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.

This study compares patterns of e-cigarette use and the exposure to the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in African American smokers, randomized to ad lib e-cigarettes containing nicotine vs. no nicotine. We hypothesized that nicotine e-cigarettes would be used more than no-nicotine e-cigarettes, and that this would be associated with reduced use of combustible cigarettes. We hypothesized that nicotine e-cigarettes would result in more substitution for combusted cigarettes than no-nicotine e-cigarettes and result in lower levels of exposure to the tobacco-specific carcinogen NNAL. These results would be relevant for developing exposure reduction strategies for adult African American smokers.

Inclusion Criteria:

1. self-identify as African American or Black;
2. age 18 years or older;
3. smoke at least five cigarettes daily for the past year;
4. not interested in quitting smoking in the next 6 months;
5. Willing to use e-cigarettes;
6. Good physical health (no unstable medical or mental health condition);
7. no contraindications for e-cigarette use.

Exclusion Criteria:

1. Recent unstable or untreated psychiatric diagnosis including substance abuse, as determined by the DSM-IV criteria;
2. use in the past 30 days of tobacco or nicotine products including e-cigarettes, other than regular cigarettes;
3. participation in a smoking cessation program in the past 30 days;
4. pregnant or nursing.

2 participants in each group withdrew from the study and were not included in the baseline characteristic data.

24 weeks

All participants are blinded to intervention group