Low control at work and the risk of suicide in Japanese men: a prospective cohort study.
BACKGROUND
Although adverse psychosocial job characteristics are suspected predictors of suicide death, prospective studies based on established stress instruments are limited.


METHODS
In a multicenter community-based Japanese cohort study, we prospectively investigated the association between psychosocial job characteristics and the risk of death from suicide among male workers. Baseline examination was conducted from 1992 to 1995 to determine the socioeconomic, behavioural and biological variables in addition to the psychosocial job characteristics of 3,125 male workers aged 65 and under and free from major illness. Low job control and high job demands were measured as adverse psychosocial job characteristics according to a job demand-control model questionnaire. Suicide deaths were identified using the Cause-of-Death Register.


RESULTS
During the 9-year follow-up, 14 suicides were identified. The suicide death rate was 48.1 per 100,000 person years. Multivariate analysis revealed a more than fourfold increase in the risk of suicide among men with low control at work (relative risk: 4.10; 95% confidence interval: 1.31-12.83) compared with counterpart men after adjustment for age, marital status, educational attainment, occupation, smoking status, alcohol consumption, total cholesterol level, and study area. Job demands were not associated with risk of death from suicide.


CONCLUSIONS
By using a job demand-control model questionnaire, low control at work was revealed as a predictor of suicide death among Japanese male workers. The finding implies that job redesign aimed at increased worker control could be a worthwhile strategy in preventing, or at least reducing, the risk of suicide death.
Tsutsumi
Akizumi
A
Occupational Training Center, University of Occupational and Environmental Health, Kitakyushu, Japan. tsutsumi@med.uoeh-u.ac.jp
Kayaba
Kazunori
K
Ojima
Toshiyuki
T
Ishikawa
Shizukiyo
S
Kawakami
Norito
N
D000328:Adult; D044466:Asian People / Q000523:psychology*; D002423:Cause of Death; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D007389:Internal-External Control; D007564:Japan; D007588:Job Satisfaction; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D013405:Suicide / Q000523:psychology* / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires