DOI: 10.3886/icpsr36840.v13
title: Population Assessment of Tobacco and Health (PATH) Study [United States] Biomarker Restricted-Use Files
title: Version 13

description: The Population Assessment of Tobacco and Health (PATH) Study is a collaboration between the National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), and the Center for Tobacco Products (CTP), Food and Drug Administration (FDA). The study was launched in 2011 to inform the FDA's tobacco regulatory activities under the Family Smoking Prevention and Tobacco Control Act (TCA). For Wave 1 (baseline), the PATH Study sampled over 150,000 mailing addresses across the United States to create a national sample of tobacco users and non-users, yielding interviews with 45,971 adult and youth respondents. 45,971 adults and youth constitute the first (baseline) wave, Wave 1, of data collected by this longitudinal cohort study. These 45,971 adults and youth along with 7,207 "shadow youth" (youth ages 9 to 11 sampled at Wave 1) make up the 53,178 participants that constitute the Wave 1 Cohort. Respondents are asked to complete an interview at each follow-up wave. Youth who turn 18 by the current wave of data collection are considered "aged-up adults" and are invited to complete the Adult Interview. Additionally, "shadow youth" are considered "aged-up youth" upon turning 12 years old, when they are asked to complete an interview after parental consent.At Wave 4, a probability sample of 14,098 adults, youth, and shadow youth ages 10 to 11 was selected from the civilian, noninstitutionalized population at the time of Wave 4. This sample was recruited from residential addresses not selected for Wave 1 in the same sampled PSUs and segments using similar within-household sampling procedures. This "replenishment sample" was combined for estimation and analysis purposes with Wave 4 adult and youth respondents from the Wave 1 Cohort who were in the civilian, noninstitutionalized population at the time of Wave 4. This combined set of Wave 4 participants, 52,731 participants in total, forms the Wave 4 Cohort.Please refer to the Restricted-Use Files User Guide that provides further details about children designated as "shadow youth" and the formation of the Wave 1 and Wave 4 Cohorts. Each adult respondent, who completed the interview at Wave 1, was asked to provide at least two biospecimens. Providing biospecimens was voluntary and was not a condition of participation. Respondents were asked to report their use of all nicotine-containing products during the 3-day period prior to the time of any biospecimen collection (Nicotine Exposure Questions (NEQs)) to facilitate interpretation of biomarker results. Of the 32,320 respondents who completed the adult interview at Wave 1, 21,801 (67.4 percent) provided a urine specimen and 14,520 (44.9 percent) provided a blood specimen. A sample of 11,522 adults who provided sufficient urine for the planned analyses were selected from a diverse mix of six tobacco product use groups representing never, current, and recent former (within 12 months) users of tobacco products. This group constitutes the Wave 1 Biomarker Core. Of the 11,522 adults, 7,159 also provided a blood specimen. All urine and blood specimens provided by the Wave 1 Biomarker Core were sent for laboratory analysis. Wave 1 Restricted-Use Biomarker Data Files (Biomarker RUF) consist of three different types of files: 2 Collection and NEQ files for Urine (DS1001) and Blood (DS1101) 2 Biomarker Weight files including variables for use in variance estimation for Urine (DS1021) and Blood (DS1121) 8 Urine Panels (DS1031 to DS1038), 4 Serum Panels (DS1131 to DS1134) and 1 Plasma Panel (DS1231) containing biomarker assay results. For Wave 2, urine biospecimens were requested from the Wave 1 Biomarker Core. Respondents were also asked to complete the NEQs prior to biospecimen collection. The Wave 2 Biomarker RUF consists of three different types of files: 1 Collection and NEQ file for Urine (DS2001) 2 Biomarker Weight files including variables for use in variance estimation for Urine (DS2021) and F2PG2a (DS2022) 8 Urine Panels (DS2031 to DS2038) containing biomarker assay results. For Wave 3, urine biospecimens were requested from the Wave 1 Biomarker Core. Respondents were also asked to complete the NEQs prior to biospecimen collection. The Wave 3 Biomarker RUF consists of three different types of files: 1 Collection and NEQ file for Urine (DS3001) 2 Biomarker Weight files including variables for use in variance estimation for Urine (DS3021 and DS3022) 6 Urine Panels (DS3032 to DS3037) containing biomarker assay results. Additional panel(s) will be added at a later date. For Wave 4, urine biospecimens were requested from the Wave 1 Biomarker Core. Respondents were also asked to complete the NEQs prior to biospecimen collection. The Wave 4 Biomarker RUF consists of three different types of files: 1 Collection and NEQ file for Urine (DS4001) 2 Biomarker Weight files including variables for use in variance estimation for Urine (DS4021 and DS4022) 5 Urine Panels (DS4032, DS4033, DS4035, DS4036 and DS4037) containing biomarker assay results. Additional panel(s) will be added at a later date. References to the collection of biospecimens will be specified by the collected specimen, i.e., urine and (whole) blood. However, references to biomarker analyses and analytes will be specified by the type of matrix (serum, plasma, or urine) used for the analysis.
