Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
ISSN-L : 0917-5040
Original Article
Information Processing Speed and 8-Year Mortality Among Community-Dwelling Elderly Japanese
Hajime IwasaIchiro KaiYuko YoshidaTakao SuzukiHunkyung KimHideyo Yoshida
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Supplementary material

2014 Volume 24 Issue 1 Pages 52-59


Background: Cognitive function is an important contributor to health among elderly adults. One reliable measure of cognitive functioning is information processing speed, which can predict incident dementia and is longitudinally related to the incidence of functional dependence. Few studies have examined the association between information processing speed and mortality. This 8-year prospective cohort study design with mortality surveillance examined the longitudinal relationship between information processing speed and all-cause mortality among community-dwelling elderly Japanese.
Methods: A total of 440 men and 371 women aged 70 years or older participated in this study. The Digit Symbol Substitution Test (DSST) was used to assess information processing speed. DSST score was used as an independent variable, and age, sex, education level, depressive symptoms, chronic disease, sensory deficit, instrumental activities of daily living, walking speed, and cognitive impairment were used as covariates.
Results: During the follow-up period, 182 participants (133 men and 49 women) died. A multivariate Cox proportional hazards model showed that lower DSST score was associated with increased risk of mortality (hazard ratio [HR] = 1.62, 95% CI = 0.97–2.72; HR = 1.73, 95% CI = 1.05–2.87; and HR = 2.55, 95% CI = 1.51–4.29, for the third, second, and first quartiles of DSST score, respectively).
Conclusions: Slower information processing speed was associated with shorter survival among elderly Japanese.

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© 2013 Hajime Iwasa et al. This is an open access article distributed under the terms of Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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