Compensatory Behavior of E-cig Users in Response to Reduced Nicotine E-liquids

This project will investigate whether and how e-cig users compensate puff topography, lung inhalation, and cumulative consumption in response to reduced nicotine eliquid. The project is conducted in the natural environment to objectively measure if users adapt their behavior to maintain their desired level of nicotine.

The project employs a novel behavior-based exposure model that leverages the unique abilities of the investigative team to objectively capture real world behavior. The study employs a novel wPUM™ monitor to record puffing topography and a sensorized shirt to record respiratory parameters for every vaping session.

This study is conducted in the natural environment over 17 days. We will recruit N=80 current established adult ecig users, currently using eliquids with nicotine strengths greater than or equal to 5%, with no intention to quit e-cig use, and no use of combustible or other tobacco products. Participants will be randomized by age, gender, usual brand nicotine strength, and nicotine dependence score into a control arm (non-switching) and a test arm (switching). All participants will be baselined with 5% Juul ecigs and Juul pods containing Virginia Tobacco at 5% nicotine strength. The test arm will be switched to a 3% Juul pods containing Virginia Tobacco at 3% nicotine strength eliquid, while the control arm will continue to use 5% nicotine strength.

Participants will use the RIT wPUM monitor with a Juul ecig and a wearable sensorized garment to record their e-cigarette use topography and inhalation behavior ad-lib in their natural environment at the baseline and intervention conditions for one day each. Biosamples for nicotine exposure in saliva, NNAL in urine and CO will be collected, along with questionnaires to assess product use, compliance, and psychosocial outcomes such as craving, withdrawal and positive/negative emotional state.

Aim 1. Quantify changes in Total Particulate Matter (TPM) exposure among e-cig users adapting to low nicotine eliquids through compensatory changes in puffing, inhalation, and consumption behavior.

TPM exposure will be quantified in the natural environment by recording the topography (puff flow rate, duration, volume) of every puff taken along with respiratory behavior (inhalation/exhalation volume and time and breath hold). This novel outcome measure of exposure is used as a proxy to indicate the impact of behavior on increasing harm potential. We will test hypothesis (H1) that upon changing to a lower nicotine eliquid, users will adapt their behavior (i.e. increase breath hold, adjust puff flow rate, etc.), and in doing so will increase their TPM exposure.

Aim 2. Quantify changes in salivary among e-cig users adapting to low nicotine eliquids.

Salivary cotinine will be measured as a proxy to indicate efficacy of compensatory behavior. A Generalized Linear Mixed-Effects Model (GLME) analysis will be used to investigate how the ability of users to compensate for low nicotine e-liquids is affected by the presence of random effects including sex, age, nicotine dependence score, usual brand nicotine strength, and subjective effects including craving, withdrawal symptoms, and positive/negative emotional state. We will test the hypothesis (H2) that users are able to maintain desired nicotine levels while using a lower nicotine eliquid.

Relationship to Tobacco Regulation: Knowledge gained will support development of effective tobacco product regulations by informing three research questions of regulatory interest: (a) Will limiting the eliquid nicotine concentration reduce harm at the population level? (b) Is there evidence of compensatory behavior exhibited by e-cig users in response to reduced nicotine concentration, and (c) Can we conduct meaningful behavior-based e-cig use risk assessment at the individual level?