Heterogeneity in the measurement and reporting of outcomes in studies of electronic cigarette use in adolescents, a systematic analysis of observational studies

Abstract

Uncertainty about whether electronic cigarettes act as a gateway to tobacco addiction for adolescents has led to global debate on this topic. We examined consistency between cross-sectional studies of conventional and electronic cigarette use among adolescents in terms of the measurement, analysis, and reporting of parameters. A systematic analysis was performed of cross-sectional studies of conventional and electronic cigarette use in adolescents, to identify measured and reported parameters. Studies were identified by searching the SCOPUS database in August 2015. Two reviewers independently selected relevant studies from the search and extracted data. 60 abstracts were identified; 31 papers were eligible for review (23 unique studies). Measured and reported parameters were collated, including the prevalence of cigarette and/ or e-cigarette use, and the definitions of terms. For “ever” or “current” use of electronic or conventional cigarettes, there were 17 unique permutations of measured parameters across the 23 studies, and 33 different data points were presented. Of 16/23 studies in which authors collected information on “dual current use”, this prevalence was reported in 11/16. “Dual use” was calculated and reported in six different ways across all studies. Many studies assumed that “e-cigarette” use was synonymous with nicotine use. There are substantial differences in the measurement and reporting of parameters in these studies, which are consequently at risk of reporting bias. A core outcome set should be developed in this area, using structured consensus techniques.