This is an observational, crossover study that will be examine use behaviors, chemical exposures, and biological effects of SREC compared to TC use in subjects confined to a research ward setting.
Daily cigarette smokers who are familiar with e-cigarette (EC) use will be instructed to use only NIDA Standardized Research Electronic Cigarettes (SREC) and tobacco cigarettes (TC) while enrolled on the study. Our overall goals are two-fold: (1) to compare nicotine and toxicant exposure and pharmacological effects of SREC used alone vs tobacco cigarettes alone (TC), or dual use; and (2) using SREC alone, TC alone, or ad libitum SREC use combined with 50% reduction in usual TC use as a model for dual use, to examine the extent to which nicotine and toxicant exposure and biomarkers of potential harm compare among the 3 groups. The former would inform the effects of total switching, the latter would inform the potential harm reducing effects of smoking fewer TC while using EC.