Adult Changes in Thought Study

The Adult Changes in Thought (ACT) is a prospective cohort study that focuses on dementia and Alzheimer's disease.  It aims to create a "living laboratory" to study aging and dementia in older adults.The ACT study collects a variety of detailed information on demographics, risk factors, lifestyle, genetics, comorbidities, and outcomes and shares these data with interested investigators throughout the world.

Overview

Acronym
ACT
Website
ACT
Investigators
Dr. Eric B. Larson
Group Health Research Institute
MD. Paul Crane
University of Washington
Contacts
Erin Bowles
Group Health Research Institute
Darlene White
Group Health Research Institute
KatieRose Richmire
Group Health Research Institute

General Design

Study design
Cohort
Start - End Year
1994 -
General Information on Follow Up (profile, frequency)

The participants are followed up with interviews every two years until diagnosis of dementia and/or Alzheimer's disease.

Recruitment Target
  • Individuals
Number of Participants
4,960 (No Limit)
Number of Participants with Biological Samples
4,960 (No Limit)
Supplementary information about number of participants

The ACT study is made up of three cohorts:

From 1994-1996 we enrolled a cohort of 2,581 people aged 65 years and older without dementia.

From 2000-2002, we enrolled an expansion cohort of 811 people using the same inclusion criteria.

From 2004-present, we began continuous enrollment using the same inclusion criteria to replace attrition from dementia, dropout, and death. We have a consistent cohort of ~2000 at risk for dementia. The total current enrollment of all three groups is 4,960.

Access

Availability of data and biosamples

Possible Access to Data
Possible Access to Biosamples
Other

Marker Papers

Kukull WA, Higdon R, Bowen JD, et al. Dementia and Alzheimer Disease Incidence: A Prospective Cohort Study. Arch Neurol. 2002;59(11):1737-1746. doi:10.1001/archneur.59.11.1737.

PUBMED 12433261

Timeline

Population

ACT population

The study population consists of 2581 men and women aged 65 or greater, in the Seattle area.

Selection Criteria

Minimum age
65
Countries
  • United States of America
Territory
Seattle
Other Criteria

Participants with an existing diagnosis of dementia or those who were in a skilled nursing community were excluded.

Sources of Recruitment

Specific Population
  • Members of an association
Supplementary Information

Random sample of members of the Group Health Cooperative of Puget Sound

Sample Size

Number of Participants
2,581
Number of Participants with Biological Samples
2,581
Supplementary information about number of participants

Recruitment 1: 2581 participants

Recruitment 2: 811 participants

Recruitment 3: Seeks to maintain population of approximately 2000 participants (ongoing)

Data Collection Events

# Name Data sources Data sources - Biosamples Start End
0 ACT - Recruitment 1
  • Questionnaires
  • Biosamples
  • Blood
1994 1996
1 ACT - Follow-up
  • Questionnaires
  • Cognitive measures
  • Physical measures
1996 2014
2 ACT - Recruitment 2
  • Questionnaires
  • Biosamples
  • Blood
2000 2002
3 ACT - Recruitment 3
  • Questionnaires
  • Biosamples
  • Blood
2004 2014

Participating Studies

Acronym Name Study design Countries

Harmonization Initiatives Included

Acronym Name

Datasets

Name Data Collection Events Variables

Areas of Information Collected

Socio-demographic and economic characteristics
Death
Lifestyle and behaviours
Physical measures and assessments
Birth, pregnancy and reproductive health history
Laboratory measures
Perception of health, quality of life, development and functional limitations
Cognition, personality and psychological measures and assessments
Diseases
Life events, life plans, beliefs and values
Symptoms and signs
Preschool, school and work life
Medication and supplements
Social environment and relationships
Non-pharmacological interventions
Physical environment
Health and community care services utilization
Administrative information

Variables Content Summary

Areas of Information Collected
No Areas of Information Collected
No Scales Collected
Areas of Information Collected per per Population and Data Collection Event
No Areas of Information Collected
No Scales Collected

Networks

Acronym Name Harmonization Initiatives Individual Studies
Last Update: 2026-04-27T09:39:16.812