Risk factors of transition from mild cognitive impairment to Alzheimer's disease and death: A cohort study

Background: Knowledge of risk factors is essential for developing strategies that prevent or minimise transitions from mild cognitive impairment (MCI) to Alzheimer's disease (AD) and death. The aim of this study was to assess risk factors for progression to AD and death among Chinese individuals with cognitive impairment. Methods: We conducted a multisite, population-based cohort study on 437 community-dwelling elderly MCI residents in Taiyuan, China from 2010 to 2014. MCI, AD, death from AD and death from a cause other than AD were specified as disease states during the natural history of dementia. Transition-specific Cox model was fitted and hazard ratio (HR) with 95% confidence intervals (CIs) was estimated. Results: Analyses showed that risk factors played different roles in affecting transitions to AD and death. Risk factors for transition from MCI to AD were being female (HR: 1.82; 95%CI: 1.20-2.77), older age (HR: 3.09; 95%CI: 1.81-5.25), reading occasionally (HR: 1.79; 95%CI: 1.11-2.89), current smoking (HR: 1.74; 95%CI: 1.15-2.65), light moderate alcohol drinker (HR: 2.24; 95%CI: 1.42-3.53), cerebrovascular disease (HR: 2.70; 95%CI: 1.68-4.34), hyperlipidemia (HR: 1.87; 95%CI: 1.16-3.02) and diabetes (HR: 1.81; 95%CI: 1.18-2.77). Only cerebrovascular disease (HR: 3.04; 95%CI: 1.22-7.58) was a significant risk factor for transition from MCI to death from a cause other than AD. Older age (HR: 10.68; 95%CI: 1.16-97.93) and low level education (HR: 0.14; 95%CI: 0.05-0.44) were significant predictors for transition from AD to death from a cause other than AD. Conclusions: Participants with advanced age, low-level education, history of harmful alcohol consumption or smoking, cerebrovascular disease, hyperlipidemia, diabetes or who were female were at increased risk of transitioning to AD or death. Strategies to control modifiable risk factors in specific disease stage should be implemented to decrease the conversion to AD or death among Chinese patients with MCI. (C) 2017 Elsevier Inc. All rights reserved.