Background and purpose: Recent studies have shown that cognitive deficits are present during the years preceding a diagnosis of vascular dementia (VaD). The aims of this study were to (1) extend previous research by examining whether cognitive deficits are already present 6 years before diagnosis, and (2) examine the strength of the association between cognitive performance and a future VaD diagnosis after controlling for previous vascular disorders.
Methods: Subjects from a population-based study of very old persons (> or =75) were examined with a test of global cognitive functioning (the Mini-Mental State Examination [MMSE]) at 3 occasions over a 6-year period. The study sample was nondemented the first 2 measurement times. On the last occasion, 22 individuals were diagnosed with VaD, and 450 persons remained nondemented.
Results: The preclinical VaD group showed no MMSE deficits 6 years before diagnosis (P>0.10) compared with the controls. However, 3 years before diagnosis, poor cognitive performance was significantly associated with forthcoming VaD after controlling for demographic factors and prior vascular disorders (odds ratio, 2.55; 95% CI, 1.67 to 3.89).
Conclusions: This study extends previous findings on preclinical cognitive deficits in VaD and suggests that cognitive measures can be useful in the process of recognizing individuals at risk for developing VaD to initiate early treatment.