments, and physicians should not ignore them, even in the absence of objective memory deficits.