Cognitive impairment and mortality among the oldest-old Chinese

ObjectiveThis study examined the relationship between cognitive impairment status and all-cause mortality among the oldest-old Chinese. MethodsA total of 7474 survey participants 80years of age and above came from the Chinese Longitudinal Healthy Longevity Survey 1998-2012 waves. Baseline cognitive impairment status was assessed using the Chinese version of the mini-mental state examination (MMSE), with total score ranging from 0 to 30. Cox proportional hazards regressions were performed to examine the relationship between baseline cognitive impairment status in 1998 and subsequent all-cause mortality during 1998-2012, adjusting for various individual characteristics at baseline. ResultsCompared with those with no or mild cognitive impairment (18MMSE score30) at baseline, participants with moderate-to-severe cognitive impairment (0MMSE score17) were 28% (95% confidence interval=20%, 37%) more likely to die during the follow-up period from 1998 to 2012. A dose-response relationship between baseline severity level of cognitive impairment and mortality was evident. Compared with those without cognitive impairment (25MMSE score30) at baseline, those having mild cognitive impairment (18MMSE score24), moderate cognitive impairment (10MMSE score17), and severe cognitive impairment (0MMSE score9), were 20% (13%, 28%), 38% (27%, 51%), and 47% (33%, 62%) more likely to die during the follow-up period. No statistically significant gender differences in the relationship between cognitive impairment status and mortality were found. ConclusionBaseline cognitive impairment was inversely associated with longevity among the oldest-old Chinese. Copyright (c) 2016 John Wiley & Sons, Ltd.