Prevalence of mild cognitive impairment in community-dwelling Chinese populations aged over 55 years: a meta-analysis and systematic review

Abstract

Background Mild cognitive impairment (MCI) is an intermediate phase between normal cognitive ageing and overt dementia, with amnesic MCI (aMCI) being the dominant subtype. This study aims to synthesise the prevalence results of MCI and aMCI in community-dwelling populations in China through a meta-analysis and systematic review. Methods The study followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) protocol. English and Chinese studies published before 1 March 2020 were searched from ten electronic bibliographic databases. Two reviewers screened for relevance of the studies against the pre-defined inclusion and exclusion criteria and assessed the quality of the included studies using the Risk of Bias Tool independently. A random-effect model was adopted to estimate the prevalence of MCI and aMCI, followed by sub-group analyses and meta-regression. Sensitivity and publication bias tests were performed to verify the robustness of the meta-analyses. Results A total of 41 studies with 112,632 participants were included in the meta-analyses. The Chinese community-dwelling populations over 55 years old had a pooled prevalence of 12.2% [95% confidence interval (CI): 10.6, 14.2%] for MCI and 10.9% [95% CI, 7.7, 15.4%] for aMCI, respectively. The prevalence of MCI increased with age. The American Psychiatric Association’s Diagnostic tool (DSM-IV) generated the highest MCI prevalence (13.5%), followed by the Petersen criteria (12.9%), and the National Institute on Aging Alzheimer’s Association (NIA-AA) criteria (10.3%). Women, rural residents, and those who lived alone and had low levels of education had higher MCI prevalence than others. Conclusion Higher MCI prevalence was identified in community-dwelling older adult populations in China compared with some other countries, possibly due to more broadened criteria being adopted for confirming the diagnosis. The study shows that aMCI accounts for 66.5% of MCI, which is consistent with findings of studies undertaken elsewhere. Systematic review registration number PROSPERO CRD42019134686.

Demographic and Clinical Profile of Patients with Mild Cognitive Impairment Seen at St. Luke’s Medical Center-Global City Memory Service

“…More female patients were diagnosed with MCI at 58.3% consistent with findings in other population [2]. Other studies have also shown how the female sex tend to exhibit lower ADAS-Cog scores when followed up for over 8-10 years, highlighting the influence of female sex as a risk for progression [12,13].…”

“…The patients seen in the Memory Center actively seek consult due to subjective cognitive concerns from the patients themselves, their families, or their referring doctors; thus, the diagnosis and prevalence of MCI are higher than a community setting. Literature reported that MCI is more frequent among patients from rural communities [2], but the Memory Center is a specialty referral unit and caters to patients from both rural and urban areas. This should be highlighted and considered when comparing our study results with those researches among community-dwelling individuals.…”

“…Mild cognitive impairment (MCI) is an intermediate state between normal aging and dementia in which there is preservation of function in the presence of cognitive deficit/s [1]. Prevalence of MCI in people 60 years and older range from 15 to 20% [1], although a 12.2% prevalence among community dwelling individuals in China was a recent finding [2]. A subset of these patients are known to progress to different types of dementia, and as such, understanding the factors associated with this con-dition is of significance.…”

“…In a longitudinal study of MCI in Chinese older adults with multimorbidity, age and nonmarried status were identified as risk factors for this condition [11]. A recent study identified women, rural residents, those living alone, and with lower level of education to have higher prevalence of MCI [2]. Women [12, 13] and those with less years of formal education [9] were also found to be predictors of cognitive decline.…”

Electrophysiological Studies of Cognitive Reappraisal Success and Failure in aMCI

“…Amnestic mild cognitive impairment (aMCI) is a dominant subtype of MCI in which memory loss is the predominant symptom, accounting for 66.5% of all MCI cases [1]. People with aMCI are more likely than other subtypes to develop dementia, which is considered a precursor to Alzheimer's disease (AD) [2][3][4].…”