VDT-related musculoskeletal symptoms: interactions between work posture and psychosocial work factors

Video display terminal (VDT) operators (n = 150) in the editorial department of a large metropolitan newspaper participated in a study of day-to-day musculoskeletal symptoms. Work posture related to the VDT workstation and psychosocial work factors were also investigated for their contributions to the severity of upper body pain, numbness, and stiffness using a representative subsample (n = 70). Self-report measures included Karasek's Job Content Instrument and the author-designed Work Interpersonal Relationships Inventory. Independent observations of work posture were performed using techniques similar to those reported by Sauter et al. [1991]. Pain during the last week was reported by 59% (n = 88) of the respondents, and 28% (n = 42) were categorized by symptom criteria potentially to have musculoskeletal disorders. More hours per day of VDT use and less decision latitude on the job were significant risk factors for potential musculoskeletal CTDs. Head rotation and relative keyboard height were significantly related to more severe pain and stiffness in the shoulders, neck, and upper back. Lower levels of co-worker support were associated with more severe hand and arm numbness. For both the region of the shoulders, neck, and upper back and the hand and arm region, however, the contributions of relative keyboard and seat back heights to symptom severity were modified by psychological workload, decision latitude, and employee relationship with the supervisor. Alternative explanations for these findings are discussed.