title: Smoking and mental health: cross-sectional and cohort studies in an occupational setting in Japan.
abstract: BACKGROUND
  The relationship between smoking and mental health remains unclear.
  
  
  METHODS
  We carried out a cross-sectional study and a cohort study on the possible association of smoking and mental health in 782 workers. Using a questionnaire including the 30-item General Health Questionnaire (GHQ-30) and items related to the smoking state, the association between smoking and mental health was evaluated separately in males and females. The subjects were classified into smokers and nonsmokers, and changes in the GHQ score during a 2-year follow-up period were evaluated. To control potential confounding factors, multiple regression analyses were performed.
  
  
  RESULTS
  The cross-sectional study showed no difference in the GHQ score between smokers and nonsmokers among males but a significantly higher GHQ score for smokers than nonsmokers among females. This difference among females was confirmed to be significant by multiple regression analysis. The 2-year cohort study showed a decrease in the GHQ score in each group and no reduction in the difference in the GHQ score between smokers and nonsmokers among females.
  
  
  CONCLUSIONS
  No difference was observed in mental health between smokers and nonsmokers in males. However, in females, smokers showed poorer mental health than nonsmokers, and this difference remained unchanged even after 2 years.
authors: Department of Hygiene and Preventive Medicine, Okayama University Medical School, 2-5-1 Shikata-cho, Okayama, 700-8558, Japan. yoshmino@med.okayama-u.ac.jp
authors: Y
authors: Y
authors: Mino
authors: J
authors: J
authors: Shigemi
authors: T
authors: T
authors: Otsu
authors: A
authors: A
authors: Ohta
authors: T
authors: T
authors: Tsuda
authors: N
authors: N
authors: Yasuda
authors: A
authors: A
authors: Babazono
authors: E
authors: E
authors: Yamamoto
mesh_terms: D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology*; D008603:Mental Health; D015999:Multivariate Analysis; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology / Q000523:psychology