Awareness of Changes in E-cigarette Regulations and Behavior Before and After Implementation: A Longitudinal Survey of Smokers, Ex-smokers, and Vapers in the United Kingdom.

INTRODUCTION: In line with the European Union's Tobacco Products Directive (TPD), new regulations for electronic cigarettes implemented in the United Kingdom between May 2016 and May 2017 included limiting refills to 10 mL, tank and cartridge sizes to 2 mL, and nicotine concentrations to 20 mg/mL. AIMS: To investigate the (1) awareness of new regulations, (2) product use before and after implementation, and (3) association between use of compliant products and subsequent smoking. METHODS: A UK online longitudinal survey of smokers, ex-smokers, and vapers was conducted between May and June 2016 (wave 4) and September 2017 (wave 5).The following methods were used: (1) to assess awareness of changes, proportions were calculated by smoking and vaping status (n = 1606). (2) Comparison of refill volume, tank and cartridge volumes, nicotine concentration at waves 4 and 5 (n = 199-388) was conducted. (3) Association was studied between number of TPD-compliant products used at wave 4 and smoking at wave 5, adjusted for wave 4 vaping status, age, gender, income, urges to smoke, and device type (n = 480). RESULTS: Awareness of regulations was highest for refill volume (10.1%; 37.4% among exclusive vapers) and nicotine concentration (9.5%; 27.3%). Higher proportions used TPD-compliant refill volumes (60.0%-73.7%, χ2(1) = 10.9, p = .001) and nicotine concentrations (89.2%-93.9%, χ2(1) = 7.41, p = .007) in wave 5 than wave 4, with little change for tank or cartridge volumes (77.1-75.5%, χ2(1) = 0.38, p = .540). The likelihood of smoking was similar for those using no or one TPD-compliant products as it was for those using two (OR = 1.10, 95% CI = 0.47-2.59) or three (OR = 1.56, 95% CI = 0.69-3.55). CONCLUSION: Several months after full implementation, awareness of new regulations was low and most vapers used TPD-compliant products. Use of compliant products was not associated with subsequent smoking. IMPLICATIONS: Using a longitudinal survey at the beginning and a few months after the end of the transition period for implementation of new regulation on electronic cigarettes, this is the first study to assess awareness of regulation and use of compliant products. After full implementation, awareness of changes was low overall (smokers, ex-smokers, and vapers combined) although higher among those who vaped. Nevertheless, most vapers (74%-94%) used products that were compliant with the new regulations and the use of products compliant with incoming regulations did not predict whether they were smoking cigarettes after implementation.