The right amount of e-cigarette nicotine may cut smoking

"This study shows that when smokers interested in reduction are provided with an e-cigarette with cigarette-like nicotine delivery, they are more likely to achieve significant decreases in tobacco-related toxicants, such as lower exhaled carbon monoxide levels," says Jonathan Foulds. (Credit: Getty Images)

E-cigarettes that deliver a cigarette-like amount of nicotine are associated with reduced smoking and reduced exposure to a major cancer-causing chemical in tobacco, a new study shows.

The findings, which hold true even with concurrent smoking, provide new and important information for smokers who may be trying to use e-cigarettes as a means to cut down on their smoking habit and lower their exposure to harmful toxicants.

“We found that e-cigarettes that delivered a similar amount of nicotine as traditional, combustible cigarettes, helped reduce smoking and exposure to a harmful carcinogen,” says Jonathan Foulds, a researcher at the Penn State Cancer Institute and professor of public health sciences and psychiatry and behavioral health.

“This study shows that when smokers interested in reduction are provided with an e-cigarette with cigarette-like nicotine delivery, they are more likely to achieve significant decreases in tobacco-related toxicants, such as lower exhaled carbon monoxide levels.”

The researchers conducted a randomized controlled trial of 520 participants who smoked more than nine cigarettes a day, were not currently using an e-cigarette device, and were interested in reducing smoking but not quitting.

Over 24 weeks, participants used an e-cigarette device filled with either 0, 8, or 36 milligrams per milliliter of liquid nicotine or a plastic tube (shaped like a cigarette) that delivered no nicotine or aerosol. Researchers chose the e-cigarette conditions to reflect a range of nicotine delivery: either none, low (8 mg/ml) or cigarette-like (36 mg/ml). Researchers also provided participants with smoking reduction instructions.

At weeks 0, 4, 12, and 24, the researchers sampled participants’ urine, testing for the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, also known as NNAL. They found that participants using e-cigarettes filled with the cigarette-like level of liquid nicotine had significantly lower levels of NNAL at week 24 compared to baseline and compared to levels observed in the non-e-cigarette control condition.

According to Foulds, the findings represent an important addition to the scientific literature because they suggest that when e-cigarettes deliver nicotine effectively, smokers have greater success in reducing their smoking and tobacco-related toxicant exposure.

Lead author Caroline Cobb, an associate professor of psychology at Virginia Commonwealth University, says the study is important for two reasons.

“First, many e-cigarettes have poor nicotine-delivery profiles, and our results suggest that those products may be less effective in helping smokers change their behavior and associated toxicant exposure,” Cobb says.

“Second, previous randomized controlled trials examining if e-cigarettes help smokers change their smoking behavior and toxicant exposure have used e-cigarettes with low or unknown nicotine delivery profiles,” Cobb says.

“Our study highlights the importance of characterizing the e-cigarette nicotine delivery profile before conducting a randomized controlled trial. This work also has other important strengths over previous studies including the sample size, length of intervention, multiple toxicant exposure measures, and control conditions.”

The question of whether an e-cigarette’s nicotine delivery profile is predictive of its ability to reduce harm and promote behavior change among smokers remains highly relevant to policymakers, public health advocates, health care providers, and smoking populations. That knowledge will lead to better designed studies of the potential harms and benefits of e-cigarettes and ultimately inform tobacco regulatory policy, Cobb says.

The study contributes to the ongoing question of what role e-cigarettes play in changing smoking behavior, Foulds says. Additionally, the study’s findings support limited safety concerns for the use of the specific e-cigarette and liquid combinations over the short term, even in the context of concurrent cigarette smoking.

However, Cobb says, very little is known about the effects of e-cigarettes over the course of years, as opposed to the study’s 24-week period.

Additional coauthors of the study, which appears in The Lancet–Respiratory Medicine, are from the University of Wisconsin-Milwaukee, the University of Auckland in New Zealand, Virginia Commonwealth University, and Penn State.

The National Institutes of Health and the US Food and Drug Administration supported the work. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding groups.

Foulds has done paid consulting for pharmaceutical companies involved in manufacturing smoking-cessation medications (e.g., Pfizer, GlaxoSmithKline, Johnson & Johnson); and has acted as a deposed and compensated expert witness on behalf of plaintiffs suing cigarette manufacturers. None of the study authors have accepted funding from tobacco or electronic cigarette manufacturers.

Source: Penn State