[Sleep disorders in shift workers and life-style related disease].

With Japanese social change toward a 24-hour society, a substantial proportion (ca. 27%) of workers is engaged in shift work schedules. It is known that shift workers may occasionally show a complaint of insomnia and/or excessive sleepiness. Thus, circadian rhythm sleep disorder, shift work type(shift work disorder), seems to be prevalent in our society. In shift work disorder, there is a complaint of insomnia or excessive sleepiness that is temporally associated with a recurring work schedule that overlaps the usual time of sleep. Complication may include gastrointestinal symptoms and life-style disease. The present paper overviews evidence on the relationship between shift work disorder and life-style related disease.