title: Respiratory effects of lowering tar and nicotine levels of cigarettes smoked by young male middle tar smokers. II. Results of a randomised controlled trial.
abstract: OBJECTIVE
  The aim was to investigate the effect on respiratory health of male middle tar smokers changing the tar and nicotine levels of the cigarettes they smoke for a six month period.
  
  
  METHODS
  This was a randomised controlled trial. Middle tar smokers were randomly allocated to smoke one of three different types of cigarette (low tar, middle nicotine; middle tar, middle nicotine; and low tar, low nicotine) in place of their usual cigarette for a six month period. Main outcome measures were assessment of respiratory health by documenting respiratory symptoms and peak expiratory flow rates, and of nicotine inhalation by measuring the urinary excretion of nicotine metabolites.
  
  
  METHODS
  21 local authority districts of England.
  
  
  METHODS
  Participants were male middle tar smokers aged 18-44 years.
  
  
  RESULTS
  Changes in the measures of respiratory health showed little difference over the trial period between the three cigarette groups. Analyses of the urinary nicotine metabolites showed that smokers allocated to each of the three study cigarettes adjusted their smoking so that throughout the trial their nicotine inhalation differed little from their pretrial intakes when they were smoking their own cigarettes. As a result of the altered patterns of smoking to compensate for the reduced nicotine yields of the three study cigarettes, the tar intake of those allocated to smoke the middle tar, middle nicotine cigarettes remained essentially unchanged, while those allocated to smoke the low tar, low nicotine and low tar, middle nicotine cigarettes had calculated reductions in tar intakes of about 14% and 18%, respectively.
  
  
  CONCLUSIONS
  Due to the phenomenon of compensation, tar intake can only be reduced substantially by using a cigarette with a markedly lower tar/nicotine ratio. Nevertheless reductions of up to about 18% in tar intake failed to result in any detectable effect on respiratory symptoms or peak expiratory flow rates over a six month period.
authors.affiliation: Department of Public Health Medicine, United Medical School, Guy's Hospital, London, United Kingdom.
authors.forename: C H
authors.initials: CH
authors.lastname: Withey
authors.forename: A O
authors.initials: AO
authors.lastname: Papacosta
authors.forename: A V
authors.initials: AV
authors.lastname: Swan
authors.forename: B A
authors.initials: BA
authors.lastname: Fitzsimons
authors.forename: G A
authors.initials: GA
authors.lastname: Ellard
authors.forename: P G
authors.initials: PG
authors.lastname: Burney
authors.forename: J R
authors.initials: JR
authors.lastname: Colley
authors.forename: W W
authors.initials: WW
authors.lastname: Holland
mesh_terms: D000293:Adolescent; D000328:Adult; D004739:England / Q000453:epidemiology; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008297:Male; D009538:Nicotine / Q000737:chemistry* / Q000652:urine; D010349:Patient Compliance; D010366:Peak Expiratory Flow Rate; D010947:Plants, Toxic; D015995:Prevalence; D012140:Respiratory Tract Diseases / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology / Q000652:urine; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology / Q000503:physiopathology / Q000652:urine; D013638:Tars / Q000737:chemistry*; D014026:Nicotiana / Q000737:chemistry*
chemical_list: D013638:Tars; D009538:Nicotine