Worldwide prevalence of mild cognitive impairment among community dwellers aged 50 years and older: a meta-analysis and systematic review of epidemiology studies.

Mild cognitive impairment (MCI) is the preclinical and transitional stage between healthy ageing and dementia that may be a potential 'target' for interventions designed to delay progression to dementia. In this systematic review and meta-analysis, we assessed the prevalence of MCI worldwide in community-dwelling adults aged 50 years and older.PubMed, Web of Science, Embase and PsycINFO database searches were conducted from their respective inception dates to 1 September 2021. Data on the overall prevalence of MCI were synthesised using random effects models.A total of 66 articles covering 242,804 participants fulfilled study criteria for inclusion. The overall prevalence of MCI was 15.56% (95%CI: 13.24-18.03%). Prevalence rates of amnestic MCI and non-amnestic MCI were 10.03% (95%CI: 7.98-12.27%) and 8.72% (95%CI: 6.78-10.89%), respectively. The prevalence of MCI increased with age and decreased with education level. Subgroup and meta-regression analyses revealed that region of study site and male gender proportion per sample were significant correlates of MCI prevalence.The global prevalence of MCI among community dwellers is over 15% and is affected by age, gender, education level and region of study sites. Assessment and interventions targeting MCI within at-risk population subgroups should be considered toward the prevention of dementia.