PREVALENCE OF AND RISK FACTORS FOR UPPER EXTREMITY MUSCULOSKELETAL SYMPTOMS AND DISORDERS AMONG COMPUTER USERS: A CROSS-SECTIONAL STUDY WITH SPECIAL EMPHASIS ON CARPAL TUNNEL SYNDROME

Abstract

Background: A recent change in the Belgian law lead to the obligation of evaluating the musculoskeletal system among employees using visual display terminal (VDT) during the routine annual visit. We conducted a cross-sectional study to determine prevalence of and risk factors for musculoskeletal symptoms (MSS) and disorders (MSD) in general, and carpal tunnel syndrome (CTS) in particular.

Methods: During the routine annual visit all VDT employees of different kinds of companies and occupations were asked about upper extremity MSS by their occupational physician. Participants who met the criteria for MSS within the last month were physically examined in search of a MSD in general, and CTS in particular. Prevalences were calculated, and key risk factors for MSS and CTS were determined using logistic regression analyses.

Results: The total prevalence of any upper extremity MSS among 1087 VDT-employees was 31.3%. Neck symptoms (21.6%) were the most frequently reported, followed by shoulder (21.6%), elbow/forearms (4.1%), hands/wrists (7.3%), and finger (5.2%) symptoms. The prevalence of CTS depended on the diagnostic criteria used: 1.8% for symptom-specific CTS (typical anatomical distribution of numbness and paresthesias), 1.2% for examination-confirmed CTS (at least one positive provocative test, Tinel’s nerve percussion test or Phalen’s wrist flexion test), and 0.2% for electrophysiologically-confirmed CTS (abnormal nerve conduction tests). Logistic regression analyses identified increasing age, female gender, the duration of professional VDT use per day, a history of thyroid diseases, and a history of rheumatoid arthritis as significant and independent factors associated with MSS. Adaptation of the work-place was associated with a lower likelihood of MSS. Only increasing age and female gender were identified as significant and independent factors associated with CTS (symptom-specific and examination-confirmed CTS). Job-related factors were not significantly associated with an increased risk for CTS.

Conclusions: Our study confirms the high prevalence of MSS among Belgian visual display terminal users (more than 30%). Two work-related factors were clearly associated with MSS: the duration of professional VDT use per day (increased risk) and prior adaptation of the workplace according to advice given by the occupational physician (decreased risk). By contrast, the prevalence of CTS was low (less than 2%), and no job-related risk factors for CTS could be identified among VDT users.