title: Cigarettes vs. e-cigarettes: Passive exposure at home measured by means of airborne marker and biomarkers.
abstract: BACKGROUND
  There is scarce evidence about passive exposure to the vapour released or exhaled from electronic cigarettes (e-cigarettes) under real conditions. The aim of this study is to characterise passive exposure to nicotine from e-cigarettes' vapour and conventional cigarettes' smoke at home among non-smokers under real-use conditions.
  
  
  METHODS
  We conducted an observational study with 54 non-smoker volunteers from different homes: 25 living at home with conventional smokers, 5 living with nicotine e-cigarette users, and 24 from control homes (not using conventional cigarettes neither e-cigarettes). We measured airborne nicotine at home and biomarkers (cotinine in saliva and urine). We calculated geometric mean (GM) and geometric standard deviations (GSD). We also performed ANOVA and Student's t tests for the log-transformed data. We used Bonferroni-corrected t-tests to control the family error rate for multiple comparisons at 5%.
  
  
  RESULTS
  The GMs of airborne nicotine were 0.74 μg/m(3) (GSD=4.05) in the smokers' homes, 0.13 μg/m(3) (GSD=2.4) in the e-cigarettes users' homes, and 0.02 μg/m(3) (GSD=3.51) in the control homes. The GMs of salivary cotinine were 0.38 ng/ml (GSD=2.34) in the smokers' homes, 0.19 ng/ml (GSD=2.17) in the e-cigarettes users' homes, and 0.07 ng/ml (GSD=1.79) in the control homes. Salivary cotinine concentrations of the non-smokers exposed to e-cigarette's vapour at home (all exposed ≥ 2 h/day) were statistically significant different that those found in non-smokers exposed to second-hand smoke ≥ 2 h/day and in non-smokers from control homes.
  
  
  CONCLUSIONS
  The airborne markers were statistically higher in conventional cigarette homes than in e-cigarettes homes (5.7 times higher). However, concentrations of both biomarkers among non-smokers exposed to conventional cigarettes and e-cigarettes' vapour were statistically similar (only 2 and 1.4 times higher, respectively). The levels of airborne nicotine and cotinine concentrations in the homes with e-cigarette users were higher than control homes (differences statistically significant). Our results show that non-smokers passively exposed to e-cigarettes absorb nicotine.
authors.affiliation: Tobacco Control Unit, Cancer Prevention and Control Program, Institut Català d׳Oncologia, L'Hospitalet de Llobregat, Barcelona, Spain; Catalan Network of Smoke-free Hospitals, L׳Hospitalet de Llobregat, Barcelona, Spain; Cancer Prevention and Control Group, Institut d׳Investigació Biomèdica de Bellvitge - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Addictions Unit, Institute of Neurosciences, Hospital Clínic de Barcelona - IDIBAPS, Barcelona, Spain; Department of Clinical Sciences, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Montse
authors.initials: M
authors.lastname: Ballbè
authors.affiliation: Tobacco Control Unit, Cancer Prevention and Control Program, Institut Català d׳Oncologia, L'Hospitalet de Llobregat, Barcelona, Spain; Cancer Prevention and Control Group, Institut d׳Investigació Biomèdica de Bellvitge - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Biostatistics Unit, Department of Basic Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Barcelona, Spain. Electronic address: jmmartinez@iconcologia.net.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Martínez-Sánchez
authors.affiliation: Tobacco Control Unit, Cancer Prevention and Control Program, Institut Català d׳Oncologia, L'Hospitalet de Llobregat, Barcelona, Spain; Cancer Prevention and Control Group, Institut d׳Investigació Biomèdica de Bellvitge - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Department of Clinical Sciences, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Xisca
authors.initials: X
authors.lastname: Sureda
authors.affiliation: Tobacco Control Unit, Cancer Prevention and Control Program, Institut Català d׳Oncologia, L'Hospitalet de Llobregat, Barcelona, Spain; Cancer Prevention and Control Group, Institut d׳Investigació Biomèdica de Bellvitge - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Department of Clinical Sciences, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Marcela
authors.initials: M
authors.lastname: Fu
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Pérez-Ortuño
authors.affiliation: IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain; Department of Experimental and Life Sciences, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Pascual
authors.affiliation: Health Plan Directorate, Ministry of Health, Generalitat de Catalunya, Spain; Department of Public Health, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Esteve
authors.initials: E
authors.lastname: Saltó
authors.affiliation: Tobacco Control Unit, Cancer Prevention and Control Program, Institut Català d׳Oncologia, L'Hospitalet de Llobregat, Barcelona, Spain; Catalan Network of Smoke-free Hospitals, L׳Hospitalet de Llobregat, Barcelona, Spain; Cancer Prevention and Control Group, Institut d׳Investigació Biomèdica de Bellvitge - IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Department of Clinical Sciences, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Esteve
authors.initials: E
authors.lastname: Fernández
mesh_terms: D015415:Biomarkers / Q000032:analysis*; D003367:Cotinine / Q000032:analysis / Q000652:urine; D066300:Electronic Nicotine Delivery Systems / Q000009:adverse effects*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009538:Nicotine / Q000032:analysis; D012463:Saliva / Q000737:chemistry; D013030:Spain; D062789:Tobacco Products / Q000009:adverse effects*; D014028:Tobacco Smoke Pollution / Q000032:analysis*
chemical_list: D015415:Biomarkers; D014028:Tobacco Smoke Pollution; D009538:Nicotine; D003367:Cotinine
keywords: Biological markers; Electronic cigarette; Electronic nicotine delivery system (ENDS); Tobacco smoke pollution