Mild cognitive impairment in the general population: occurrence and progression to Alzheimer disease

Am J Geriatr Psychiatry. 2008 Jul;16(7):603-11. doi: 10.1097/JGP.0b013e3181753a64.


Objectives: Our aims were to 1) detect the occurrence of three mild cognitive impairment (MCI) subtypes in the general population; 2) identify cases of cognitive impairment which are not detected by current operational criteria for MCI and; 3) determine the predictive value of the subtypes for identifying future Alzheimer disease (AD).

Design: Three-year prospective study.

Setting: Population-based Swedish study, the Kungsholmen Project.

Participants: Three hundred seventy-nine nondemented older adults aged 75-95.

Measurements: Standard plus modified MCI criteria were applied at baseline. In the modified definitions, the requirement for normal general cognition was removed. A category for persons without MCI who had only global cognitive deficits was added. Three-year progression to AD was assessed (DSM-III-R criteria).

Results: Occurrence per 100 nondemented persons of MCI-amnestic, MCI-multidomains, and MCI-single-nonmemory was 2.1%, 1.8%, and 7.2%, respectively. When applying modified definitions for MCI-amnestic and MCI-multidomains, the occurrence almost doubled. Seven percent of the sample had impairment on a global cognitive task but performed at normal levels on all other domain-specific tasks. MCI-multidomains showed the highest progression to AD (hazard ratio [HR]: 23.6, 9.3-60.1). MCI-amnestic reached similar predictivity only when using the modified definition (HR: 17.9, 6.8-46.9). Even participants without MCI who had only global deficits had a ninefold risk of AD (HR: 9.1, 2.8-29.4).

Conclusions: Two-thirds of MCI-multidomains, but only half of MCI-amnestic progress to AD. The standard MCI criteria failed to identify those people with global cognitive deficits who have, however, a high risk of progressing to AD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Cognition Disorders / classification
  • Cognition Disorders / diagnosis*
  • Cognition Disorders / epidemiology*
  • Dementia / diagnosis*
  • Dementia / epidemiology*
  • Dementia / psychology
  • Diagnostic and Statistical Manual of Mental Disorders
  • Disease Progression
  • Female
  • Humans
  • Male
  • Memory Disorders / classification
  • Memory Disorders / diagnosis
  • Memory Disorders / epidemiology
  • Predictive Value of Tests
  • Prevalence
  • Proportional Hazards Models
  • Prospective Studies
  • Risk
  • Sweden / epidemiology