Uniform Data Set version 4
UDSv4 - Template

United States

Reference ID

USDv4

Producer(s)

National Alzheimer’s Coordinating Center (NACC) and the NIA-funded ADRC network

Collections

Clinical Trial

Metadata

DDI/XML JSON

Created on

Jul 02, 2026

Last modified

Jul 07, 2026

Page views

13661

Study Description
Data Dictionary

25a. Sleep apnea (i.e., obstructive, central, mixed or complex sleep apnea) (primary/contributing/non-contributing) (apneadxif)

Data file: UDSv4TemplateForXMLD_2026-04-14_0731.REDCap.xml

Overview

Valid: 60

Range: -

Format:

Questions and instructions

Question pretext

[loc_apneadx(1)] = 1

Categories

Value	Category	Cases
1	Primary	29	48.3%
2	Contributing	28	46.7%
3	Non-contributing	3	5%

Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.

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