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Description of available data

The research populations covered by the NACC database

NACC serves as a repository for data collected at approximately 29 Alzheimer's Disease Centers (ADCs) throughout the United States. The ADCs conduct clinical and biomedical research on Alzheimer's disease and related disorders. Centers enroll their study subjects in various ways, including referral from clinicians, self-referral by patients themselves or concerned family members, active recruitment through community organizations, and volunteers who wish to contribute to research on various types of dementia. Most centers also enroll volunteer control subjects. Study subjects at each center are best regarded as a case series, not necessarily representing all cases of disease in a defined population.

The NACC database

The three main data research sets available from NACC are summarized in the table below. NACC also archives several other, more specialized data sets, as described below.

 

  Minimum data set
(MDS)
Uniform Data Set (UDS)
(LONGITUDINAL)
Neuropathology
Data Set (NP)
Years covered 1984 - 2005 Sept. 2005 - present 1984 - present
Study subjects Enrollees followed at ADCs
(with or without dementia)
Enrollees followed at ADCs
(with or without dementia)
Subjects who died and underwent autopsy
Approx. # of subjects* 74,397 30,585 14,035
Approx. # of variables 67 725 85
Method of
data collection
Mainly abstracted retroactively from ADC medical records Collected prospectively by clinicians, neuropsychologists, and other ADC research personnel, using up to 18 standardized forms at each visit.
Some forms also have Spanish-language and telephone versions.
Standardized neuropathology form, completed by neuropathologist
Time period covered for each subject Mainly status on last ADC visit; some variables also capture initial-visit status Initial visit and each annual follow-up visit, plus milestones such as
death or dropout
Status of brain at autopsy
Topics covered
(brief list)
Demographics, cognitive status, clinical dementia diagnosis, selected clinical manifestations, comorbid conditions, MMSE score, vital status, primary neuropathological diagnosis (if died and had brain autopsy) Sociodemographics on subject and informant, family history, dementia history, neurological exam findings, functional status, neuropsych-ological test results, clinical diagnosis, whether imaging testing done, ApoE genotype Demographics, date of death, primary and secondary neuropathological diagnoses, presence/absence of neuropathological features of most major dementias, APOE genotype, brain weights
Publications describing
data set
Beekly, 2004 Morris, 2006
Beekly, 2007
Weintraub, 2009
Beekly, 2004
Links to
data forms, guidebooks, and DEDs
MDS data form, guidebook and data element dictionary UDS data forms, guidebooks, and data element dictionaries NP data form, guidebook, and data element dictionary

*as of the June 1, 2014 data freeze