description: The Population Assessment of Tobacco and Health (PATH) Study is a longitudinal cohort study on tobacco use behavior, attitudes and beliefs, and tobacco-related health outcomes among an estimated 46,000 adults and youth in the United States. The study's primary objectives are to: <strong>Objective 1:</strong> Identify and explain between-person differences and within-person changes in tobacco-use patterns, including the rate and length of use by specific product type and brand, product/brand switching over time, uptake of new products, and dual- and poly-use of tobacco products (i.e., use of multiple products within the same time period and switching between multiple products). <strong>Objective 2:</strong> Identify between-person differences and within-person changes in risk perceptions regarding harmful and potentially harmful constituents, new and emerging tobacco products, filters and other design features of tobacco products, packaging, and labeling; and identify other factors that may affect use, such as social influences and individual preferences. <strong>Objective 3:</strong> Characterize the natural history of tobacco dependence, cessation, and relapse, including readiness and self-efficacy to quit, motivations for quitting, the number and length of quit attempts, and the length of abstinence related to various tobacco products. <strong>Objective 4:</strong> Update the comprehensive baseline and subsequent waves of data on tobacco-use behaviors and related health conditions, including markers of exposure and tobacco-related disease processes identified from the collection and analysis of biospecimens, to assess between-person differences and within-person changes over time in health conditions potentially related to tobacco use, particularly with use of new and different tobacco products, including modified-risk tobacco products. <strong>Objective 5:</strong> Assess associations between TCA-specific actions and tobacco-product use, risk perceptions and attitudes, use patterns, cessation outcomes, and tobacco-related intermediate endpoints (e.g., biomarkers of exposure and biomarkers related to disease). Analyses will attempt to account for other potential factors, such as demographics, local tobacco-control policies, and social, familial, and economic factors, that may influence the observed patterns. <strong>Objective 6:</strong> Assess between-person differences and within-person changes over time in attitudes, behaviors, exposure to tobacco products, and related biomarkers among and within population sub-groups identified by such characteristics as race-ethnicity, gender, and/or age, or by risk factors, such as pregnancy or co-occurring substance use or mental health disorders. <strong>Objective 7:</strong> To the extent to which sample sizes are sufficient, assess and compare samples of former and never users of tobacco products for between-person differences and within-person changes in relapse and uptake, risk perceptions, and indicators of tobacco exposure and disease processes. <strong>Objective 8:</strong> Use data from the PATH Study's baseline and follow-up waves on tobacco-use behaviors, attitudes, and related health conditions, including potential markers of exposure and related disease processes identified from the analysis of biospecimens, to screen and subsample respondents for participation in formative and/or nested studies conducted during and after the PATH Study's waves of data and biospecimen collection.
