title: Staging cognitive impairment and incidence of dementia.
abstract: OBJECTIVE
  In a background of interest in staging models in psychiatry, we tested the validity of a simple staging model of cognitive impairment to predict incident dementia.
  
  
  METHODS
  A large community sample of adults aged ≥55 years (N = 4803) was assessed in the baseline of a longitudinal, four-wave epidemiological enquiry. A two-phase assessment was implemented in each wave, and the instruments used included the Mini-Mental Status Examination (MMSE); the History and Aetiology Schedule and the Geriatric Mental State-AGECAT. For the standardised degree of cognitive impairment Perneczky et al's MMSE criteria were applied. A panel of psychiatrists diagnosed cases of dementia according to DSM-IV criteria, and cases and sub-cases of dementia were excluded for the follow-up waves. Competing risk regression models, adjusted by potential confounders, were used to test the hypothesised association between MMSE levels and dementia risk.
  
  
  RESULTS
  Out of the 4057 participants followed up, 607 (14.9%) were classified as 'normal' (no cognitive impairment), 2672 (65.8%) as 'questionable' cognitive impairment, 732 (18.0%) had 'mild' cognitive impairment, 38 (0.9%) had 'moderate' cognitive impairment and eight (0.2%) had 'severe' impairment. Cognitive impairment was associated with risk of dementia, the risk increasing in parallel with the level of impairment (hazard ratio: 2.72, 4.78 and 8.38 in the 'questionable', 'mild' and 'moderate' level of cognitive impairment, respectively).
  
  
  CONCLUSIONS
  The documented gradient of increased risk of dementia associated with the severity level of cognitive impairment supports the validity of the simple staging model based on the MMSE assessment.
authors.affiliation: Department of Preventive Medicine and Public Health,Universidad de Zaragoza,Zaragoza,Spain.
authors.forename: J
authors.initials: J
authors.lastname: Santabárbara
authors.affiliation: Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM).Ministry of Science and Innovation,Madrid,Spain.
authors.forename: R
authors.initials: R
authors.lastname: Lopez-Anton
authors.affiliation: Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM).Ministry of Science and Innovation,Madrid,Spain.
authors.forename: P
authors.initials: P
authors.lastname: Gracia-García
authors.affiliation: Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM).Ministry of Science and Innovation,Madrid,Spain.
authors.forename: C
authors.initials: C
authors.lastname: De-la-Cámara
authors.affiliation: Department of Medicine and Psychiatry,Universidad de Zaragoza,Zaragoza,Spain.
authors.forename: D
authors.initials: D
authors.lastname: Vaquero-Puyuelo
authors.affiliation: Department of Preventive Medicine and Public Health,Universidad de Zaragoza,Zaragoza,Spain.
authors.forename: E
authors.initials: E
authors.lastname: Lobo
authors.affiliation: Department of Preventive Medicine and Public Health,Universidad de Zaragoza,Zaragoza,Spain.
authors.forename: G
authors.initials: G
authors.lastname: Marcos
authors.affiliation: Faculty of Health Sciences,Centre for Disability Research and Policy,University of Sydney,Australia.
authors.forename: L
authors.initials: L
authors.lastname: Salvador-Carulla
authors.affiliation: Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM).Ministry of Science and Innovation,Madrid,Spain.
authors.forename: T
authors.initials: T
authors.lastname: Palomo
authors.affiliation: Association for the Improvement of Mental Health Programmes (AMH),Geneva,Switzerland.
authors.forename: N
authors.initials: N
authors.lastname: Sartorius
authors.affiliation: Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM).Ministry of Science and Innovation,Madrid,Spain.
authors.forename: A
authors.initials: A
authors.lastname: Lobo
mesh_terms: D003072:Cognition Disorders; D060825:Cognitive Dysfunction / Q000150:complications*; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012306:Risk
keywords: Cognitive impairment; Mini-Mental Status Examination; dementia; staging