title: Short-term pulmonary effects of using an electronic cigarette: impact on respiratory flow resistance, impedance, and exhaled nitric oxide.
abstract: BACKGROUND
  Debate exists over the scientific evidence for claims that electronic cigarettes (e-cigarettes) have no health-related ramifications. This study aimed to assess whether using an e-cigarette for 5 min has an impact on the pulmonary function tests and fraction of exhaled nitric oxide (Feno) of healthy adult smokers.
  
  
  METHODS
  Thirty healthy smokers (aged 19-56 years, 14 men) participated in this laboratory-based experimental vs control group study. Ab lib use of an e-cigarette for 5 min with the cartridge included (experimental group, n = 30) or removed from the device (control group, n = 10) was assessed.
  
  
  RESULTS
  Using an e-cigarette for 5 min led to an immediate decrease in Feno within the experimental group by 2.14 ppb (P = .005) but not in the control group (P = .859). Total respiratory impedance at 5 Hz in the experimental group was found to also increase by 0.033 kPa/(L/s) (P < .001), and flow respiratory resistance at 5 Hz, 10 Hz, and 20 Hz also statistically increased. Regression analyses controlling for baseline measurements indicated a statistically significant decrease in Feno and an increase in impedance by 0.04 kPa/(L/s) (P = .003), respiratory resistance at 5 Hz by 0.04 kPa/(L/s) (P = .003), at 10 Hz by 0.034 kPa/(L/s) (P = .008), at 20 Hz by 0.043 kPa/(L/s) (P = .007), and overall peripheral airway resistance (β, 0.042 kPa/[L/s]; P = .024), after using an e-cigarette.
  
  
  CONCLUSIONS
  e-Cigarettes assessed in the context of this study were found to have immediate adverse physiologic effects after short-term use that are similar to some of the effects seen with tobacco smoking; however, the long-term health effects of e-cigarette use are unknown but potentially adverse and worthy of further investigation.
authors.affiliation: Center for Global Tobacco Control, Department of Society, Human Development, and Health, Harvard School of Public Health, Boston, MA; Smoking and Lung Cancer Research Center, Hellenic Cancer Society, Athens, Greece. Electronic address: vardavas@hsph.harvard.edu.
authors.forename: Constantine I
authors.initials: CI
authors.lastname: Vardavas
authors.affiliation: Smoking and Lung Cancer Research Center, Hellenic Cancer Society, Athens, Greece; Laboratory of Respiratory Physiology, Department of Medicine, University of Athens, Greece.
authors.forename: Nektarios
authors.initials: N
authors.lastname: Anagnostopoulos
authors.affiliation: Smoking and Lung Cancer Research Center, Hellenic Cancer Society, Athens, Greece; Laboratory of Respiratory Physiology, Department of Medicine, University of Athens, Greece.
authors.forename: Marios
authors.initials: M
authors.lastname: Kougias
authors.affiliation: Smoking and Lung Cancer Research Center, Hellenic Cancer Society, Athens, Greece.
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Evangelopoulou
authors.affiliation: Center for Global Tobacco Control, Department of Society, Human Development, and Health, Harvard School of Public Health, Boston, MA.
authors.forename: Gregory N
authors.initials: GN
authors.lastname: Connolly
authors.affiliation: Center for Global Tobacco Control, Department of Society, Human Development, and Health, Harvard School of Public Health, Boston, MA; Smoking and Lung Cancer Research Center, Hellenic Cancer Society, Athens, Greece; Laboratory of Respiratory Physiology, Department of Medicine, University of Athens, Greece.
authors.forename: Panagiotis K
authors.initials: PK
authors.lastname: Behrakis
mesh_terms: D000328:Adult; D000403:Airway Resistance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D012044:Regression Analysis; D012129:Respiratory Function Tests; D012907:Smoking / Q000009:adverse effects*; D018709:Statistics, Nonparametric; D061485:Tobacco Use Cessation Devices / Q000009:adverse effects*
chemical_list: D009569:Nitric Oxide