description: The study used a four-staged stratified sampling design to sample over 150,000 mailing addresses, yielding a Wave 1 (baseline) sample of 45,971 respondents (32,320 adults and 13,651 youth). Tobacco users and non-users, ages 12 years and older and in the civilian non-institutionalized household population were eligible for participation in the PATH Study. Field interviewers invited each adult respondent to voluntarily provide biospecimens as part of the study. Respondents were invited to "self-collect" a urine sample. Consenting respondents received $25 for providing one or both samples. At Wave 1, adults consenting to provide a blood sample were scheduled for a blood draw appointment with a phlebotomist at the respondent's home. The respondent received $25 for their time during this activity. Specific details about specimen collection and storage are contained in Chapter 2 of the Biomarker Restricted-Use Files User Guide.
description: The collection files for Urine (Wave 1: DS1001, Wave 2: DS2001, Wave 3: DS3001, Wave 4: DS4001) and Blood (Wave 1: DS1101, Wave 2 - Wave 4: N/A), contain data for the NEQs. Specifically, respondents are asked about their use of seven types of tobacco products: cigarettes, e-cigarettes, cigars (traditional, cigarillos, filtered), pipes, hookah, smokeless tobacco (snus pouches and other forms of smokeless tobacco), and dissolvable tobacco. They are also asked about their use of nicotine replacement therapies (NRT) such as a patch, gum, inhaler, pill, etc., and prescription drugs used for smoking cessation. Each section contains the same basic four questions: When was the product last used? What time of day was the product last used? What amount was used in the past 2 days? Was the product most recently used the same brand mentioned during the original (main) interview? (only asked when the NEQs are given in addition to the main questionnaire - i.e., at blood collection or &gt;4 hours after the main questionnaire) The Urine (Wave 1: DS1021, Wave 2: DS2021, Wave 3: DS3021 and DS3022, Wave 4: DS4021 and DS4022), F2PG2a (Wave 2:DS2022), and Blood (Wave 1: DS1121, Wave 2 - Wave 4: N/A) Biomarker Weight files contain: Complex design variables (stratum and cluster) Overall person weight 100 replicate weights Each Assay Panel for Urine (Wave 1: DS1031-DS1038, Wave 2: DS2031-DS2037, Wave 3: DS3032 - DS3037, Wave 4: DS4032, DS4033, DS4035, DS4036, DS4037), Serum (Wave 1: DS1131-DS1134, Wave 2 - Wave 4: N/A) and Plasma (Wave 1: DS1231, Wave 2 - Wave 4: N/A) contains the following information for each analyte included in the panel. Laboratory variables (e.g., date of analysis, run number, etc.) Imputed result value: The result value reported by the lab except results with values below the limit of detection (LOD) which are replaced with the LOD/(sqrt 2) Imputation flag: Designates which result values were below LOD Comment codes/text that provide additional observations about the analyzed sample Additional derived variables may also be included on some panels (e.g., total nicotine equivalents, etc.) See Appendix A of the Laboratory File Inventory for a list of chemical compounds analyzed within each of the panel codebooks for Wave 1 - Wave 4.
