Smoking and mental health: Cross-sectional and cohort studies in an occupational setting in Japan

Background The relationship between smoking and mental health remains uncle ar. Methods. We carried out a cross-sectional study and a cohort study on the p ossible association of smoking and mental health in 782 workers. Using a qu estionnaire including the 30-item General Health Questionnaire (GHQ-30) and items related to the smoking state, the association between smoking and me ntal health was evaluated separately in males and females. The subjects wer e classified into smokers and nonsmokers, and changes in the GHQ score duri ng a 2-year followup period were evaluated. To control potential confoundin g factors, multiple regression analyses were performed. Results. The cross-sectional study showed mo difference in the GHQ score be tween smokers and nonsmokers among males but a significantly higher GHQ sco re for smokers than nonsmokers among females, This difference among females was confirmed to be significant by multiple regression analysis. The S-yea r cohort study showed a decrease in the GHQ score in each group and no redu ction in the difference in the GHQ score between smokers and nonsmokers amo ng females. Conclusions. No difference was observed in mental health between smokers an d nonsmokers in males. However, in females, smokers showed poorer mental he alth than nonsmokers, and this difference remained unchanged even after 2 y ears. (C) 2001 American Health Foundation and Academic Press.