Prevalence of dementia in Chamorros on Guam: relationship to age, gender, education, and APOE

Neurology. 2007 May 22;68(21):1772-81. doi: 10.1212/01.wnl.0000262028.16738.64.


Objectives: To estimate the prevalence of dementia and its clinical subtypes among Chamorros on Guam aged 65 years or older and to examine associations with age, gender, education, and APOE genotype.

Background: Chamorros, the indigenous people of Guam, had a high incidence of ALS and parkinsonism-dementia complex (PDC), in the 1950s. Over the next 50 years, ALS incidence declined markedly, but PDC only slightly. The prevalence of late life dementia in Chamorros and its relationship to ALS/PDC are unknown.

Methods: Island-wide population-based survey of Chamorros aged 65 years or older as of January 1, 2003. Two-stage assessment: cognitive and motor screening, followed by neurologic and psychometric evaluation. Data were reviewed at consensus conference to make clinical diagnoses.

Results: Of 2,789 Chamorros aged 65 years or older, 73% were enrolled; 27% declined participation, died before contact or screening, or moved off Guam. The point prevalence of all-cause dementia on February 1, 2004, was 12.2%. Prevalence data for subtypes were as follows: Guam dementia (clinically equivalent to AD), 8.8%; PDC, 1.5%; pure vascular dementia, 1.3%; other, 0.6%. The prevalence of dementia rose exponentially with age. Low education was significantly associated with dementia, but gender was not. There was a trend toward higher PDC prevalence among men. The APOE epsilon4 allele was not associated with dementia.

Conclusions: The prevalence of dementia among elderly Chamorros is relatively high. Guam dementia is the most common diagnosis and exceeds parkinsonism-dementia complex. Age and low education are strongly associated with dementia, but gender and APOE epsilon4 are not. Incidence studies will allow risk factors for dementia to be clarified.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Age Distribution
  • Aged
  • Amyotrophic Lateral Sclerosis / ethnology
  • Amyotrophic Lateral Sclerosis / genetics
  • Apolipoproteins E / genetics*
  • Cross-Sectional Studies
  • DNA Mutational Analysis
  • Dementia / ethnology*
  • Dementia / genetics*
  • Educational Status
  • Female
  • Genetic Predisposition to Disease / genetics*
  • Genetic Testing
  • Genotype
  • Guam / epidemiology
  • Humans
  • Male
  • Native Hawaiian or Other Pacific Islander / genetics
  • Neurologic Examination
  • Neuropsychological Tests
  • Parkinsonian Disorders / ethnology
  • Parkinsonian Disorders / genetics
  • Prevalence
  • Sex Distribution


  • Apolipoproteins E