Cardiovascular Health Effects and Synthetic Cooling Agents in E-cigarettes Labeled as "Clear" Marketed in Massachusetts After the Tobacco Product Flavoring Ban

IntroductionMassachusetts (MA) enacted statewide regulation on all flavored tobacco products in June 2020. Thereafter, electronic cigarettes (e-cigarettes) labeled clear emerged on the market. We aimed to combine cardiovascular health effects with chemical analysis of clear e-cigarettes. MethodsWe measured acute changes in blood pressure and heart rate following a 10-minute structured use of participants own e-cigarette, comparing clear e-cigarette users with other flavored e-cigarette users and non-users. Chemical characterization and quantification of relevant flavorings and cooling agents (WS-3, WS-23) of 19 clear-labeled disposable e-cigarette liquids was carried out by GC/MS. ResultsAfter the ban, participants that used clear labeled e-cigarettes increased from 0% to 21%. Increase in diastolic blood pressure and heart rate was significantly greater in clear e-cigarettes users (n=22) compared to both non-clear flavored e-cigarette users (n=114) and non-users (n=72). We saw similar results in heart rate when comparing Juul e-cigarette and clear users; Juul was used as a reference as synthetic coolants WS-3 or WS-23 were not detected in these. All (19/19) clear e-liquids were found to contain synthetic cooling agents WS-23 and/or WS-3, menthol (18/19), as well as other flavorings (12/19). DiscussionThe detected presence of menthol alongside other flavorings in tested clear products is a direct violation of the MA flavored tobacco product regulation, warranting stricter monitoring for new products and constituents. clear e-cigarette use led to greater hemodynamic effects compared to other flavored e-cigarettes and Juul, which raises questions about the effect of cooling agents on users.