title: Carboxyhaemoglobin levels, health and lifestyle perceptions in smokers converting from tobacco cigarettes to electronic cigarettes.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease and lung cancer are diseases associated with smoking tobacco cigarettes. Smokers find cessation difficult.
  
  
  OBJECTIVE
  To determine whether smoking the Twisp electronic cigarette (e-cigarette), containing nicotine in a vegetable-based glycerine substance, would reduce carboxyhaemoglobin (COHb) levels in regular cigarette smokers by (i) comparing arterial and venous COHb levels before and after smoking the Twisp e-cigarette for 2 weeks; and (ii) evaluating changes in participants' perception of their health and lifestyle following the use of Twisp e-cigarettes.
  
  
  METHODS
  A single group within-subject design was used where tobacco cigarette smokers converted to Twisp e-cigarettes for 2 weeks. Prior to using the Twisp e-cigarette and after using this device for 2 weeks, arterial COHb, venous COHb and venous cotinine levels were determined. Additionally, the participants were asked to complete a questionnaire outlining their perceptions on health and lifestyle.
  
  
  RESULTS
  Thirteen participants of median age 38 years (range 23 - 46) with a smoking median of 20 cigarettes/day (range 12 - 30) completed the study. COHb levels (%) were significantly reduced after smoking Twisp e-cigarettes for 2 weeks (mean ± standard deviation (SD) arterial COHb before 4.66±1.99 v. after 2.46±1.35; p=0.014 and mean ±SD venous COHb before 4.37±2.1 v. after 2.50±1.23; p=0.018). There was excellent agreement between arterial and venous COHb levels (intraclass correlation coefficient 0.916). A decrease in cotinine levels (p=0.001) and an increase in oxygen saturation (p=0.002) were also observed. The majority of participants perceived improvements in their health and lifestyle parameters.
  
  
  CONCLUSIONS
  Smoking the Twisp e-cigarette may be a healthier and more acceptable alternative to smoking tobacco cigarettes.
authors.affiliation: Lung Function Laboratory, 1 Military Hospital, Pretoria, South Africa. snippie33@gmail.com.
authors.forename: Sandri Rachelle
authors.initials: SR
authors.lastname: van Staden
authors.forename: Marcelle
authors.initials: M
authors.lastname: Groenewald
authors.forename: Rifke
authors.initials: R
authors.lastname: Engelbrecht
authors.forename: Piet Johannes
authors.initials: PJ
authors.lastname: Becker
authors.forename: Lynton Tempest
authors.initials: LT
authors.lastname: Hazelhurst
mesh_terms: D000328:Adult; D002263:Carboxyhemoglobin / Q000378:metabolism*; D003367:Cotinine / Q000097:blood; D055615:Electrical Equipment and Supplies; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000097:blood*; D013019:South Africa; D061485:Tobacco Use Cessation Devices
chemical_list: D002263:Carboxyhemoglobin; D003367:Cotinine