title: Trends in socio-economic differentials in cigarette smoking behaviour between 1990 and 1998: a large prospective study in Korean men.
abstract: OBJECTIVE
  To investigate the magnitude and time trends in socio-economic differentials in cigarette smoking behaviour.
  
  
  METHODS
  A prospective observational study of male civil servants followed-up for 8 years.
  
  
  METHODS
  All civil service offices in Korea.
  
  
  METHODS
  A total of 322,991 male civil servants aged 30-49 years on whom information on monthly salary was available and who had reported cigarette smoking behaviour between 1990 and 1998.
  
  
  RESULTS
  Smoking prevalence was 60.1% in 1990 and was inversely associated with salary level. The difference in smoking prevalence between the highest and the lowest salary groups gradually widened from 13.0% in 1990 to 16.1% in 1998. The relative index of inequality (RII) as a measure of socio-economic inequality in smoking behaviour was 1.91 [95% confidence interval (CI) 1.86-1.97] in 1990 and increased between 1990 and 1998. The RII for smoking cessation was 0.60 in 1990 (95% CI 0.58-0.62) and gradually decreased as time lapsed.
  
  
  CONCLUSIONS
  An increasing trend in socio-economic inequality in smoking behaviour was observed in this study.
authors.affiliation: Department of Family Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: H J
authors.initials: HJ
authors.lastname: Cho
authors.forename: Y M
authors.initials: YM
authors.lastname: Song
authors.forename: G Davey
authors.initials: GD
authors.lastname: Smith
authors.forename: S
authors.initials: S
authors.lastname: Ebrahim
mesh_terms: D000328:Adult; D006077:Government Agencies; D015438:Health Behavior; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012309:Risk-Taking; D012907:Smoking / Q000453:epidemiology*; D012959:Socioeconomic Factors; D013997:Time Factors