Terminal decline and markers of cerebro- and cardiovascular disease: findings from a longitudinal study of the oldest old.

The purpose of this study was to examine the cognition-survival relationship among nondemented individuals in late life. The longitudinal design included three examinations at 2-year intervals. At baseline, 466 individuals (age range = 80-98) were examined. During the 6 years of follow-up, 206 individuals died. Four survival groups were defined on the basis of mortality prior to the subsequent measurement occasion. Tests of cognitive functioning encompassed the domains of crystallized knowledge, inductive reasoning, visuospatial ability, short-term memory, episodic memory, and speed. Significant associations were found between cognitive performance at baseline and subsequent survival. After adjusting for stroke and markers of cardiovascular disease, the authors found that only three out of six cognitive domains remained significant predictors of survival. The longitudinal analyses revealed limited evidence for an accelerated decline prior to death. The main results suggest that level of cognitive performance in late life is associated with proximity to death, that this relationship is longstanding, and that it is partially influenced by compromised cardio- and cerebrovascular functioning.