PROJECT SUMMARY/ABSTRACT
Electronic nicotine delivery systems (ENDS), particularly e-cigarettes, are increasingly prevalent, with
their use matching or surpassing conventional cigarettes in certain age groups. Unlike combustible
cigarettes, ENDS allow on-demand access to single puffs. Despite the central importance of accurate
characterization of ENDS puff behavior in the natural environment, current assessment approaches are
quite limited. To overcome critical barriers to progress in the field, we propose to evaluate and deploy an
inexpensive instrument that can accurately, objectively, and non-obtrusively track real-time puff behavior
across a wide variety of ENDS products without interrupting the natural behavior of the user. The Flexible
Robust Instrumentation of ENDS (FRIENDS) monitor employs a miniature non-contact electromagnetic
sensor that detects the current flow from the battery through the heater coil, allowing detection of puffs
and puff duration regardless of ENDS generation and/or physical form (e.g., cig-alikes, pens, tanks, and
pods systems). We propose recruiting 240 daily ENDS users, sampled for variety of ENDS devices and
user characteristics. As new ENDS devices are encountered, they will be bench-tested to determine the
best location for FRIENDS attachment, and we will measure the relationship between puff duration and
volume. These results will be added to an open-source FRIENDS library. Each participant will vape ad lib
with their FRIENDS-enabled ENDS during a video-taped lab visit and for 7 days in their natural
environment. Biochemical measures of exposure and a range of self-report data will also be collected. The
study will address several critical questions, including: To what extent does self-report reflect accurately
capture variability (across people and days) in objective real-world vaping frequency, and how much does
objective data from the lab visit improve prediction? To what extent do objective puff measures from
FRIENDS outperform self-report measures in predicting nicotine exposure? Finally, what are the
objective classes of ENDS use behavior (e.g., predominantly “bingers” [the focus of standard self-report]
vs. predominantly “grazers” [a pattern missing from self-report but evident preliminary objective
monitoring studies])? How common is each class? Is the ability of self-report to predict real-world vaping
frequency and nicotine exposure particularly poor for grazers compared to bingers? The proposed study
will provide novel and much-needed information about the nature of ENDS use behavior and has the
potential to markedly influence future work. Moreover, the project will curate an extensive, open-source
FRIENDS library, providing everything needed to produce and use the FRIENDS monitor with 125+
ENDS. Thus, we will make available to the field an inexpensive and accurate method for assessing puff
quantity, duration, and patterning in a wide range of ENDS studies.
