a Randomized Clinical Trial Examining the Effects of Instructions for Electronic Cigarette Use on Smoking-Related Behaviors and Biomarkers of Exposure.

Introduction:
This text summarizes the results of a randomized clinical trial examining the effects of instructions for electronic cigarette use on smoking-related behaviors and biomarkers of exposure. The study aimed to determine the extent to which instructions and monetary incentives to completely switch to e-cigarettes among smokers can reduce smoking rate and biomarkers of exposure compared to instructions for ad libitum use of e-cigarettes and complete substitution with nicotine replacement therapies (NRTs).

Key Points:

* The study randomized 264 adult daily smokers to one of four groups: ad libitum use of e-cigarettes (aD-E), complete substitution of cigarettes with e-cigarettes (CS-E), complete substitution of cigarettes with nicotine gum or lozenge (CS-NRT), or continued smoking of usual brand cigarettes (UB).
* Participants in the CS-E and CS-NRT groups showed lower rates of smoking and lower exposure to carbon monoxide, tobacco carcinogens, and other toxicants than smokers in the aD-E group.
* Significantly higher 7-day point prevalence smoke-free rates were observed for CS-E versus CS-NRT.
* No significant differences were observed between CS-E versus CS-NRT or between aD-E versus UB for most biomarkers.
* The primary e-cigarette product was Vuse Solo with four flavor choices. Nicotine gum or lozenge was provided in the 4 mg dose. Smokers assigned to the UB or aD-E cigarette condition purchased their own cigarettes.
* Biomarker outcomes included urinary total nicotine equivalents, exhaled CO, tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, and volatiles organic compounds (VOCs).
* The study found that smokers instructed and incentivized to completely switch to e-cigarettes resulted in lower smoking rates and greater reductions in exposures to harmful chemicals than smokers instructed to use the product ad libitum.

Main Message:
The main message of this study is that approaches to maximize complete substitution with e-cigarettes are an important area for future research. Smokers instructed to completely substitute e-cigarettes for cigarettes displayed significantly lower levels of smoking and biomarkers of exposure to carcinogens and toxicants, compared to smokers instructed to use e-cigarettes ad libitum and similar levels as smokers instructed to completely substitute with nicotine replacement therapies. Furthermore, a higher rate of complete switching was achieved with e-cigarettes versus nicotine replacement therapies. Therefore, regulatory measures should consider promoting complete substitution with e-cigarettes as a harm reduction strategy for smokers.

hatsukami DK, Meier E, Lindgren BR, et al. a Randomized Clinical Trial Examining the Effects of Instructions for Electronic Cigarette Use on Smoking-Related Behaviors and Biomarkers of Exposure. Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco. 2020;22(9):1524-1532. doi:10.1093/ntr/ntz233