Mortality in Nondemented Subjects with Cognitive Impairment: The Influence of Health-related Factors

Abstract

Nondemented older subjects with cognitive impairment are at higher risk of death than are mentally intact persons. It is unknown whether the effect of cognitive impairment on mortality is independent or mediated by poorer health or other factors. To address this issue, the authors used a prospective population-based cohort study with 8 years of follow-up started in 1987 in the urban district of Kungsholmen, Stockholm, Sweden. Subjects were all 75- to 95-year-old subjects nondemented at baseline (n = 1,435). Data on cognition, health (mental and subjective health, physical diseases and comorbidity, nutritional status, and disability), and apolipoprotein E genotype were collected at baseline as was time of death at follow-up. Cognitive impairment was defined on the basis of age- and education-specific cutoffs on the Mini-Mental State Examination. When compared with cognitively unimpaired subjects (n = 1,210), those cognitively impaired (n = 225) had poorer health conditions, were more frequently apolipoprotein E epsilon4 carriers, and had greater mortality risk (hazard ratio = 1.7; 95% confidence interval: 1.5, 2.1). Neither health nor apolipoprotein E genotype accounted for the association of cognitive impairment with mortality (adjusted hazard ratio = 1.6; 95% confidence interval: 1.3, 1.9). The functional and behavioral consequences associated with the progression of cognitive impairment may mediate the increased mortality risk.

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

“…Our results show that health behaviours explained a considerable part of the association between cognition and mortality among middle-aged individuals. Many previous studies have either not examined the role of health behaviours (Anstey et al, 2001;Frisoni et al, 1999;Hart et al, 2005;Hassing et al, 2002;Kelman et al, 1994;Liu et al, 1990;Nguyen et al, 2003;Portin et al, 2001;Rabbitt et al, 2002;Small et al, 2003;Smits et al, 1999;Whalley and Deary, 2001) or not separated their effects from those of socioeconomic variables . Measures of health, as indirect measures of system integrity, explain less of the association with memory compared to the other measures of cognition.…”

The UCSD Statin Study: a randomized controlled trial assessing the impact of statins on selected noncardiac outcomes

“…Changes in cognition, depression, and fitness have marked mortality implications in this group [22,[32][33][34][35][36][37][38][39][40][41][42][43][44][45].…”

Desempeño cognoscitivo y mortalidad en personas mayores de 50 años en México

“…Los resultados del presente estudio coinciden en resaltar la asociación entre los valores bajos en pruebas cognoscitivas y la mortalidad publicados por otros autores en distintas poblaciones (10)(11)(12)(13)(14)(15)(16)(17)19). Una revisión sistemática realizada por Batty y colaboradores mostró una relación inversa entre el coeficiente intelectual en adultos jóvenes y la mortalidad (17), que aunque no es comparable con la población mexicana aquí estudiada, confirma dicha asociación independientemente de la edad de los participantes.…”

“…No obstante, la definición empleada en la población es de carácter estadístico y se ajusta según edad y años de escolaridad (9), además de que en el caso de la demencia se requiere una falla en el funcionamiento de las actividades diarias. Hay datos que demuestran que los bajos desempeños cognoscitivos se asocian con una mortalidad y morbilidad importantes, que pueden llegar a ser hasta dos veces más elevadas en las personas con dichos trastornos en comparación con quienes no los padecen (10)(11)(12)(13)(14)(15)(16)(17).…”