Harm reduction associated with dual use of cigarettes and e-cigarettes in Black and Latino smokers: Secondary analyses from a randomized controlled e-cigarette switching trial.

Abstract

INTRODUCTION\nMost adult cigarette smokers who use e-cigarettes are dual cigarette and e-cigarette (CC-EC) users, yet little is known about relative consumption of cigarettes to e-cigarettes and any associated harm reduction.\n\n\nMETHODS\nRate of substitution from cigarettes to e-cigarettes at week 6 and change in biomarkers of exposure and potential harm were examined among dual CC-EC users [64/114 (56%); 35 Black, 29 Latino] in an e-cigarette switching randomized trial.\n\n\nRESULTS\nDual users averaged 79% substitution of cigarettes for e-cigarettes at week 6, resulting in a reduction from baseline of 70.0 ± 54.1 cigarettes per week (p < .001). Total nicotine consumption remained stable (baseline: 1160.5 ± 1042.1 pg/mL of cotinine, week 6: 1312.5 ± 1725.9 pg/mL of cotinine, p = .47), while significant reductions were seen in the potent lung carcinogen 4-(methylnitrosamino)-1-(3-pyridul)-1-butanol (NNAL) (-55.9 ± 88.6\xa0ng/ml, p < .001), carbon monoxide (-6.3 ± 8.6\xa0ppm, p < .001), and self-reported respiratory symptoms (-3.3 ± 8.0, p = .002). No significant changes were found in blood pressure or spirometry. Greater substitution from cigarettes to e-cigarettes was associated with larger reductions in NNAL (r = -.29, p = .02).\n\n\nCONCLUSIONS\nThe predominant dual use pattern was characterized by regular e-cigarette and intermittent cigarette use. Findings demonstrate the short-term harm reduction potential of this dual use pattern in Black and Latino smokers and suggest that the greatest benefit, aside from cessation of both products, is achieved by higher substitution of e-cigarettes for cigarettes. Findings need confirmation in a larger sample with longer follow-up in dual users with greater variability in rate of substitution.