title: Reductions in biomarkers of exposure (BoE) to harmful or potentially harmful constituents (HPHCs) following partial or complete substitution of cigarettes with electronic cigarettes in adult smokers.
abstract: Changes 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.
authors.affiliation: a Fontem Ventures, B.V, Scientific and Regulatory Affairs , Amsterdam , The Netherlands ;
authors.forename: Grant
authors.initials: G
authors.lastname: O'Connell
authors.affiliation: b Celerion Inc, Lincoln , USA ;
authors.forename: Donald W
authors.initials: DW
authors.lastname: Graff
authors.affiliation: c Fontem Ventures, B.V , Greensboro , NC , USA.
authors.forename: Carl D
authors.initials: CD
authors.lastname: D'Ruiz
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis / Q000097:blood / Q000652:urine; D001944:Breath Tests; D066300:Electronic Nicotine Delivery Systems / Q000009:adverse effects*; D005260:Female; D015386:Hazardous Substances / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D006801:Humans; D008297:Male; D015394:Molecular Structure; D009538:Nicotine / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D012907:Smoking / Q000097:blood / Q000652:urine
chemical_list: D015415:Biomarkers; D015386:Hazardous Substances; D009538:Nicotine
keywords: Biomarkers of exposure; cessation; e-cigarettes; exclusive and dual use; harm reduction