Objective: Because the number of elderly is increasing worldwide, cognitive dysfunction becomes important health care issue. This study investigated the association between cognitive dysfunction and mortality in the elderly.
Method: Data were analyzed from a longitudinal mortality follow-up study of 2712 Korean elderly aged 60 and over, examined in 2002 with complete data followed an average 6.03 years. Measurements included socio-demographic and clinical factors and Mini-Mental State Examination (MMSE). MMSE was categorized into groups with no, mild, or moderate cognitive dysfunction, and the subscores of MMSE domains were categorized into no dysfunction or dysfunction. The Cox proportional hazards models were conducted to examine the association between MMSE score and mortality, after adjusting for age, gender, education and other socio-demographic factors.
Results: Death during follow-up occurred in 318 subjects. The mortality risk was significantly associated with the elderly with mild cognitive dysfunction [hazard ratio (HR) = 1.93] and with moderate cognitive dysfunction (HR = 2.66). ‘Orientation-to-time’ (HR = 1.39) and ‘Attention’ (HR = 1.48) domains of MMSE were independently associated with mortality.
Conclusion: This study showed that cognitive dysfunction independently predicted mortality in the elderly. Cognitive dysfunction should be considered part of identifying the elderly at high risk for mortality.