Evaluating E-Cigarette Nicotine Form, Concentration, and Flavors Among Youth

Plasma nicotine concentration from blood drawn (3mL) 4 times in each session at baseline (0 min), 5 min., 10 min., 35 min.

E-cig puff topography data collection for abuse liability. Number of puffs taken during the 30 minutes of ad libitum (as desired) vaping session.

E-cig puff topography data collection for abuse liability. Average puff duration during the 30 minutes of ad libitum (as desired) vaping session, in seconds.

E-cig puff topography data collection for abuse liability. The total volume of all puffs taken for each participant during the 30 minutes of ad libitum (as desired) vaping session, in ml.

Lung function data will be collect using a handheld spirometry device. Physiological effects of pulmonary function collected from inhaled and exhaled breaths. Measures amount inhaled and how quickly exhaled.

Change from baseline in forced expiratory volume (FEV) Change from baseline in forced vital capacity (FVC)

Physiological effects of pulmonary function collected from inhaled and exhaled breaths. Airway inflammation will be assessed using exhaled nitric oxide via the NIOX VERO.

Background measures. Comprised of 9 items each of which range 0-4 from "never" to "almost always".

The 3 subscales (enjoyment of taste and smell, pleasurable physical sensations, enjoyment of vapor cloud production) are the average of 3 items each; scores range from 0 to 4 with higher scores indicating greater enjoyment.

Assess e-cigarette dependence.

Scores range from 5 to 25 with higher scores indicating a greater level of dependence.

An adapted version of the Drug Effects/Liking Questionnaire will assess the desire and liking of UBMC and all three study products, positive and negative effects (i.e., side effects), and perceived strength and effectiveness. Five visual analog scale items ranging from 0 ('not at all') to 100 ('extremely') assessed wanting to smoke the product again, liking the product, enjoying the product, finding the product pleasurable and satisfying.

The modified Cigarette Evaluation Questionnaire (mCEQ) will assess subjective responses to e-cigarettes (e.g., reward, satisfaction). The 12-item mCEQ includes five subscales: Smoking Satisfaction, Psychological Reward, Aversion, Enjoyment of Respiratory Tract Sensations, and Craving Reduction, with items rated from 1 (not at all) to 7 (extremely likely). Items are averaged to create each of the subscales also ranging from 1 to 7 with higher values indicating greater levels of smoking satisfaction, psychological reward, aversion, enjoyment of respiratory tract sensations, an craving reduction.

Behavioral economic demand Asks participants how much they would be willing to pay (ranging from 0¢ to $1,120) for a puff of their study product. Specifically they will be asked, "Thinking about the study product, how many puffs of e-cigarette would you smoke if they were each at the following prices?". Breakpoint is the first price of zero consumption.

E-cig craving/suppression of craving and withdraw will be measured using the Tiffany-Drobes Questionnaire of Smoking Urges (QSU): Brief Form with a modified version (replacing the word "cigarette" with "e-cigarette"). This is a 10-item measure where participants rate smoking/vaping-related items on a 7-point Likert scale ranging from 1 (strongly disagree) to 7 (strongly agree). Similar to previous studies, we will collapse the items into two previously identified factors (Factor 1: strong desire and intention to smoke/vape; Factor 2: anticipation of relief from withdrawal symptoms). Scores are calculated by summing the items and range from 5 to 35 for each of the factors with higher scores indicating greater craving to smoke/vape.

Endothelial function will be collected through EndoPAT device. Specifically, the natural log of RHI, the reactive hyperemia index, will be recorded.

The RHI (Reactive Hyperemia Index) or LnRHI (natural log of RHI) is the post-to-pre occlusion PAT™ signal ratio in the occluded arm, relative to the same ratio in the control arm, corrected for baseline vascular tone. Values less than 1.67 or higher than 0.51 are considered to be abnormal.