E-cigarette use to reduce cigarette smoking may not increase nicotine dependence, study suggests

Smoking is a leading cause of death in the U.S., and despite interest in quitting and the availability of FDA-approved cessation methods, smokers still struggle to quit. Some public health experts have proposed e-cigarettes as a “reduced harm” alternative to cigarettes for those not interested or able to quit, citing reports like one from the National Academies of Sciences, Engineering and Medicine, which found that substitution of e-cigarettes for combustible cigarettes reduced users’ exposures to carcinogens and other harmful toxicants.

Jessica Yingst, assistant professor of public health sciences and Penn State Cancer Institute researcher, and colleagues at the Penn State Center for Research on Tobacco and Health study e-cigarettes and whether they can help nicotine users stop smoking or reduce their exposure to harmful toxicants found in cigarettes. Their latest study investigated a common question — whether initiation of electronic cigarette use to reduce cigarette smoking could potentially increase nicotine dependence.

“Research on this topic is conflicted because, in prior studies, participants used their own devices with unknown nicotine delivery profiles,” Yingst said. “Our study used devices with known nicotine delivery profiles, which allowed us to effectively compare how the varying levels of nicotine in a device might affect user nicotine dependence and ability to reduce cigarette consumption.”

The researchers enrolled 520 participants interested in reducing their cigarette intake but with no plans or interest to quit smoking and instructed them to reduce their cigarette consumption over the six-month study period. Participants randomly received an e-cigarette that delivered 36, 8 or 0 mg/mL of nicotine, or a cigarette substitute that contained no tobacco, as an aid in their efforts to reduce their cigarette consumption.

Participants self-reported their cigarette and e-cigarette dependence at one, three and six months using validated measures of dependence, including a Penn State-developed questionnaire that ranges from 0 (not at all dependent) to 20 (highly dependent). Urine samples were also collected throughout the study to measure cotinine, a biomarker for nicotine exposure.

At six months, all participants in the e-cigarette groups reported significant, decreased cigarette consumption, with those in the 36 mg/mL group smoking the least number of cigarettes per day. Those in the e-cigarette groups reported significantly lower dependence on the Penn State Cigarette Dependence Index than those in the cigarette substitute group.

Participants also reported their e-cigarette dependence using the Penn State E-Cigarette Dependence Index. E-cigarette dependence did not significantly change throughout the study, with the exception of participants in the 36 mg/mL group who saw significant, increased dependence over the course of the study, yet still much lower when compared with cigarette dependence. Urine cotinine levels remained consistent across all groups for the duration of the study, suggesting that there was no increase in overall exposure to nicotine during the study. The results were published in the journal Nicotine and Tobacco Research.

“Our results suggest that using e-cigarettes or a cigarette substitute to reduce cigarette consumption can result in a reduction of self-reported cigarette use and dependence,” said Yingst, who directs the College of Medicine’s Doctor of Public Health Program. “Importantly, use of the high concentration e-cigarette did not increase overall nicotine dependence, and was associated with a greater reduction in cigarette smoking compared to the cigarette substitute.”

While it has been hypothesized that the use of e-cigarettes could increase overall nicotine dependence, the research team said their study found that initiating e-cigarette use to reduce cigarette consumption resulted in reduced cigarette dependence and low e-cigarette dependence. In the future, they will evaluate the health effects of completely switching from cigarettes to e-cigarettes.

Xi Wang and Jonathan Foulds of Penn State College of Medicine; Alexa Lopez of the University of Wisconsin-Milwaukee; Alison Breland, Andrew Barnes, Megan Underwood and Melanie Crabtree of Virginia Commonwealth University; Eric Soule of East Carolina University College of Health and Human Performance; and Joanna Cohen of John Hopkins Bloomberg School of Public Health also contributed to this research. Foulds has done paid consulting for pharmaceutical companies involved in manufacturing smoking-cessation medications (e.g., Pfizer, GlaxoSmithKline, Johnson and Johnson); and has acted as a deposed and compensated expert witness on behalf of plaintiffs suing cigarette manufacturers. Other author disclosures can be read in the published manuscript.

This research was supported by the National Institute on Drug Abuse of the National Institutes of Health and the Center for Tobacco Products of the U.S. Food and Drug Administration (grant numbers P50DA036105 and U54DA036105). Data collection was supported by Penn State Clinical and Translational Science Institute (grant number UL1TR002014) and the C. Kenneth and Dianne Wright Center for Clinical and Translational Research at Virginia Commonwealth University (grant number UL1TR002649) through the National Center for Advancing Translational Sciences of the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the sponsors.

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Materials provided by Penn State. Original written by Zach Sweger. Note: Content may be edited for style and length.