Adult Changes in Thought Study

The ACT Data Repository

The ACT Data Repository is broadly defined as all data related to participants in the Adult Changes in Thought (ACT) Study. At a high level, data sources that make up the ACT Data Repository include data collected directly by the ACT Study — such as self-reported risk factor data, cognitive testing data, and research diagnoses produced by the ACT Study team in the course of working directly with participants — along with data from a number of other sources, as outlined in the table below. This table encapsulates the major categories of data that comprise the ACT Data Repository, along with a high-level description of each data domain.

ACT Study Visit Data
ACT participants complete an ACT Study visit where standardized measures and forms are collected approximately every 2 years (biennially) until dementia diagnosis, death, or study withdrawal. If a participant receives a dementia diagnosis, they begin an annual visit track. 

Electronic Health Record & Utilization Data 
Because ACT participants are selected from among Kaiser Permanente Washington members, the ACT Study can link to information on health plan administrative data, clinical encounter and utilization data, pharmacy dispensings, laboratory measures, and other medical record data on ACT participants.

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Medical Record Abstraction Data
Some medical record data is not available for electronic linkage. As a result, the ACT Study has been conducting an ongoing manual medical record review to abstract additional elements for potential use in future research. These additional data elements, provided by the ACT Life Course Core, are only available on a select sample of ACT participants.

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Neuropathology Data
Some ACT participants consent to brain autopsy upon death, generously donating their brain for neuropathological assessment by the ACT Neuropathology Core. After autopsy, complete neuropathological assessments are completed, and data elements derived from those assessments of ACT participant brains are collected and stored. The ACT neuropathology dataset contains measures from ACT participants who died and for whom neuropathological assessment was completed.

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Neuroimaging Data
Processed measures from brain magnetic resonance imaging (MRI) exist for some participants in the ACT Study. These measures, provided by the ACT Neuroimaging Core, come from a mix of clinical MRI scans that were abstracted from medical records of consenting ACT participants and research MRI scans that were conducted among select samples of participants.

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Activity Monitoring Device (Accelerometry) Data
In 2016, qualifying current ACT participants were invited to participate in an activity-monitoring sub-study (ACT-AM). As part of this study, participants wore an activPAL or ActiGraph accelerometer, or both, and completed daily sleep logs. Data collection has been ongoing, with expansion to a larger number of participants and addition of a sleep watch planned for the future.

Genetic, Biomarker, or Other Specimen Data
DNA samples were and are collected from ACT participants. Apolipoprotein E (APOE) genotype is routinely obtained from these samples and used in most ACT analyses. There are also plans to obtain new blood samples from participants at study visits. Data generated from these blood samples — including plasma biomarkers — will be part of the ACT Data Repository in the future.

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Historical Life Course & Social Determinants of Health Data
In the future, the ACT Study plans to conduct a one-time survey administered to participants focused on early life-course exposures, as well as to enhance use of geocoded and U.S. Census-linked data.

Data Generated from ACT-Affiliated Research Studies 
This includes a variety of data types not collected as part of any of the data streams above, added for the explicit purpose of answering a research question funded by an ancillary grant working with the ACT cohort. Examples include the ACT Air Pollution study, various traumatic brain injury projects, and ACT-eye.