• Grant O'Connell, Donald W Graff, and Carl D D'Ruiz.
• a Fontem Ventures, B.V, Scientific and Regulatory Affairs , Amsterdam , The Netherlands ;
• Toxicol. Mech. Methods. 2016 Jul 1; 26 (6): 443-54.

AbstractChanges in fifteen urine, blood and exhaled breath BoEs of HPHCs representing classes of compounds reported by FDA to be significant contributors to smoking-associated disease risks were measured in 105 clinical-confined subjects following randomization and a five-day forced-switch from usual brand conventional combustible cigarettes to: (i) exclusive commercial e-cigarette use; (ii) dual-use of commercial e-cigarettes and the subject's usual cigarette brand; or (iii) discontinued use of all tobacco or nicotine products. Levels of urinary biomarkers in subjects that completely substituted their usual cigarette with e-cigarettes were significantly lower (29-95%) after 5 days. Percent reductions in eight of nine urinary BoEs were indistinguishable to smokers who had quit smoking, except for nicotine equivalents, which declined by 25-40%. Dual users who halved self-reported daily cigarette consumption with e-cigarettes exhibited reductions (7-38%) in eight of nine urinary biomarkers, but had increase (1-20%) in nicotine equivalents. Reductions were broadly proportional to the reduced numbers of cigarettes smoked. Dual user urinary nicotine equivalents were slightly higher, but not statistically significant. After 5 days, blood nicotine biomarker levels were lower in the cessation (75-96%) and exclusive use groups (11-83%); with dual users experiencing no significant reductions. All subjects experienced significant decreases in exhaled CO. Decreases in the cessation and exclusive groups ranged from 88-89% and 27-32% in dual users. Exhaled NO increased in the cessation and exclusive groups (46-63% respectively), whereas the dual users experienced minimal changes. Overall, smokers who completely or partially substituted conventional cigarettes with e-cigarettes over five days, experienced reductions in HPHCs.

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