Component Description
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.
This smoking - cigarette use (prefix SMQ) data set provides a history of cigarette smoking, age at initiation, past 30-day use, time to first cigarette, cigarette type, and quit attempts. Since 1999, question content has varied, and some cycles have included questions on cigarette brand and on the use of other tobacco products. This data set combines only the questions that were in both the 2017-2018, and 2019- March 2020 cycles.
Eligible Sample
All participants aged 12 years and older in the NHANES 2017-March 2020 pre-pandemic sample were eligible. For participants aged 12-17, no proxy interviews were eligible.
Interview Setting and Mode of Administration
For adults aged 18 years or older, questions were asked, in the home, by trained interviewers using the Computer-Assisted Personal Interview (CAPI) system. For youth aged 12-17 years, the questions were asked at the Mobile Examination Center (MEC) during the MEC Interview using the Audio Computer-Assisted Self-Interview (ACASI) system, in English and Spanish only.
Quality Assurance & Quality Control
The CAPI and ACASI systems are programmed with built-in consistency checks to reduce data entry errors. CAPI also uses online help screens to assist interviewers in defining key terms used in the questionnaire.
Data Processing and Editing
Edits were made to ensure completeness, consistency, and analytic usefulness of the data. A variable, SMAQUEX was created as a flag to designate each interview mode and age group.
Analytic Notes
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. 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 interview or examination sample weights in the demographic data file should be used to calculate estimates for this combined data file. 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.
Analysts are advised to carefully review skip patterns, and target ages for this question series, and to re-code or create new variables, as needed. Persons who are not asked a question due to a skip pattern are coded as missing (“.”). Variables vary by target age; some are based on all ages 12+ years, others are only for youths 12-17 years. If skip patterns are not considered, estimates may be based on a portion rather than on the entire population. For example, to determine current cigarette smoking status (18+ years), combine the responses for the preliminary question (SMQ.020) on ‘100 cigarettes in lifetime,’ with responses to the follow-up question on ‘now smokes cigarette’ (SMQ.040)’.
Related questions on cigarette and tobacco use are located in the SMQRTU, SMQFAM and SMQSHS data files. Biomarkers for tobacco exposure including serum cotinine, are found in NHANES laboratory data files.
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.