Impact of e-cigarette and cigarette prices on youth and young adult e-cigarette and cigarette behaviour: evidence from a national longitudinal cohort.

INTRODUCTION:Understanding the impact of prices for tobacco and nicotine products is critical for creating policies to prevent use among young people. This study examines the impact of electronic cigarette (e-cigarette) and cigarette prices on current e-cigarette and cigarette use among youth and young adults. METHODS:Data were from a national probability-based sample aged 15-21 collected in 2014 and followed every 6 months for 2.5 years through 2016. We conducted separate conditional likelihood logistic regression models with past 30-day e-cigarette use and past 30-day cigarette use outcomes on the sample of individuals who participated in at least two survey waves (n=11 578) with linked Nielsen market-level price data for rechargeable e-cigarettes and cigarettes. Models controlled for time-varying variables at the individual and state policy levels, and fixed effects at the individual, wave and market levels. RESULTS:Higher cigarette prices were associated with increased past 30-day e-cigarette use, indicating e-cigarettes may serve as a substitute for cigarettes. We did not find a statistically significant relationship between rechargeable e-cigarette prices and past 30-day e-cigarette use; neither did we find a significant relationship between rechargeable e-cigarette prices and past 30-day cigarette smoking. CONCLUSION:This is the first study to examine e-cigarette and cigarette prices on e-cigarette and cigarette behaviour longitudinally among young people. Findings suggest the need for better measuring the costs associated with e-cigarette use among this population, as well as a careful assessment of price and tax policies that takes into account cross-product impact to sufficiently discourage e-cigarette and cigarette use among young people.