title: Cognitive impairment and mortality in older healthy Mexican subjects: a population-based 10-year follow-up study.
abstract: OBJECTIVE
  To estimate the incidence of cognitive impairment (CI) among cognitively healthy, Mexican subjects, and to evaluate the impact of demographic and vascular factors on the conversion to CI and mortality.
  
  
  METHODS
  734 eligible subjects (aged 55 to >90 years) from a population-based sample were examined. The cognitive function of participants was assessed using the Mini-Mental State Examination (MMSE) every 2 years. The subjects were followed for an average of 3.2 years. The CI was defined using two sets of criteria: (i) moderate CI, as a drop to 25-21 on the MMSE at 2-year follow-up or a decrease of at least four points and (ii) severe CI, defined as a drop of 21 or less in MMES at follow-up. The incidence density and period prevalence were determined as epidemiological measures as well as the cumulative incidence as a risk measure. Kaplan-Meier survival curves were used to analyse the main points of interest: CI, dementia and mortality.
  
  
  RESULTS
  The period prevalence of moderate CI was 20%, and 10% for severe CI. During 1959 person-years of follow-up, severe CI developed in 33 of the 361 participants. While during 2096 person-years of follow-up; 80 of 361 participants developed moderate CI. The rate of progression to severe CI in moderate CI subjects gradually increases with follow-up. Both, moderate and severe CI were associated with low educational level, higher age and higher mortality.
  
  
  CONCLUSIONS
  Elderly people with moderate CI have an increased risk of severe CI. Moderate and severe CI are both predictive of higher mortality in Mexican subjects.
authors.affiliation: Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez; México City, Mexico. arauzg@prodigy.net.mx
authors.forename: Antonio
authors.initials: A
authors.lastname: Arauz
authors.forename: Elisa
authors.initials: E
authors.lastname: Alonso
authors.forename: Joel
authors.initials: J
authors.lastname: Rodríguez-Saldaña
authors.forename: Marco
authors.initials: M
authors.lastname: Reynoso-Marenco
authors.forename: Ivor Toledo
authors.initials: IT
authors.lastname: Benitez
authors.forename: Arely Monroy
authors.initials: AM
authors.lastname: Mayorga
authors.forename: Yaneth
authors.initials: Y
authors.lastname: Rodríguez-Agudelo
authors.forename: Antonio Villa
authors.initials: AV
authors.lastname: Romero
authors.forename: Carlos
authors.initials: C
authors.lastname: Cantú
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000453:epidemiology*; D015897:Comorbidity; D003704:Dementia / Q000453:epidemiology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D015993:Life Tables; D008297:Male; D008569:Memory Disorders / Q000453:epidemiology; D008800:Mexico; D008875:Middle Aged; D009026:Mortality / Q000639:trends; D015995:Prevalence; D011379:Prognosis; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012907:Smoking / Q000453:epidemiology; D016019:Survival Analysis