[Investigation of subjective symptoms among visual display terminal users and their affecting factors--analysis using log-linear models].

In order to evaluate factors affecting visual and musculoskeletal symptoms by visual display terminal (VDT) operation, a questionnaire survey was conducted among clerical workers in Chiba university. The results were as follows: 1) Of these workers, 81.9% engaged in VDT operation. For most of the subjective symptoms, the prevalence rates tended to increase with the degree of VDT use. 2) These complaints were combined to give visual and musculoskeletal symptom scores. Both of the scores were higher among females than males, and the musculoskeletal symptom score was significantly higher. No difference was found in regard to age. 3) Analysis using log-linear models was performed to evaluate the effects of sex and age. The results showed that the visual and musculoskeletal symptom scores were significantly higher among the workers operating VDTs for one or more hours per day than among those who did not operate them at all. Analysis of the effects of VDT workloads revealed that VDT use for five or more days per week significantly increased the prevalence rates of both symptoms. Their use for less than four days per week affected neither of the symptoms. With regard to operating time per day or length of VDT use, no differences were found. 4) This investigation suggested that the VDT workloads were not so heavy and that the effects on each symptom were minor among the subjects of the present survey. However, it is important that consideration be given to ensure that the workloads for workers who operate VDTs every day not be too heavy.