description: For Wave 1, there are two files containing weights for use in the analyses of biomarker data that reflect the complex PATH Study sample design. The final full-sample person-level weight for Urine is R01_A_URINEPWGT and for Blood it is R01_A_BLOODWGHT. Also, contained in these two files are 100 replicate weights and design variables (VARPSU and VARSTRAT) for use in variance estimation. For Wave 2, there are two files containing longitudinal weights: Urine weights and F2PG2a* weights. For use with all urine assays except F2PG2a, the final full-sample person-level weight is R02_A_URINEPWGT. Also, contained in this file are 100 replicate weights and design variables (VARPSU and VARSTRAT) for use in variance estimation. For F2PG2a data, separate weights were created where the final full-sample person level weight is R02_A_BC01_URF2WGT. Also contained in this file are the 100 replicate weights and design variabes (VARPSU and VARSTRAT) for use in variance estimation.*It is important to note that although the oxidative stress biomarker 8-isoprostane (F2PG2a) is a urine-based assay, only urine specimens from people who also provided blood specimens at Wave 1 were analyzed to ensure that sample sizes were roughly equivalent to blood-based assays. Therefore, the appropriate weight to use when analyzing the Wave 1 F2PG2a data is the blood weight. For follow-up waves in which F2PG2a data are available, separate biomarker weights are available for analysis of these data. For Wave 3, there are two files containing weights: the all-waves urine weights and the single-wave urine weights. The Wave 3 urine weights are for use in analyses including the Wave 3 urine biomarker data. The Wave 3 all-waves urine weights file contains weights for members of the Wave 1 Biomarker Core who completed the Wave 3 interview, provided a sufficient amount of urine for the planned analyses at Wave 3, and were also assigned a Wave 2 urine weight. The Wave 3 single-wave urine weights file contains weights for members of the Wave 1 Biomarker Core who completed the Wave 3 interview and provided a sufficient amount of urine for the planned analyses, regardless of their level of participation in the study at Wave 2. The Wave 3 all-waves weight is named R03_A_BC01A_URWGT. The Wave 3 single-wave weight is named R03_A_BC01S_URWGT. Each Wave 3 urine weights file also contains 100 replicate weights and design variables (VARPSU and VARSTRAT) for use in variance estimation.For Wave 4, there are two files containing weights: the all-waves urine weights and the single-wave urine weights. The Wave 4 urine weights are for use in analyses including the Wave 4 urine biomarker data. The Wave 4 all-waves urine weights file contains weights for members of the Wave 1 Biomarker Core who completed the Wave 4 interview, provided a sufficient amount of urine for the planned analyses at Wave 4, and were also assigned Wave 2 and Wave 3 urine weights. The Wave 4 single-wave urine weights file contains weights for members of the Wave 1 Biomarker Core who completed the Wave 4 interview and provided a sufficient amount of urine for the planned analyses, regardless of their level of participation in the study at Wave 2 or Wave 3. The Wave 4 all-waves weight is named R04_A_BC01A_URWGT. The Wave 4 single-wave weight is named R04_A_BC01S_URWGT. Each Wave 4 urine weights file also contains 100 replicate weights and design variables (VARPSU and VARSTRAT) for use in variance estimation. Detailed information on how these variables were created, and how and why they should be used is provided in the Biomarker Restricted-Use Files User Guide. The weighting procedures adjust for oversampling of population groups and non-response. <em><strong>ICPSR strongly recommends that users read and understand this section before analyzing the data to ensure correct use of these variables.</strong></em> Due to the subsampling of adults to determine the biospecimens sent for laboratory analysis, using the weights provided with the biomarker data makes the data nationally representative of tobacco users and nonusers in six tobacco product use groups only. These estimates can be described as representative of never, current, and recent former (within 12 months) users of tobacco products in the U.S. civilian, noninstitutionalized adult population at the time of Wave 1. At subsequent waves, weighted estimates of Wave # data are nationally representative of adults in the U.S. civilian, noninstitutionalized population that were never, current, or recent former (within 12 months) users of tobacco products at Wave 1 and who lived in the United States (and were not incarcerated) at Wave #.
