Given the rapid increase in the popularity of e-cigarettes and the paucity of associated longitudinal health-related data, the need to assess the potential risks of long-term use is essential.
To compare exposure to nicotine, tobacco-related carcinogens, and toxins among smokers of combustible cigarettes only, former smokers with long-term e-cigarette use only, former smokers with long-term nicotine replacement therapy (NRT) use only, long-term dual users of both combustible cigarettes and e-cigarettes, and long-term users of both combustible cigarettes and NRT.
The following 5 groups were purposively recruited: combustible cigarette–only users, former smokers with long-term (≥6 months) e-cigarette–only or NRT-only use, and long-term dual combustible cigarette–e-cigarette or combustible cigarette–NRT users (n = 36 to 37 per group; total n = 181).
Sociodemographic and smoking characteristics were assessed. Participants provided urine and saliva samples and were analyzed for biomarkers of nicotine, tobacco-specific N-nitrosamines (TSNAs), and volatile organic compounds (VOCs).
After confounders were controlled for, no clear between-group differences in salivary or urinary biomarkers of nicotine intake were found. The e-cigarette–only and NRT-only users had significantly lower metabolite levels for TSNAs (including the carcinogenic metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol [NNAL]) and VOCs (including metabolites of the toxins acrolein; acrylamide; acrylonitrile; 1,3-butadiene; and ethylene oxide) than combustible cigarette–only, dual combustible cigarette–e-cigarette, or dual combustible cigarette–NRT users. The e-cigarette–only users had significantly lower NNAL levels than all other groups. Combustible cigarette–only, dual combustible cigarette–NRT, and dual combustible cigarette–e-cigarette users had largely similar levels of TSNA and VOC metabolites.
Cross-sectional design with self-selected sample.
Former smokers with long-term e-cigarette–only or NRT-only use may obtain roughly similar levels of nicotine compared with smokers of combustible cigarettes only, but results varied. Long-term NRT-only and e-cigarette–only use, but not dual use of NRTs or e-cigarettes with combustible cigarettes, is associated with substantially reduced levels of measured carcinogens and toxins relative to smoking only combustible cigarettes.
Primary Funding Source:
Cancer Research UK.
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Author, Article, and Disclosure Information
From University College London and King's College, London, United Kingdom; Roswell Park Cancer Institute, Buffalo, New York; and Centers for Disease Control and Prevention, Atlanta, Georgia.
Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health and the U.S. Food and Drug Administration.
Acknowledgment: The authors thank Kate Sheals and Victoria Nelson for their help with data collection and the Centers for Disease Control and Prevention reviewers for providing a thorough review of the manuscript.
Financial Support: This work was supported by Cancer Research UK (grant C27061/A16929, with additional funding from grants C1417/A14135 and C36048/A11654). Dr. Brown's post is funded by a fellowship from the Society for the Study of Addiction, and Cancer Research UK also provides support (grants C1417/A7972 and C44576/A19501). Drs. McNeill and West are part of the UK Centre for Tobacco and Alcohol Studies, which is a UK Clinical Research Collaboration Public Health Research Centre of Excellence. Funding from the Medical Research Council, British Heart Foundation, Cancer Research UK, Economic and Social Research Council, and the National Institute for Health Research under the auspices of the UK Clinical Research Collaboration is gratefully acknowledged (grant MR/K023195/1). Dr. Goniewicz was supported by the National Institute on Drug Abuse and the National Cancer Institute of the National Institutes of Health (awards R01DA037446 and P30 CA016056, respectively) and by an award from Roswell Park Alliance Foundation.
Disclosures: Dr. Shahab reports grants from Cancer Research UK during the conduct of the study and grants from Pfizer (unrestricted research funding to study smoking cessation) and personal fees from Atlantis Health Care outside of the submitted work. Dr. Goniewicz reports grants from Pfizer (2011 GRAND [Global Research Awards for Nicotine Dependence] recipient) and personal fees from Johnson & Johnson (as a member of the advisory board) outside the submitted work. Dr. Brown reports grants (unrestricted research funding to study smoking cessation) from Pfizer outside the submitted work. Dr. West reports grants, personal fees, and nonfinancial support (that is, research grants, consultancy, travel, and hospitality) from Pfizer, Johnson & Johnson, and GlaxoSmithKline outside the submitted work; in addition, Dr. West's salary is funded by Cancer Research UK and he is an advisor to the UK National Centre for Smoking Cessation and Training. Authors not named here have disclosed no conflicts of interest. Disclosures can also be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M16-1107.
Editors' Disclosures: Christine Laine, MD, MPH, Editor in Chief, reports that she has no financial relationships or interests to disclose. Darren B. Taichman, MD, PhD, Executive Deputy Editor, reports that he has no financial relationships or interests to disclose. Cynthia D. Mulrow, MD, MSc, Senior Deputy Editor, reports that she has no relationships or interests to disclose. Deborah Cotton, MD, MPH, Deputy Editor, reports that she has no financial relationships or interest to disclose. Jaya K. Rao, MD, MHS, Deputy Editor, reports that she has stock holdings/options in Eli Lilly and Pfizer. Sankey V. Williams, MD, Deputy Editor, reports that he has no financial relationships or interests to disclose. Catharine B. Stack, PhD, MS, Deputy Editor for Statistics, reports that she has stock holdings in Pfizer and Johnson & Johnson.
Reproducible Research Statement:Study protocol: Not available. Statistical code and data set: Available from Dr. Shahab (e-mail, lion.
Corresponding Author: Lion Shahab, PhD, Department of Epidemiology and Public Health, University College London, 1-19 Torrington Street, London WC1E 7HB, United Kingdom; e-mail, lion.
Current Author Addresses: Drs. Shahab and West: Department of Epidemiology and Public Health, University College London, 1-19 Torrington Street, London WC1E 7HB, United Kingdom.
Dr. Goniewicz: Department of Health Behavior, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263.
Drs. Blount, Alwis, Feng, and Wang: Tobacco and Volatiles Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, GA 30341.
Dr. Brown: Department of Clinical, Educational and Health Psychology, University College London, 1-19 Torrington Street, London WC1E 7HB, United Kingdom.
Dr. McNeill: Addictions Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 4 Windsor Walk, London SE5 8AF, United Kingdom.
Author Contributions: Conception and design: L. Shahab, M.L. Goniewicz, J. Brown, A. McNeill, R. West.
Analysis and interpretation of the data: L. Shahab, M.L. Goniewicz, B.C. Blount, J. Brown, J. Feng, L. Wang, R. West.
Drafting of the article: L. Shahab, B.C. Blount, A. McNeill, K.U. Alwis, R. West.
Critical revision of the article for important intellectual content: L. Shahab, M.L. Goniewicz, B.C. Blount, J. Brown, A. McNeill, R. West.
Final approval of the article: L. Shahab, M.L. Goniewicz, B.C. Blount, J. Brown, A. McNeill, R. West.
Statistical expertise: L. Shahab.
Obtaining of funding: L. Shahab, B.C. Blount, J. Brown.
Administrative, technical, or logistic support: L. Shahab, M.L. Goniewicz.
Collection and assembly of data: L. Shahab, M.L. Goniewicz, B.C. Blount, J. Feng.
This article was published at Annals.org on 7 February 2017.