Objectives: This study attempted to identify risk factors for musculoskeletal symptoms in the neck and hand-wrist regions among employees using computers at work.
Methods: Computer users (N=5033) first received a questionnaire in the beginning of 1999 (69% response rate, N=3475), and a follow-up questionnaire was mailed in December of 2000 to the 3361 respondents to the baseline survey (77% response rate, N=2576). Health outcome was defined as musculoskeletal symptoms for >7 days within the last year of follow-up among the nonsymptomatic respondents at baseline.
Results: Men's and women's previous symptoms, women's low influence at work and high-placed computer screen, and men's short time in the same job and good computer skills were associated with neck symptoms. Hand-wrist symptoms were predicted by previous symptoms and low influence at work for both the men and women and sensorial demands for the women only. The duration of computer use predicted hand-wrist symptoms [eg, odds ratio (OR) of 2.3, 95% confidence interval (95% CI) 1.2-4.3, for almost continual computer use], but not neck symptoms. For those with almost continual computer use, hand-wrist symptoms were associated with mouse use for at least half of the worktime (OR 4.0, 95% CI 1.0-15.5) and not using the mouse at all (OR 4.0, 95% CI 1.1-14.4), as compared with mouse use for one-fourth of the worktime.
Conclusions: Limiting computer use to less than three-fourths of the worktime would help to prevent hand-wrist symptoms. Furthermore, low influence at work predicts both neck and hand-wrist symptoms.