description: Response Rates: A total of 32,320 adults completed an interview during Wave 1 of data collection. The collection rates of urine and blood provided by these 32,320 respondents were: Wave 1 urine specimen: 21,801; 67.4 percent Wave 1 blood specimen: 14,520; 44.9 percent Not all adults who provided a blood sample provided a urine sample, and some adults refused to provide both of the requested specimens. Table 2 in the Biomarker Restricted-Use Files User Guide gives a breakdown of the various combinations of samples provided by the 32,320 adult respondents. Among Wave 2 Adult Interview respondents, a subsample of continuing adults who provided urine at Wave 1 were asked to provide a urine specimen. Among the Wave 1 Biomarker Core, 9,996 completed a Wave 2 interview. The collection rate of urine specimens provided by the Wave 1 Biomarker Core at Wave 2 was 96.4 percent (a total of 9,640 collected). See the Laboratory File Inventory for more details. Among Wave 3 Adult Interview respondents, a subsample of continuing adults who provided urine at Wave 1 were asked to provide a urine specimen. Among the Wave 1 Biomarker Core, 9,462 completed a Wave 3 interview. The collection rate of urine specimens provided by the Wave 1 Biomarker Core at Wave 3 was 97.5 percent (a total of 9,227 collected). See the Laboratory File Inventory for more details. Among Wave 4 Adult Interview respondents, a subsample of continuing adults who provided urine at Wave 1 were asked to provide a urine specimen. Among the Wave 1 Biomarker Core, 8,817 completed a Wave 4 interview. The collection rate of urine specimens provided by the Wave 1 Biomarker Core at Wave 4 was 98 percent (a total of 8,641 collected). See the Laboratory File Inventory for more details.
description: A four-stage stratified area probability sample design was used in the PATH Study, with a two-phase design for sampling adults at the final stage. At the first stage, a stratified sample of geographical primary sampling units (PSUs) was selected, in which a PSU is a county or group of counties. For the second stage, within each selected PSU, smaller geographical segments were formed and then a sample of these segments was drawn. At the third stage, the sampling frame consisted of the residential addresses located in these segments. The fourth stage selected adults and youth from the sampled households identified at these addresses, with varying sampling rates for adults by age, race, and tobacco use status. Adults were sampled in two phases - Phase 1 sampling used information provided in the household screener and Phase 2 sampling used information provided by the adult in the Phase 2 screener at the beginning of the adult instrument. A stratified probability subsample of 11,522 adults who completed the Wave 1 adult interview and provided sufficient urine for the planned analyses (independently of whether they provided a blood specimen) was selected from a diverse mix of tobacco product users. This group constitutes the Wave 1 Biomarker Core. Of these 11,522 adults, 7,159 also provided a blood specimen. All urine and blood specimens provided by the Wave 1 Biomarker Core were sent for laboratory analysis. Please consult the Biomarker Restricted-Use Files User Guide for additional details about the subsampling. Wave 2 was the first follow-up wave for participants in Wave 1. At Wave 2, the PATH Study completed 28,362 Adult Interviews, but only those in the Wave 1 Biomarker Core were asked to provide urine for lab analysis. Of those who provided urine samples, 9,012 were shipped for lab analysis. See the Laboratory File Inventory for more details. Wave 3 was the second follow-up wave for participants in Wave 1. At Wave 3, the PATH Study completed 28,148 Adult Interviews, but only those in the Wave 1 Biomarker Core were asked to provide urine for lab analysis. Of those who provided urine samples, 8,643 were shipped for lab analysis. See the Laboratory File Inventory for more details. Wave 4 was the third follow-up wave for participants in Wave 1. At Wave 4, the PATH Study completed 27,757 Adult interviews with Wave 1 Cohort respondents, but only those in the Wave 1 Biomarker Core were asked to provide urine for lab analysis. Of those who provided urine samples, 8,333 were shipped for lab analysis. See the Laboratory File Inventory for more details.
