An Examination of Objective and Self-Report Measures of Ad Libitum Electronic Cigarette Use: Identifying Patterns of Puffing Behavior and Evaluating Self-Report Items

Abstract

Introduction: There has been little research objectively examining use-patterns among individuals who use electronic cigarettes (e-cigarettes). The primary aim of this study was to identify patterns of e-cigarette use and categorize distinct use-groups by analyzing patterns of puff topography variables over time. The secondary aim was to identify the extent to which self-report questions about use accurately assess e-cigarette use-behavior.

Aims and methods: Fifty-seven adult e-cigarette-only users completed a 4-hour ad libitum puffing session. Self-reports of use were collected both before and after this session.

Results: Three distinct use-groups emerged from exploratory and confirmatory cluster analyses. The first was labeled the "Graze" use-group (29.8% of participants), in which the majority of puffs were unclustered (ie, puffs were greater than 60 seconds apart) with a small minority in short clusters (2-5 puffs). The second was labeled the "Clumped" use group (12.3%), in which the majority of puffs were within clusters (short, medium [6-10 puffs], and/or long [>10 puffs]) and a small minority of puffs were unclustered. The third was labeled the "Hybrid" use-group (57.9%), in which most puffs were either within short clusters or were unclustered. Significant differences emerged between observed and self-reported use-behaviors with a general tendency for participants to overreport use. Furthermore, commonly utilized assessments demonstrated limited accuracy in capturing use behaviors observed in this sample.

Conclusions: This research addressed several limitations previously identified in the e-cigarette literature and collected novel data that provided substantial information about e-cigarette puff topography and its relationship with self-report measures and use-type categorization.

Implications: This is the first study to identify and distinguish three empirically based e-cigarette use-groups. These use-groups, as well as the specific topography data discussed, can provide a foundation for future research assessing the impact of use across different use types. Furthermore, as participants tended to overreport use and assessments did not capture use accurately, this study can serve as a foundation for future work developing more appropriate assessments for use in research studies as well as clinical practice.