A randomized trial of nicotine vs. no-nicotine e-cigarettes among African American smokers: Changes in smoking and tobacco biomarkers.

Although e-cigarettes have potential to reduce harm if substituted for combusted cigarettes (or if they promoted cessation) because of lower levels of tobacco toxicants, this study suggests ad lib use of e-cigarettes among African American smokers, with or without nicotine, results in modest smoking reduction but does not change toxicant exposure in a cohort where smoking cessation or reduction is not the goal. These data suggest that testing future harm reduction interventions using e-cigarettes should include more specific behavioral change coaching, including substituting for or completely stopping combusted cigarettes.