A new study published in Addiction (by the society for the Study of Addiction) has found significant harm reduction when switching from smoking to vaping or dual use. Following a systematic review, this secondary analysis incorporated nine studies from Greece, Italy, Poland, the United Kingdom and the United States. It features 1,299 adult participants who smoked combustible cigarettes (CC), switched completely from smoking CC to electronic cigarettes (EC), or who switched to using both CC and EC (dual users).

In a secondary analysis, researchers work with previously collected existing data (secondary data) to perform a new study. This allows researchers to work with large data sets, as they can work with data from multiple studies. A systematic review uses all the existing research and also secondary research (research on research). A high-quality systematic review is one of the most reliable sources of evidence to guide clinical practice, as it delivers a meticulous summary of the available primary research in response to a research question.

Measurements for the study were conducted using carbon monoxide (CO) and other biomarkers. Biomarkers (biological markers) are biological molecules found in body fluids or tissues that signal a normal or abnormal process or a condition or disease. Measuring biomarkers enabled the researchers to indicate how biomarkers of harm change based on participants’ smoking/vaping behaviour.

The study found exhaled CO (eCO) to be lower in participants who switched to EC completely than those who smoke CC or are dual users. eCO was also significantly lower in dual users than in CC only participants. 13 biomarkers were measured to compare EC versus CC – of these, 12 were lower in the EC groups. 25 biomarkers were measured when comparing EC to CC and dual use – of these, the results were lower for EC groups for 12 measures and for dual use groups for 5 measures.

This secondary analysis confirms that exclusive EC use is associated with lower levels of biomarkers of harm than the exclusive use of CC or dual use. This supports the broad scientific consensus that the greatest health improvements come from ceasing the use of CC completely, and that (although not completely without risk) EC is a reduced-risk alternative that offers harm reduction benefits. An analysis such as this study not only informs debates concerning the potential harms and benefits of dual use but also illustrates the changes a smoker might expect if they switched completely to ECs or dual use.

Access www.tobaccoharmreduction.net to learn more about tobacco harm reduction.