Prevalence, Cognitive Characteristics and Influence Factors of Amnestic Mild Cognitive Impairment among Community-dwelling Older Adults in Chengdu, China

Abstract

Background: Dementia is a global public health priority. Mild cognitive impairment (MCI) is a transitional stage between normal aging and dementia. And amnestic MCI (aMCI) is proved to have a higher probability to develop into AD comparing to other type of MCI. Yet a few studies have focused on prevalence of aMCI in China. This study aims to explore the prevalence of amnestic mild cognitive impairment (aMCI), cognitive characteristics of aMCI, and associated risk factors for aMCI.Methods: A cross-sectional study was conducted in the communities of Chengdu, China. Participants were 368 older adults aged 60 years and over. Participants completed various neuropsychological assessments, including the Mini-Mental State Examination (MMSE), the Clinical Dementia Rating (CDR), Auditory Verbal Learning Test (AVLT), Wechsler’s Logical Memory Task (LMT), Boston Naming Test (BNT) and Trail Making Test Part A (TMT-A). Social information was collected by standard questionnaire. Multiple logistic regression analysis was utilized to screen for the risk and protective factors of aMCI.Results: Data included 309 subjects with normal cognitive function and 59 with aMCI. The prevalence of aMCI was 16.0%.The average age of participants was 69.06±7.30 years, with 56.0% being females. After controlling for age, gender and education, the Spearman partial correlation coefficient between diverse cognitive assessments and aMCI ranged from -0.52 for the long-term delayed recall scores in AVLT to 0.19 for the time-usage scores in TMT-A, and results revealed that all domains except naming scores (after semantic cue of BNT) and error quantity (in TMT-A) showed statistically significant associations with aMCI. And the results of multiple logistic regression analysis indicated that older age (OR=1.044, 95%CI: 1.002~1.087, p=0.042), lower educational level, and diabetes (OR=2.450, 95%CI: 1.246~4.818, p=0.009) were risk factors of aMCI.Conclusions: Participants with aMCI showed lower cognitive function in memory, language and executive domains, especially in long-term delayed recall. The participants who were older, had less education, or with diabetes had higher risk of suffering from aMCI. These results may help clinical practitioners design and conduct targeted cognitive training and chronic disease management for the elderly, aiming to prevent and delay development of Alzheimer’s dementia.