A new study led by researchers at Virginia Commonwealth University and Penn State College of Medicine in Hershey, Pennsylvania, has found that e-cigarettes that deliver a similar amount of nicotine as cigarettes are associated with reduced smoking and reduced exposure to the major tobacco-related pulmonary carcinogen, NNAL, even with concurrent smoking.
The researchers conducted a randomised 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 did not deliver nicotine or aerosol.
The participants were also provided with smoking reduction instructions.
Over the study period, researchers conducted multiple tests and found that participants who used e-cigarettes filled with liquid nicotine had significantly lower levels of NNAL at week 24.
These findings represent an important addition to current scientific literature as it suggests that when e-cigarettes deliver nicotine effectively, smokers have greater success in reducing smoking and tobacco-related toxicant exposure.
Lead author, Caroline O. Cobb, Ph.D., an associate professor in the VCU Department of Psychology in the College of Humanities and Sciences said, "We found that e-cigarettes with nicotine delivery like a combustible cigarette were effective in helping reduce smoking and exposure to a tobacco-related carcinogen.
"But, it doesn't just happen by accident. It requires the smoker to be actively trying to reduce their smoking by replacing it with e-cigarette use."
Jonathan Foulds, professor of public health sciences at Penn State (one of the two study sites), commented, "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 study contributes to the ongoing question of what role e-cigarettes play in changing smoking behaviour.
"The question of whether an e-cigarette's nicotine delivery profile is predictive of its ability to reduce harm and promote behaviour change among smokers remains highly relevant to policymakers, public health advocates, healthcare 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 added.