Objectives: To explore whether more cognitive complaints are associated with previous or future cognitive decline.
Design: Longitudinal; epidemiology vascular aging study.
Setting: Community in Nantes, France.
Participants: Seven hundred thirty-three subjects, aged 59 to 71.
Measurements: Subjective cognitive complaints were recorded at 4-year follow-up examination in a prospective study of people aged 59 to 71 at study entry. Participants' cognitive performances were assessed repeatedly at each wave (baseline, 4 years, and 6 years) of the study using a series of neuropsychological tests including the Mini-Mental State Examination. Depressive symptoms were evaluated using the Center for Epidemiological Studies Depression Scale. Subjects also had a cerebral magnetic resonance imaging scan at 4-year follow-up to evaluate presence and severity of white matter hyperintensities (WMHs).
Results: Subjects with more cognitive complaints had greater cognitive decline. This significant relationship persisted after adjusting for potential confounders, including depressive symptoms. Multivariate analysis also showed that, in subjects without measured cognitive decline between study entry and 4-year follow-up, those with more cognitive complaints at 4-year follow-up had significantly greater measured cognitive decline during the subsequent 2 years. In the presence of severe WMH, more cognitive complaints were an even stronger predictor of future cognitive decline.
Conclusion: Cognitive complaints reflect measured cognitive decline, but they also predict cognitive decline at an earlier stage than objective tests that are not able to detect cognitive deficits. They need to be taken into account in clinical practice.