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 smoking and tobacco use – secondhand smoke questionnaire provides information on exposure to other persons’ cigarette and tobacco smoke in various indoor environments over the past 7 days. A new question was added in 2017-2018 to capture potential exposure to second aerosol from e-cigarettes and other electronic smoking devices.
All participants in the NHANES 2017-March 2020 pre-pandemic sample were eligible.
Interview Setting and Mode of Administration
The questions were asked as part of the Sample Person questionnaire, in the home, using the Computer-Assisted Personal interview (CAPI) system for persons aged 18+ years, and to proxy respondents for persons aged 0-11 years. Youth aged 12-17 were asked the questions using CAPI during the MEC Interview.
Quality Assurance & Quality Control
The CAPI system is 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.
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 examination or interview 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.
In the questionnaire, participants are asked about each environment where exposure to secondhand smoke may have occurred (job, bar, restaurant, other homes, other indoor place) a filter question was asked to determine first whether the respondent was in this location during the past 7 days. When the response was “no,” the respondent was not asked the follow-up question about exposure to smokers at the location. Only adults 18+ years were asked about tobacco exposure in their workplaces and in bars. The variable SMAQUEX designates the age group and mode of the questionnaire.
Note that only youth aged 12-17 were asked these questions in the MEC, which was at the same time that phlebotomy and urine collection occurred for laboratory measurements.
Questions that identify persons who smoke inside the home are found in SMQFAM. Questions on cigarette smoking and other tobacco use are located in SMQ and SMQRTU data files. Biomarkers of tobacco exposure, including serum cotinine, are found in the 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.