Are cognitively intact seniors with subjective memory loss more likely to develop dementia?

BACKGROUND: Subjective memory loss (SML) is common in elderly persons. It is not clear if SML predicts the development of dementia.

OBJECTIVES: (1) to determine if SML in those with normal cognition predicts dementia or cognitive impairment without dementia (CIND); (2) to determine if an association is independent of the effect of age, gender and depressive symptoms.

METHODS: Secondary analysis of the Manitoba Study of Health and Aging (MSHA), a population-based prospective study. Data were collected in 1991, and follow-up was done 5 years later. Community-dwelling seniors sampled randomly from a population-based registry in the Canadian province of Manitoba, stratified on age and region. Only those scoring in the normal range of the Modified mini-mental state examination (3MS) were included. Predictor variables were self-reported memory loss, 3MS, Center for epidemiological studies-depression scale (CES-D), age, gender, and education. Outcomes were mortality and cognitive impairment five years later.

RESULTS: In bivariate analyses, SML was associated with both death and dementia. In multivariate models, SML did not predict mortality. After adjusting for age, gender, and depressive symptoms, SML predicted dementia. However, after adjusting for baseline 3MS score, SML did not predict dementia.

CONCLUSIONS: Memory complaints predict the development of dementia over five years, and clinicians should monitor these persons closely. However, the proportion of persons developing dementia was small, and SML alone is unlikely to be a useful clinical predictor of dementia.