Association between duration of daily visual display terminal work and insomnia among local government clerks in Japan

BACKGROUND: Visual display terminal (VDT) work has become very common among office workers in developed countries; however, studies investigating the association between the duration of daily VDT work and insomnia are limited. METHODS: The aim of this study was to clarify the association between the duration of daily VDT work and sleep disturbances. We investigated 2,417 clerks (men, 2,030; women, 387) at local government offices. Sleep disturbances were evaluated using the Athens Insomnia Scale (AIS). RESULTS: VDT work of 6 hr or more per day was significantly associated with insomnia (odds ratio = 1.62, 95% confidence interval: 1.16-2.27) and, in particular, caused problems with "total sleep duration" and "sleepiness during the day" among sleep-related symptoms, even after adjusting for possible confounding factors. CONCLUSIONS: Our study suggested that VDT work of 6 hr or longer per day was related to insomnia.