Sleep disorders and daytime fatigue are common health problems in middle-ag
ed and elderly populations, and they vary greatly between occupational grou
ps. There is widespread evidence that working hours and job stress may expl
ain these differences. In this study the relationship of job demands and jo
b control to sleep disorders was investigated. The subjects were 3079 middl
e-aged working men. The data were collected with a questionnaire including
scales on sleep quality, job stress and lifestyle. The main effects of job
demands and job control on insomnia, sleep deprivation and daytime fatigue
were highly significant. Some interaction effects of the stressors were als
o noted. Lifestyle factors were not found as significant mediators or confo
unders of the effects. The associations between the stressors and sleep dis
orders were greater in the daytime workers than in the shift workers. The m
ain conclusion is that job stressors have a direct relationship to sleep di
sorders, independent of working hours and lifestyle. Copyright (C) 2000 Joh
n Wiley & Sons, Ltd.