description: Datasets: DS0: Study-Level Files DS4032: Wave 4: Urine Panel - Enzymatic Urinary Creatinine (CREAU) DS4033: Wave 4: Urine Panel - Metals (Metals) DS4035: Wave 4: Urine Panel - Tobacco-Specific Nitrosamines (TSNA) DS4036: Wave 4: Urine Panel - Urinary Nicotine Metabolites (Cotinine and Hydroxycotinine) (UNICM) DS4037: Wave 4: Urine Panel - Volatile Organic Compounds Metabolites (VOCM) DS1031: Wave 1: Urine Panel - Speciated Arsenic (AsSpec) DS1032: Wave 1: Urine Panel - Enzymatic Urinary Creatinine (CREAU) DS1033: Wave 1: Urine Panel - Metals (Metals) DS1034: Wave 1: Urine Panel - Hydroxy Polycyclic Aromatic Hydrocarbons (PAH) DS1035: Wave 1: Urine Panel - Tobacco-Specific Nitrosamines (TSNA) DS1036: Wave 1: Urine Panel - Urinary Nicotine Metabolites (Cotinine and Hydroxycotinine) (UNICM) DS1101: Wave 1: Blood Collection and NEQ Data DS1037: Wave 1: Urine Panel - Volatile Organic Compounds Metabolites (VOCM) DS3021: Wave 3: Urine Biomarker Weights - All-Waves Urine Weights DS3022: Wave 3: Urine Biomarker Weights - Single-Wave Urine Weights DS1038: Wave 1: Urine Panel - Oxidative Stress (F2PG2a) DS1231: Wave 1: Plasma Panel - Fibrinogen Activity (Clauss) (Fibro) DS2001: Wave 2: Urine Collection and NEQ Data DS3032: Wave 3: Urine Panel - Enzymatic Urinary Creatinine (CREAU) DS3033: Wave 3: Urine Panel - Metals (Metals) DS3034: Wave 3: Urine Panel - Hydroxy Polycylic Aromatic Hydrocarbons (PAH) DS3035: Wave 3: Urine Panel - Tobacco-Specific Nitrosamines (TSNA) DS3036: Wave 3: Urine Panel - Urinary Nicotine Metabolites (Cotinine and Hydroxycotinine) (UNICM) DS3037: Wave 3: Urine Panel - Volatile Organic Compounds Metabolites (VOCM) DS1121: Wave 1: Blood Biomarker Weights DS4001: Wave 4: Urine Collection and NEQ Data DS2021: Wave 2: Urine Biomarker Weights DS2022: Wave 2: Urine Biomarker Weights - Oxidative Stress (F2PG2a) Weights DS1001: Wave 1: Urine Collection and NEQ Data DS1131: Wave 1: Serum Panel - Cotinine and Hydroxycotinine (SCOT) DS1132: Wave 1: Serum Panel - High-Sensitivity C-Reactive Protein (hsCRP) DS1133: Wave 1: Serum Panel - Interleukin 6 (IL6) DS1134: Wave 1: Serum Panel - Soluble Intercellular Adhesion Module (sICAM) DS2031: Wave 2: Urine Panel - Speciated Arsenic (AsSpec) DS2032: Wave 2: Urine Panel - Enzymatic Urinary Creatinine (CREAU) DS2033: Wave 2: Urine Panel - Metals (Metals) DS2034: Wave 2: Urine Panel - Hydroxy Polycyclic Aromatic Hydrocarbons (PAH) DS2035: Wave 2: Urine Panel - Tobacco-Specific Nitrosamines (TSNA) DS2036: Wave 2: Urine Panel - Urinary Nicotine Metabolites (Cotinine and Hydroxycotinine) (UNICM) DS4021: Wave 4: Urine Biomarker Weights - All-Waves Urine Weights DS2037: Wave 2: Urine Panel - Volatile Organic Compounds Metabolites (VOCM) DS2038: Wave 2: Urine Panel - Oxidative Stress (F2PG2a) DS4022: Wave 4: Urine Biomarker Weights - Single-Wave Urine Weights DS3001: Wave 3: Urine Collection and NEQ Data DS1021: Wave 1: Urine Biomarker Weights
description: Adult (age 18 and older) never, current, and recent former (within 12 months) users of tobacco products in the civilian, non-institutionalized household population of the United States at the time of Wave 1 (September 12, 2013 - December 14, 2014). Smallest Geographic Unit: None
description: audio computer-assisted self interview (ACASI); computer-assisted personal interview (CAPI); paper and pencil interview (PAPI)The PATH Study Data User Forum allows researchers using the PATH Study data (public-use and restricted-use files) to communicate with each other, including having an opportunity to ask and answer questions. Announcements, data releases and updates, new publications, upcoming events, and other information for PATH Study data users will also be posted to the forum.Data are provided via ICPSR's Virtual Data Enclave (VDE) where researchers work with data stored on secure ICPSR servers. Researchers cannot possess physical copies of the data; however, upon review by ICPSR, they may request permission to access selected output outside the virtual environment. See the Access Notes to apply for access. Researchers are also encouraged