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

INTRODUCTION
The objective of this clinical trial was to compare the effects of e-cigarettes with and without nicotine on patterns of combustible cigarette use and biomarkers of exposure to tobacco toxicants among African American smokers.


METHODS
African American smokers (n=234) were enrolled in a 12-week, single blind, randomized controlled trial and assigned to ad lib use of nicotine e-cigarettes with or without menthol (2.4% nicotine [equivalent to combustible cigarettes], n=118), or no-nicotine e-cigarettes (n=116) for 6 weeks. Surveys were administered at baseline, 2, 6, and 12 weeks, and urinary biomarkers 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and total nicotine equivalents (TNE) were assessed at baseline and 6 weeks.


RESULTS
Participants smoked an average of 11.4 cigarettes per day (CPD) and 88% used menthol cigarettes at baseline. At Week 6, the nicotine group reported using e-cigarettes 9.1 times per day compared to 11.4 times in the no-nicotine group (p=0.42). Combustible cigarette smoking decreased 3.0 CPD in the nicotine group compared to 2.7 CPD in the no-nicotine group (p=0.74). Neither TNE nor NNAL changed significantly between baseline and Week 6. There were no differences in nicotine withdrawal symptoms between treatment groups. Smoking reduction persisted in both groups at Week 12.


CONCLUSIONS
Contrary to our hypotheses, nicotine e-cigarettes did not significantly reduce the use of combustible cigarettes compared to no-nicotine e-cigarettes in this cohort of African American smokers. Findings suggest e-cigarettes modestly are associated with decreased use of combustible cigarettes among non-treatment seeking smokers, regardless of nicotine content, but without a reduction in tobacco toxicants.


IMPLICATIONS
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.