Electronic Nicotine Delivery Systems Use and Nicotine Exposure among Adults Who Use ENDS Alone or wi

Edwards KC, Garcia-Rosales K, Goniewicz ML, Ashley D, Hatsukami D, Wang L, Feng J, Blount BC, Sharma E, Merrill LS, Taylor K, Duffy K, Harvanko A, Del Valle-Pinero A, Christensen CH, Chang CM, van Bemmel D, Rivers DL, Mishina EV, Tolliver EA, Roh EJ, Hammad HT, Kc P, Xu K, Montes de Oca R, Cheng YC, Everard C, Kimmel HL, Blanco C, Compton W, Hyland A.
Electronic Nicotine Delivery Systems Use and Nicotine Exposure among Adults Who Use ENDS Alone or with Cigarettes: The Population Assessment of Tobacco and Health Study 2013-2019
Nicotine Tob Res. 2025 Sep 23;27(10):1750-1759. doi: 10.1093/ntr/ntaf083. PMID: 40253576; PMCID: PMC12453681.

Introduction: Evaluating nicotine exposure (total nicotine equivalents-2; TNE-2) changes over time can provide data on the public health impact of electronic nicotine delivery systems (ENDS). This study describes TNE-2 levels of those who use ENDS with or without cigarettes from 2013-2019, and models how changing ENDS use behavior impacts change in TNE-2.

Aims and methods: Creatinine-corrected TNE-2 was assessed for exclusive ENDS use and dual ENDS and cigarette use from Waves (W) 1-5 of the Population Assessment of Tobacco and Health Study. Exploratory analyses using generalized estimated equations modeled how changing ENDS use (ie, frequency of use, flavor use, device type) between wave pairs (W1-W2, W2-W3, etc.) impacted changes in TNE-2.

Results: For exclusive ENDS use at each wave, TNE-2 levels increased from 10.1 µmol/g at W1 to 18.4 µmol/g at W5, a positive linear trend (p = .03). Among those who exclusively used ENDS at all waves, TNE-2 levels peaked at W3 and then decreased at W5, exhibiting a significant quadratic trend (p = .02). Switching from non-daily to daily use (n = 15) was associated with a greater increase in TNE-2 than continued daily use (n = 304). For dual use, TNE-2 levels remained relatively flat, and there were no significant effects of changing ENDS behavior on TNE-2.

Conclusions: For exclusive ENDS use, TNE-2 levels over time differ when looking within-subjects versus repeated longitudinal assessments, and frequency of use was the only significant predictor of change in TNE-2. TNE-2 from dual-use did not significantly change from 2013-2019 and was not impacted by change in ENDS use behavior.

Implications: Exclusive ENDS use was associated with a positive linear trend in nicotine exposure between 2013 and 2019, which may reflect how newer generations of ENDS are better at delivering nicotine. When limiting analysis to within-subject use at all waves the trend was quadratic, with nicotine exposure peaking at W3 and returning toward W1 levels by W5. This may be related to people trying to titrate their nicotine exposure in response to changes in ENDS characteristics. Dual ENDS and cigarette use had more consistent levels of exposure over time, which could be due to the greater ease of nicotine titration via cigarettes.