title: Prevalence, distribution, and impact of mild cognitive impairment in Latin America, China, and India: a 10/66 population-based study.
abstract: BACKGROUND
  Rapid demographic ageing is a growing public health issue in many low- and middle-income countries (LAMICs). Mild cognitive impairment (MCI) is a construct frequently used to define groups of people who may be at risk of developing dementia, crucial for targeting preventative interventions. However, little is known about the prevalence or impact of MCI in LAMIC settings.
  
  
  RESULTS
  Data were analysed from cross-sectional surveys established by the 10/66 Dementia Research Group and carried out in Cuba, Dominican Republic, Peru, Mexico, Venezuela, Puerto Rico, China, and India on 15,376 individuals aged 65+ without dementia. Standardised assessments of mental and physical health, and cognitive function were carried out including informant interviews. An algorithm was developed to define Mayo Clinic amnestic MCI (aMCI). Disability (12-item World Health Organization disability assessment schedule [WHODAS]) and informant-reported neuropsychiatric symptoms (neuropsychiatric inventory [NPI-Q]) were measured. After adjustment, aMCI was associated with disability, anxiety, apathy, and irritability (but not depression); between-country heterogeneity in these associations was only significant for disability. The crude prevalence of aMCI ranged from 0.8% in China to 4.3% in India. Country differences changed little (range 0.6%-4.6%) after standardization for age, gender, and education level. In pooled estimates, aMCI was modestly associated with male gender and fewer assets but was not associated with age or education. There was no significant between-country variation in these demographic associations.
  
  
  CONCLUSIONS
  An algorithm-derived diagnosis of aMCI showed few sociodemographic associations but was consistently associated with higher disability and neuropsychiatric symptoms in addition to showing substantial variation in prevalence across LAMIC populations. Longitudinal data are needed to confirm findings-in particular, to investigate the predictive validity of aMCI in these settings and risk/protective factors for progression to dementia; however, the large number affected has important implications in these rapidly ageing settings.
authors.affiliation: National Institute of Neurology and Neurosurgery, Autonomous National University of Mexico, Mexico City, Mexico.
authors.forename: Ana Luisa
authors.initials: AL
authors.lastname: Sosa
authors.forename: Emiliano
authors.initials: E
authors.lastname: Albanese
authors.forename: Blossom C M
authors.initials: BC
authors.lastname: Stephan
authors.forename: Michael
authors.initials: M
authors.lastname: Dewey
authors.forename: Daisy
authors.initials: D
authors.lastname: Acosta
authors.forename: Cleusa P
authors.initials: CP
authors.lastname: Ferri
authors.forename: Mariella
authors.initials: M
authors.lastname: Guerra
authors.forename: Yueqin
authors.initials: Y
authors.lastname: Huang
authors.forename: K S
authors.initials: KS
authors.lastname: Jacob
authors.forename: Ivonne Z
authors.initials: IZ
authors.lastname: Jiménez-Velázquez
authors.forename: Juan J Llibre
authors.initials: JJ
authors.lastname: Rodriguez
authors.forename: Aquiles
authors.initials: A
authors.lastname: Salas
authors.forename: Joseph
authors.initials: J
authors.lastname: Williams
authors.forename: Isaac
authors.initials: I
authors.lastname: Acosta
authors.forename: Maribella
authors.initials: M
authors.lastname: González-Viruet
authors.forename: Milagros A Guerra
authors.initials: MA
authors.lastname: Hernandez
authors.forename: Li
authors.initials: L
authors.lastname: Shuran
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Prince
authors.forename: Robert
authors.initials: R
authors.lastname: Stewart
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000465:Algorithms; D001007:Anxiety / Q000150:complications; D002681:China / Q000453:epidemiology; D003072:Cognition Disorders / Q000150:complications / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D003704:Dementia / Q000209:etiology*; D003906:Developing Countries; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D007843:Latin America / Q000453:epidemiology; D008297:Male; D001523:Mental Disorders / Q000150:complications*; D009483:Neuropsychological Tests; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D012923:Social Class