Biomarkers of Exposure among “Dual Users” of Tobacco Cigarettes and Electronic Cigarettes in Canada.

Introduction:
This text summarizes the results of a study examining biomarkers of exposure among dual users of tobacco cigarettes and electronic cigarettes in Canada. The study aimed to investigate how biomarkers of exposure change under different conditions of product use.

Key Points:

* The study used a nonblinded within-subjects crossover experiment design with adult daily dual users in Ontario, Canada.
* Participants completed three consecutive 7-day periods in which the use of tobacco cigarettes and e-cigarettes was experimentally manipulated, resulting in four study conditions: Dual use, Tobacco cigarette use, E-cigarette use, and No product use.
* Compared to dual use, cotinine remained stable when participants exclusively smoked, but significantly decreased when they exclusively vaped.
* Levels of biomarkers of exposure to toxicants, including carbon monoxide, 1-hydroxypyrene, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, were significantly lower when participants exclusively vaped than when they engaged in dual use.
* Similar findings were observed among participants abstaining from both products as compared to dual use.
* In contrast, levels of biomarkers of exposure increased when participants exclusively smoked as compared to dual use.
* The study suggests that although dual use may reduce exposure to tobacco smoke constituents to some extent, abstaining from smoking is the most effective way to reduce such exposure.

Main Message:
The main message of the study is that while dual use of tobacco cigarettes and electronic cigarettes may reduce exposure to some toxicants, it does not eliminate exposure. abstaining from smoking is the most effective way to reduce exposure to harmful tobacco smoke constituents. Public health authorities should communicate the relative risk of e-cigarettes and tobacco cigarettes to the general public, focusing on the fact that e-cigarettes are not harmless but are likely to be less harmful than tobacco cigarettes. however, using e-cigarettes while smoking may not necessarily reduce health risks, and consumers should stop smoking completely to maximize potential health benefits.

Czoli CD, Fong GT, Goniewicz ML, hammond D. Biomarkers of Exposure among “Dual Users” of Tobacco Cigarettes and Electronic Cigarettes in Canada. Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco. 2019;21(9):1259-1266. doi:10.1093/ntr/nty174