• Component Description
• Eligible Sample
• Interview Setting and Mode of Administration
• Quality Assurance & Quality Control
• Data Processing and Editing
• Analytic Notes
• Codebook
  • SEQN - Respondent sequence number
  • SLQ300 - Usual sleep time on weekdays or workdays
  • SLQ310 - Usual wake time on weekdays or workdays
  • SLD012 - Sleep hours - weekdays or workdays
  • SLQ320 - Usual sleep time on weekends
  • SLQ330 - Usual wake time on weekends
  • SLD013 - Sleep hours - weekends
  • SLQ030 - How often do you snore?
  • SLQ040 - How often do you snort or stop breathing
  • SLQ050 - Ever told doctor had trouble sleeping?
  • SLQ120 - How often feel overly sleepy during day?

National Health and Nutrition Examination Survey

2017-2018 Data Documentation, Codebook, and Frequencies

Sleep Disorders (SLQ_J)

Data File: SLQ_J.xpt

First Published: February 2020

Last Revised: NA

Component Description

The sleep disorders (variable name prefix SLQ) data set has questions on sleep habits and disorders. In 2017-2018, two questions on usual sleep and wake times on weekend were added.

Eligible Sample

All participants aged 16 and older were eligible.

Interview Setting and Mode of Administration

These questions were asked in the home, by trained interviewers, using the Computer-Assisted Personal Interview (CAPI) system.

Quality Assurance & Quality Control

The CAPI system is programmed with limited built-in consistency checks to reduce data entry errors. Additional edits were conducted post-data collection as described in "Data Processing and Editing."

Data Processing and Editing

Edits were made to ensure completeness, consistency, and analytic usefulness of the data. Approximately 3% of audio recording interviews were reviewed to validate unusual times for SLQ300, SLQ310, SLQ320, SLQ330 resulting in very long or short hours of sleep.
The most common entry errors were confusing PM and AM hours; (i.e., 12 PM instead of 12 AM), and the transposition of digits when minutes were recorded (i.e., ‘03’ for ‘30’). Comments from interviewers also were considered. Edits were made to approximately 45% of the reviewed records.

Summary variables for usual number of hours of sleep on weekdays (SLD012) and weekends (SLD013) were derived from reported times. Hours were rounded to the nearest half hour. For SLD012 and SLD013, hours of ‘less than 3’ and ‘more than 14’ were grouped and recoded with these value labels. For participants with either of these low or high hours, times in SLQ300, SLQ310, SLQ320, SLQ330 were set to missing to minimize disclosure risks.

Analytic Notes

Please refer to the NHANES Analytic Guidelines and the online NHANES Tutorial for further details on the use of sample weights and other analytic issues.

SLQ300, SLQ310, SLQ320, SLQ330 were formatted as character variables for time in hours and minutes. Times between 00:00 (midnight) and 11:59 in the morning indicate AM. Times between 12:00 (noon) and 11:59 at night indicate PM.

SLD012 (hours of sleep weekdays)/workdays) and SLD013 (hours of sleep weekends/non- workdays) are derived variables, calculated from reported usual bed time (SLQ300 and SLQ320) and wake time (SLQ310 and SLQ330) during main sleeping period (night or day). Respondents reporting that they woke up periodically or that they slept for very short periods of times at night or during the day were asked to report hours of their main sleeping period. Therefore, SLD012 and SLD013 may not represent the total hours of sleep during a 24 hour period, including naps or other periods of sleep. If either sleep and wake time was not reported, then SLD012 was not calculated. See “Data Processing and Editing” regarding the coding of short or long hours of sleep.

Codebook and Frequencies