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AlzRisk Cohort Detail

Cohort: Adult Changes in Thought-Group Health Cooperative
Risk Factors:

Introduction to the Cohort
Between 1994 and 1996, the Adult Changes in Thought (ACT) study enrolled 2,581 cognitively intact adults, aged 65 and older and members of the Group Health Cooperative (GHC) health care system in the Seattle area, Washington, USA. Investigators enrolled an additional 811 individuals from 2000-2002, for a total of 3,392 participants. Since enrollment, participants have undergone evaluations every two years. The purpose of the ACT study is to prospectively examine the incidence of AD and dementia, as well as risk factors for those conditions. At enrollment, 23% of the original cohort members (those enrolled from 1994-1996) were aged 65-69, 30% were 70-74, 24% were 75-79, 15% were 80-84, and 7% were 85 or older. Fifty-nine percent were female. The population from which the cohort members were sampled was middle class.

Ethnicity Breakdown
Nearly all original cohort members (91%) were white, 4% were African-American, and the remaining were of other or unspecified origin.

Diagnosis & Evaluation Methods
For a detailed description, see Kukull WA et al. 2002.

Gray SL, Anderson ML, Crane PK, Breitner JC, McCormick W, Bowen JD, Teri L, Larson E. Antioxidant vitamin supplement use and risk of dementia or Alzheimer's disease in older adults. J Am Geriatr Soc. 2008 Feb;56(2):291-5.

Group Health Center for Health Studies. Aging and geriatrics, available at Accessed on Jun 12, 2009.

Kukull WA, Higdon R, Bowen JD et al. Dementia and Alzheimer disease incidence: A prospective cohort study. Arch Neurol 2002;59:1737–1746.