Targeted smoking cessation for dual users of combustible and electronic cigarettes: a randomised controlled trial

Abstract

Background: Although many smokers use electronic cigarettes (e-cigarettes) to quit smoking, most continue to smoke while vaping. This dual use might delay cessation and increase toxicant exposure. We aimed to test the efficacy of a self-help intervention designed to help dual users to quit smoking.

Methods: In this three-arm randomised controlled trial we recruited individuals in the USA using Facebook and multimedia advertisements. Included participants were 18 years or older, smoked at least weekly in the preceding year, and vaped at least weekly in the preceding month. We used computer generated randomisation with balanced-permuted blocks (block size 10, with 2-4-4 ratio) to allocate participants to assessment only (ASSESS group), generic smoking cessation self-help booklets (GENERIC group), or booklets targeting dual users (eTARGET group). Individuals in the generic or targeted intervention groups received monthly cessation materials for 18 months, with assessments every 3 months for 24 months. The main outcome was self-reported 7-day point-prevalence smoking abstinence at each assessment point. All randomly allocated participants were included in primary analyses using generalised estimating equations for each of 20 datasets created by multiple imputation. Analysis of the χ2s produced an F test. The trial is registered with ClinicalTrials.gov, NCT02416011, and is now closed.

Findings: Between July 12, 2016, and June 30, 2017, we randomly assigned 2896 dual users (575 to assessment, 1154 to generic intervention, and 1167 to targeted self-help). 7-day point-prevalence smoking abstinence increased from 14% at 3 months to 42% at 24 months (F7,541·7=67·1, p<0·0001) in the overall sample. Targeted self-help resulted in higher smoking abstinence than did assessment alone throughout the treatment period (F1,973·8=10·20, p=0·0014 [α=0·017]). The generic intervention group had abstinence rates between those of the assessment and targeted groups, but did not significantly differ from either when adjusted for multiple comparisons (GENERIC vs eTARGET F1,1102·5=1·79, p=0·18 [α=0·05]; GENERIC vs ASSESS F1,676·7=4·29, p=0·039 [α=0·025]). Differences between study groups attenuated after the interventions ended.

Interpretation: A targeted self-help intervention with high potential for dissemination could be efficacious in promoting smoking cessation among dual users of combustible cigarettes and e-cigarettes.

Funding: National Institute on Drug Abuse, National Cancer Institute.

Conflict of interest statement

Declaration of interests THB has received research support from the US National Institutes of Health (NIH), the American Cancer Society, the Florida Department of Health, and Pfizer; has collaborated on funded research with Voxiva, Optum, and the University of East Anglia (Norwich, UK); spent a sabbatical period at the Trimbos Institute and Utrecht University (Utrecht, Netherlands); is on the advisory board of, and holds restricted stock in, Hava Health, which is developing a pharmaceutical grade electronic nicotine delivery system for smoking cessation; participated in a Best Brains Exchange for Health Canada, providing advice on e-cigarette policy; and consulted for the Australian Government Solicitor regarding plain tobacco packaging. UM has received research support from the NIH and the Galician Plan of Research, Innovation, and Growth (Spain); and has received funding from the Barrie Foundation to receive predoctoral training at the University of Newcastle (Callaghan, NSW, Australia). VNS has received research support from the NIH and the Florida Department of Health. SKS has received research support from the NIH, the American Cancer Society, the Florida Department of Health, and Pfizer. DJD has received research support from the NIH, the American Cancer Society, and the Florida Department of Health; and has provided paid expert testimony in litigation against tobacco companies. MMB has received funding from the NIH, the Florida Department of Health, the US Department of Veterans Affairs, the US Centers for Disease Control and Prevention, the National Science Foundation, and the US Department of Housing & Urban Development; and has received research support from Gilead Sciences, Florida Blue Foundation, Bristol Myers Squibb Foundation, Merck Foundation, Maine Cancer Foundation, and Pfizer. PTH has received research support from the NIH, US Food and Drug Administration (FDA), and Virginia Foundation for Healthy Youth. TE conducts research supported by the National Institute on Drug Abuse of the NIH and the Center for Tobacco Products of the FDA; is a paid consultant in litigation against the tobacco industry and the electronic cigarette industry; is named on one patent for a device that measures the puffing behaviour of electronic cigarette users and on another patent for a smartphone app that determines electronic cigarette device and liquid characteristics; owns shares in a variety of mutual funds, the exact stock makeup of which he has no control, and owns shares in three publicly traded companies, none of which are in any way related to the tobacco industry, the electronic cigarette industry, or any other aspect of this work; and has served as a special government employee of the US Government in the context of his service on the FDA's Tobacco Products Scientific Advisory Committee and the Department of Health and Human Services Secretary's Advisory Committee on Human Research Protection. CRB has received research support from the New Zealand Ministry of Health, the Health Research Council of New Zealand, CureKids Foundation, Heart Foundation, Health Promotion Agency, and Auckland Council and Sanitarium; collaborates on funded research with Newcastle University (Australia) through a grant from the Australian National Health and Medical Research Council, with Zhejiang University (Hangzhou, China) and Kunming University (Yunnan, China) on an Education New Zealand Tripartite grant, and with the University of Malaya (Kuala Lumpur, Malaysia) on a University of Malaya Grand Challenges grant; received funding from Pfizer Australasia for a survey of the impact of COVID-19 on health workers in low-income and middle-income countries and from Johnson & Johnson Japan for consultancy on smoking cessation medication; and was a consultant to Moffit Cancer Center on this study through an NIH grant. The employees of Moffitt Cancer Center—UM, VNS, SKS, DJD, LRM, KOB, MMB, and THB—are eligible for sharing of any revenue that might be generated by products developed during their employment, including the intervention used in this study. LRM and KOB declare no additional competing interests.

Copyright © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.

Figures

Figure 1:

Trial profile

Figure 2:. Percentage of smokers abstinent by study group for each assessment

Percentage of abstinence averaged across 20 multiple imputed datasets. GENERIC and eTARGET interventions began just after baseline and ended at 18 months.

Figure 3:. Percentage of smokers abstinent for eTARGET and ASSESS for low and higher cigarette dependence

Percentage of abstinence averaged across 20 multiple imputed datasets. eTARGET intervention began just after baseline and ended at 18 months. The low cigarette dependence group (n=409) had Fagerström Test for Nicotine Dependence scores of 1 or lower at baseline, whereas the higher cigarette dependence group (n=1333) had scores of 2 or higher.