title: A comparison of oxidative stress in smokers and non-smokers: an in vivo human quantitative study of n-3 lipid peroxidation.
abstract: BACKGROUND
  Cigarette smoking is believed to cause oxidative stress by several mechanisms, including direct damage by radical species and the inflammatory response induced by smoking, and would therefore be expected to cause increased lipid peroxidation. The aim was to carry out the first study of the relationship of smoking in humans to the level of n-3 lipid peroxidation indexed by the level of ethane in exhaled breath.
  
  
  METHODS
  Samples of alveolar air were obtained from 11 smokers and 18 non-smokers. The air samples were analyzed for ethane using mass spectrometry.
  
  
  RESULTS
  The two groups of subjects were matched with respect to age and gender. The mean cumulative smoking status of the smokers was 11.8 (standard error 2.5) pack-years. The mean level of ethane in the alveolar breath of the group of smokers (2.53 (0.55) ppb) was not significantly different from that of the group of non-smokers (2.59 (0.29) ppb; p = 0.92). With all 29 subjects included, the Spearman rank correlation coefficient between ethane levels and cumulative smoking status was -0.11 (p = 0.58), while an analysis including only the smokers yielded a corresponding correlation coefficient of 0.11 (p = 0.75).
  
  
  CONCLUSIONS
  Our results show no evidence that cigarette smoking is related to increased n-3 lipid peroxidation as measured by expired ethane.
authors.affiliation: MRI Unit, MRC Clinical Sciences Centre, Imaging Sciences Department, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK. basant.puri@csc.mrc.ac.uk
authors.forename: Basant K
authors.initials: BK
authors.lastname: Puri
authors.forename: Ian H
authors.initials: IH
authors.lastname: Treasaden
authors.forename: Massimo
authors.initials: M
authors.lastname: Cocchi
authors.forename: Sofia
authors.initials: S
authors.lastname: Tsaluchidu
authors.forename: Lucio
authors.initials: L
authors.lastname: Tonello
authors.forename: Brian M
authors.initials: BM
authors.lastname: Ross
mesh_terms: D000328:Adult; D001944:Breath Tests; D004980:Ethane / Q000032:analysis*; D045853:Exhalation; D015525:Fatty Acids, Omega-3 / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D018384:Oxidative Stress; D012016:Reference Values; D012907:Smoking / Q000378:metabolism*
chemical_list: D015525:Fatty Acids, Omega-3; D004980:Ethane