Rising vape pod popularity disrupted declining use of electronic nicotine delivery systems among young adults in Texas, USA from 2014 to 2019

Abstract

Aims: To examine the longitudinal trajectory of young Texan (US) adults' electronic nicotine delivery systems (ENDS) use from 2014 to 2019, and to determine if there are changes in the trajectory among younger and older young adults post-2017, when vape pods surged in popularity in the United States.

Design: Nine-wave longitudinal study, with 6 months between each of the first eight waves and 1 year between the last two waves. Discontinuous, or piecewise, growth curve models were used to test the hypotheses that (a) the overall current/past 30-day ENDS use trajectory would decline from 2014 to spring 2017 but then increase from fall 2017 to 2019, and (b) the increasing trajectory from 2017 to 2019 would occur only for younger participants, but not older participants. All models included socio-demographic covariates of sex, race/ethnicity, type of college attended at baseline (2- or 4-year) and time-varying age.

Setting and participants: A total of 5218 students (aged 18-25 years at baseline; 63.7% female) from 24 colleges in the five counties surrounding Austin, Dallas/Fort Worth, Houston and San Antonio, Texas, USA.

Measurements: Participants completed on-line surveys regarding past 30-day ENDS use at all nine waves.

Findings: Current ENDS use significantly declined from 2014 to spring 2017 [odds ratio (OR) = 0.63, 95% confidence interval (CI) = 0.59-0.68], and then significantly increased from autumn 2017 to 2019 (OR = 1.14, 95% CI = 1.01-1.29). Further examination indicated the increase in current ENDS use from autumn 2017 to 2019 occurred only for younger [-1 standard deviation (SD) below the mean age, 22.6 years old], but not older (+1 SD above the mean age, 26.2 years old), participants.

Conclusion: The surge in the popularity of vape pods in the United States in late 2017 may have contributed to increasing use of electronic nicotine delivery systems among younger young adults (below 22.6 years) from late 2017 to 2019.

Keywords: ENDS trajectories; e-cigarette; growth models; juul; longitudinal models; young adult tobacco use.