• 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
  • SMQ020 - Smoked at least 100 cigarettes in life
  • SMQ040 - Do you now smoke cigarettes?
  • SMD641 - # days smoked cigs during past 30 days
  • SMD650 - Avg # cigarettes/day during past 30 days
  • SMD100MN - Cigarette Menthol indicator
  • SMQ621 - Cigarettes smoked in entire life
  • SMD630 - Age first smoked whole cigarette
  • SMAQUEX2 - Questionnaire Mode Flag

National Health and Nutrition Examination Survey

August 2021-August 2023 Data Documentation, Codebook, and Frequencies

Smoking - Cigarette Use (SMQ_L)

Data File: SMQ_L.xpt

First Published: September 2024

Last Revised: NA

Component Description

This smoking - cigarette use questionnaire (variable name prefix SMQ) provides a history of cigarette smoking, age at initiation, past 30-day use, and cigarette type. Since 1999, SMQ questionnaire content has varied; this data set has fewer variables than past cycles. 

Eligible Sample

All participants aged 12 years and older were eligible. Participants aged 12-17 answered questions on their own; interviews requiring proxy informants or interpreters were not administered.

Interview Setting and Mode of Administration

For adults aged 18 years or older, this questionnaire was asked by trained interviewers using the Computer-Assisted Personal Interview (CAPI) system in the participant’s home or by telephone.  For youth aged 12-17 years, 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 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. Interviewers were required to audio-record interviews. The recorded interviews were reviewed by interviewer supervisors and NCHS staff.

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

Several questions were dropped in NHANES August 2021-August 2023 and are not included in this data file, including SMQ030, SMQ050, SMQ055, SMQ057, SMQ078, SMQ653, SMQ657, SMQ671. 

Questions varied by target age; youths 12-17 years were asked fewer questions than adults 18 years and older. Analysts are advised to carefully review skip patterns, and target ages for this question series, and to combine and re-code responses to account for the full target sample. Persons who were not asked a question due to a skip pattern were coded as missing (“.”). If skip patterns are not considered, estimates may be based on a portion rather than on the entire population. For example, to determine current adult cigarette smoking status (18+ years), responses to the preliminary question (SMQ.020) on ‘100 cigarettes in lifetime,’ with responses to the follow-up question on ‘now smokes cigarette’ (SMQ.040) must be considered. 

Related questions on cigarette and tobacco use are located in the SMQRTU, SMQFAM 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.

Codebook and Frequencies