to read the VDE Guide.The data currently available are the Wave 1, Wave 2, Wave 3, and Wave 4 restricted-use biomarker data files. Additional Wave 3 and Wave 4 restricted-use biomarker panel(s) are forthcoming in subsequent release(s).Further information about the biospecimens collected in Wave 1 - Wave 4 is available in the PATH Study Biomarker Restricted-Use Files User Guide. Researchers interested in accessing PATH Study biospecimens for biospecimen research should refer to the PATH Study Biospecimen Access Program page. This page provides instructions on applying for access, the schedule for reviewing applications, and frequently asked questions about the program.The Restricted-Use Master Linkage File (RUF-MLF) is available in the Master Linkage File collection (ICPSR 38008). The RUF-MLF (DS0002) includes indicator variables for the availability of interview data, weights, state identifier data, tobacco Universal Product Code (UPC) data, and biomarker data for each participant. It also includes variables that indicate availability of biospecimens through the Biospecimen Access Program (BAP). The RUF-MLF can help analysts identify which Restricted-Use files contain data for a particular participant (or set of participants).The data files contain a person-level (PERSONID) variable to link participant IDs across files (e.g., linking Wave 1 adult questionnaire data with Wave 1 biomarker data) and across waves (e.g., linking Wave 1 and Wave 2 biomarker data). The values in this variable are random and contain no direct or indirect personally identifiable information. Please review Chapter 5 in the Biomarker Restricted-Use Files User Guide for information and programming code on linking files. The files are sorted by the variable PERSONID.The questionnaires in this collection have been annotated for analytic purposes. Users are advised that most but not all information contained in the questionnaires is duplicated in the question text used in the codebooks. Some of the longer programming instructions were not incorporated into the question text. In these instances, the question text includes a note for the user to read the full programming instructions in the corresponding section of the questionnaire. Derived and imputed variables contain the algorithms used in the creation of these variables. Users are advised to refer to the Biomarker Restricted-Use Files User Guide and annotated questionnaires when reviewing the codebooks.In accordance with the study's informed consent, information is suppressed for individuals who withdraw from the PATH Study. Their information was recoded to a special missing value, designated as -97777.The PATH Study's documentation is available for your use and may be reproduced in whole or in part without permission from NIH's National Institute on Drug Abuse or FDA's Center for Tobacco Products. Citation of the source is appreciated.Additional background information including answers to frequently asked questions can be found in the Researchers section of the PATH Study series page.The Biomarker Restricted-Use Files User Guide provides an overview of the biospecimen collection process. The User Guide also covers such topics as subsampling of adults for biomarker analysis, weighting, and programming syntax to run common statistics and link the files. Researchers are encouraged to use the information in the User Guide for their publications, with the following citation: United States Department of Health and Human Services. National Institutes of Health. National Institute on Drug Abuse, and United States Department of Health and Human Services. Food and Drug Administration. Center for Tobacco Products. Population Assessment of Tobacco and Health (PATH) Study [United States] Biomarker Restricted-Use Files, User Guide. ICPSR36840-v8 Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2020-03-05. https://doi.org/10.3886/ICPSR36840.userguide_restricted The data for the PATH Study were collected and prepared by Westat. The contract numbers under which they performed their work are HHSN271201100027C and HHSN271201600001C.