Biomarkers of Electronic Nicotine Delivery Systems (ENDS) use.

Introduction:
This text provides an overview of biomarkers of exposure in electronic nicotine delivery system (ENDS) users to aid in the assessment of the health consequences of using ENDS. It discusses the challenges in identifying novel biomarkers specific to ENDS use and the limitations of current biomarkers. The text also recommends combining several biomarkers to differentiate tobacco product user groups in population-based studies and monitor ENDS compliance in randomized controlled trials.

Key Points:

* Biomarkers of exposure are used to characterize tobacco users’ exposure to harmful and potentially harmful constituents (hPhC), including nicotine, TSNas, Pahs, VOCs, and toxic metals.
* Biomarkers can play an essential role in characterizing the potential health risks of ENDS by demonstrating internal exposure to toxic chemicals present and emitted from specific products.
* Identifying biomarkers specific to ENDS remains challenging because most chemicals identified in ENDS liquids and emissions are ubiquitous in other tobacco products and have familiar dietary and environmental sources.
* Levels of most toxicant biomarkers measured in biological samples collected from ENDS users are statistically the same as in samples from non-users, except for a small number of biomarkers of exposure to VOCs and TSNas.
* Several cross-sectional studies have shown that exclusive ENDS users showed significantly lower levels of toxicant exposure biomarkers while exposed to nicotine than cigarette smokers.
* Studies have shown that concurrent users of ENDS and combustible cigarettes (‘dual users’) are not reducing overall exposure to harmful toxicants compared to exclusive cigarette smokers.
* Biomarkers specific to ENDS have yet to be developed due to the lack of specificity of ENDS biomarkers to ENDS use.

Main Message:
The text highlights the challenges in identifying biomarkers specific to ENDS use due to the ubiquity of most chemicals identified in ENDS liquids and emissions in other tobacco products and consumer products. It recommends combining several biomarkers to differentiate tobacco product user groups in population-based studies and monitor ENDS compliance in randomized controlled trials. The text also emphasizes that while exclusive ENDS users showed significantly lower levels of toxicant exposure biomarkers than cigarette smokers, dual users are not reducing overall exposure to harmful toxicants compared to exclusive cigarette smokers. Therefore, it is crucial to continue research on biomarkers specific to ENDS use to better understand the health consequences of using ENDS.

Goniewicz ML. Biomarkers of Electronic Nicotine Delivery Systems (ENDS) use. addiction neuroscience. 2023;6. doi:10.1016/j.addicn.2023.100077