The NHANES program suspended field operations in March 2020 due to the coronavirus disease 2019 (COVID-19) pandemic. As a result, data collection for the NHANES 2019-2020 cycle was not completed and the collected data are not nationally representative. Therefore, data collected from 2019 to March 2020 were combined with data from the NHANES 2017-2018 cycle to form a nationally representative sample of NHANES 2017-March 2020 pre-pandemic data. These data are available to the public. Please refer to the Analytic Notes section for more details on the use of the data.
The Drug Use questionnaire (variable name prefix DUQ) focuses on lifetime and current use of marijuana or hashish, cocaine, heroin, and methamphetamine, as well as intravenous use of these and other drugs.
Participants aged 12 to 59 years, in the NHANES 2017-March 2020 pre-pandemic sample, were eligible; however, only data from participants aged 18-59 are included in this file available through the NCHS Research Data Center (RDC). Data collected for participants aged 12-17 years are available in a separate file through the RDC. Mentally impaired participants, or participants who were unable to understand English, Spanish, Korean, Vietnamese, or Chinese (traditional/Mandarin, simplified/Mandarin, and traditional/Cantonese) were excluded from the DUQ.
Interview Setting and Mode of Administration
The DUQ was administered at the Mobile Examination Center (MEC) during the MEC Interview. For participants aged 12 to 59, questions were self-administered using the Audio Computer-Assisted Self-Interview (ACASI) system.
The ACASI was conducted in one of the following languages: English, Spanish, Korean, Vietnamese, or Chinese (traditional/Mandarin, simplified/Mandarin, and traditional/Cantonese).
The ACASI enables participants both to hear questions through headphones and read questions on the computer screen. Participants moved at their own speed and touched the screen to indicate their responses. No proxy respondents or translators were used during the ACASI.
The NHANES 2017-2018 and 2019-2020 questionnaires are available on the NHANES website.
Quality Assurance & Quality Control
For details on the QA/QC process for this component, please refer to the MEC Interviewer Procedures manual on the NHANES website.
Data Processing and Editing
The data were edited for completeness, consistency, and illogical values.
To decrease the risk of disclosure, additional “bottom” summary codes were implemented for the variable DUQ210. For the age of first use of marijuana, participants who reported an age less than or equal to 11 years were coded as “11 years or younger.” In addition, the variable DUD380F includes participants who reported injecting steroids or “any other drug” (i.e., other than cocaine, heroin, or methamphetamine, which are asked about separately) using a needle. In prior cycles, these frequencies were available separately in variables DUQ380D and DUQ380E, respectively.
To make the data collected in the NHANES 2017-2018 cycle compatible with those collected in the NHANES 2019-March 2020, changes were made to both datasets.
For 2017-2018, the variables DUQ220Q and DUQ220U were used to backfill DUQ230 for ever users of marijuana. Respondents who reported use of marijuana more than 30 days, 4 weeks, 1 month or 1 year ago were recoded to 0 for DUQ230. Those who reported “Refused” or “Don’t Know” to DUQ220Q/DUQ220U were recoded to 777 or 999, respectively, for DUQ230.
For data collected in 2019-March 2020, DUQ005 was renamed to DUQ210 and used to create DUQ200. Respondents who reported an age of first use of marijuana for DUQ005/DUQ210 were coded as 1 for DUQ200, those who reported never use were coded as 2, and “Refused” and “Don’t Know” were coded as 7 and 9, respectively. After creating the variable DUQ200, DUQ210 was set to missing for respondents who didn’t report an age of first use of marijuana. The variables DUQ250, DUQ290 and DUQ330 were used to create DUQ240. Respondents who reported “Yes” to DUQ250, DUQ290 or DUQ330 were coded as 1 for DUQ240, those who reported “No” to DUQ250, DUQ290 and DUQ330 were coded as 2, those who reported “Refused” to DUQ250, DUQ290 or DUQ330 were coded as 7, and those who reported “Don’t Know” to DUQ250, DUQ290 or DUQ330 were coded as 9. After creating DUQ240, the variables DUQ250, DUQ290, and DUQ330 were set missing for respondents not coded as “Yes” for ever use of cocaine, crack cocaine, heroin, or methamphetamine.
The COVID-19 pandemic required suspension of NHANES 2019-2020 field operations in March 2020 after data were collected in 18 of the 30 survey locations in the 2019-2020 sample. Data collection was cancelled for the remaining 12 locations. Because the collected data from 18 locations were not nationally representative, these data were combined with data from the previous cycle (2017-2018) to create a 2017-March 2020 pre-pandemic data file. A special weighting process was applied to the 2017-March 2020 pre-pandemic data file. The resulting sample weights in the demographic data file should be used to calculate estimates from the combined cycles. These sample weights are not appropriate for independent analyses of the 2019-2020 data and will not yield nationally representative results for either the 2017-2018 data alone or the 2019-March 2020 data alone. Please refer to the NHANES website for additional information for the NHANES 2017-March 2020 pre-pandemic data, and for the previous 2017-2018 public use data file with specific weights for that 2-year cycle.
Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.
Since the questionnaire was asked in the MEC, the MEC sample weights should be used in the analysis.