Relation between Cognitive Function and Mortality in Middle-aged Adults: The Atherosclerosis Risk in Communities Study

Abstract

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.

Does cognition predict mortality in midlife? Results from the Whitehall II cohort study

“…The association between cognition and mortality appears robust and most measures of cognition have been shown to be associated with mortality (Anstey et al, 2001;Hassing et al, 2002;Korten et al, 1999;Pavlik et al, 2003;Portin et al, 2001;Shipley et al, 2006;Small et al, 2003;Smits et al, 1999). However, comparisons between different cognitive measures in the elderly reveal, in one study, visuospatial reasoning, verbal fluency and short-term but not working memory to be associated with mortality (Small et al, 2003).…”

“…The explanatory variables previously examined to explore the association between cognition and mortality have included socioeconomic variables (Anstey et al, 2001;Hart et al, 2005;Hassing et al, 2002;Korten et al, 1999;Kuh et al, 2004;Pavlik et al, 2003;Portin et al, 2001;Shipley et al, 2006;Small et al, 2003;Small and Backman, 1997;Smits et al, 1999;Whalley and Deary, 2001), health behaviours (Holsinger et al, 2007;Korten et al, 1999;Kuh et al, 2004;Pavlik et al, 2003;Shipley et al, 2006) and measures of health (Anstey et al, 2001;Hassing et al, 2002;Holsinger et al, 2007;Korten et al, 1999;Kuh et al, 2004;Pavlik et al, 2003;Portin et al, 2001;Shipley et al, 2006;Small et al, 2003;Smits et al, 1999). The different results on the role played by explanatory variables are probably due to differences in measures of cognition and the covariates examined.…”

Sex Differences in Health and Survival

“…Empirical research has consistently demonstrated that poor cognitive function is associated with increased mortality risk in older populations (Gale et al 1996;Pavlik et al 2003;Perna et al 2015). In contrast, studies on predictive abilities of cognitive decline beyond current levels of cognitive function have reached competing conclusions (Maier et al 2003;Schupf et al 2005;Ghisletta 2008;Lavery et al 2009).…”

Premorbid (early life) IQ and Later Mortality Risk: Systematic Review

“…During the last decade, investigators began to examine the predictive significance of IQ for health outcomes (1). Several studies of middle-aged (2,3) and, particularly, older-aged (4,5) adults found that those with higher scores on tests of mental ability had lower rates of later all-cause mortality. These associations may occur across the full range of test scores (6,7), rather than just in persons with severe mental impairment, although this is not a universal observation (4).…”