The influence of vascular disease on cognitive performance in the preclinical and early phases of Alzheimer's disease.

BACKGROUND/AIM: Alzheimer's disease (AD) is one of the most important causes of old-age cognitive impairment. We aimed to examine the influence of history of vascular disease on cognition in preclinical and early AD.

METHODS

Participants from a population-based study were assessed twice with a test of global cognition. The study sample was nondemented at baseline. Three years later, 138 persons were diagnosed with AD and 783 persons remained nondemented. History of vascular disease (heart disease, cerebrovascular disease) was assessed at both occasions.

RESULTS

Analyses of covariance revealed significant main effects of group (AD; comparison group) and vascular disease (present; absent) at baseline and follow-up (p < 0.01). At follow-up, a significant interaction indicated that the AD group was more negatively affected by vascular disease (p < 0.01). The fastest rate of cognitive decline was observed for those persons with preclinical AD who had new recordings of vascular disease.

CONCLUSIONS

History of vascular disease has a negative impact on cognition in old age. This effect is most pronounced in persons in the earliest clinical phases of AD. Treatment of vascular risk factors in early AD might postpone time of diagnosis and slow down dementia progression.