A very interesting study in the Journal of Health Economics has been published. I don't have access to the full article, but the abstract is posted below:
From: http://www.sciencedirect.com/science/article/pii/S0167629615001150
From: http://www.sciencedirect.com/science/article/pii/S0167629615001150
Understanding electronic cigarettes’ effect on tobacco smoking is a central economic and policy issue. This paper examines the causal impact of e-cigarette access on conventional cigarette use by adolescents. Regression analyses consider how state bans on e-cigarette sales to minors influence smoking rates among 12 to 17 year olds. Such bans yield a statistically significant 0.9 percentage point increase in recent smoking in this age group, relative to states without such bans. Results are robust to multiple specifications as well as several falsification and placebo checks. This effect is both consistent with e-cigarette access reducing smoking among minors, and large: banning electronic cigarette sales to minors counteracts 70 percent of the downward pre-trend in teen cigarette smoking in the states that implemented such bans.