have e-cigarettes renormalised or displaced youth smoking? Results of a segmented regression analysis of repeated cross sectional survey data in England, Scotland and Wales.

Introduction:
This text is a summary of a study examining the relationship between e-cigarette use and smoking behaviors and attitudes among young people in the UK. The study aims to understand whether the proliferation of e-cigarettes during a period of limited regulation led to changes in smoking trajectories and attitudes among young people.

Key Points:

* The study used a large, nationally representative sample of school-age children from England, Scotland, and Wales, covering a long time period (17 years).
* The study examined smoking attitudes, contributing to understanding underlying theoretical mechanisms of renormalization.
* The study found little evidence of renormalization of smoking during the period of growing but largely unregulated use of e-cigarettes in the UK.
* The rate of decline for ever smoking prevalence did not slow, and while decreases for regular smoking slowed, this was specific to groups where the level of decline before 2010 was greatest.
* Slowing declines were also found for cannabis and alcohol use, suggesting change in trend was not unique to tobacco use, but reflected wider changes in youth substance use trajectories.
* Positive perceptions of smoking attitudes declined at a faster rate following the proliferation of e-cigarettes, suggesting attitudes towards smoking hardened rather than softening.
* The study is unique in that it is the first to test the renormalization hypothesis by examining changes in trends for youth attitudes toward smoking.

Main Message:
The study provides little evidence to support the hypothesis that e-cigarettes renormalized youth smoking during a period of growing but largely unregulated use in the UK. Instead, the study suggests that the decline in the perceived acceptability of smoking behavior accelerated during this period. These findings have important implications for policy on e-cigarette regulation, suggesting that policy should not be justified on the sole basis of renormalization concerns. additionally, the study highlights the need to consider whether youth e-cigarette use does become a potential problem in isolation from its links to tobacco.

hallingberg B, Maynard OM, Bauld L, et al. have e-cigarettes renormalised or displaced youth smoking? Results of a segmented regression analysis of repeated cross sectional survey data in England, Scotland and Wales. Tobacco control. 2020;29(2):207-216. doi:10.1136/tobaccocontrol-2018-054584