Relation between cognitive function and mortality in middle-aged adults: the atherosclerosis risk in communities study.
An independent, inverse association between cognitive function and all-cause mortality has been reported in elderly cohorts. The purpose of this study was to determine whether the same association exists in middle-aged persons. The Atherosclerosis Risk in Communities Study is a cohort study initiated in 1987 to investigate the development of atherosclerosis in middle-aged persons. Three cognitive function measures were included in the second cohort examination conducted from 1990 to 1992 when the participants were aged 48-67 years: the Delayed Word Recall Test (DWRT), the Digit Symbol Substitution Test (DSST) (a subtest from the Wechsler Adult Intelligence Scale-Revised), and the Word Fluency Test from the Multilingual Aphasia Examination. Cox proportional hazards modeling was used to determine whether all-cause mortality ascertained through 1997 was associated with each measure after adjustment for sociodemographic, biologic, psychologic, and behavioral risk factors. Without adjustment, there was a significantly lower mortality hazard associated with higher scores on all three measures. After covariate adjustment, the hazard ratios for the DWRT and the DSST remained significant (hazard ratio1-point DWRT score increment = 0.90, 95% confidence interval: 0.84, 0.97; hazard ratio 7-point DSST score increment = 0.86, 95% confidence interval: 0.80, 0.93). Cognitive function measured in middle age appears to have prognostic importance for life expectancy similar to that reported in elderly adults.
Pavlik
Valory N
VN
Department of Family and Community Medicine, Baylor College of Medicine, Houston, TX 77005, USA. vpavlik@bcm.tmc.edu
de Moraes
Suzana Alves
SA
Szklo
Moyses
M
Knopman
David S
DS
Mosley
Thomas H
TH
Hyman
David J
DJ
D000368:Aged; D000375:Aging / Q000502:physiology; D000704:Analysis of Variance; D002423:Cause of Death; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors