Neck and shoulder symptoms and disorders among Danish computer workers.

OBJECTIVES: Neck and shoulder pain and disorders were studied among frequent computer users, and the associated effect of mouse and keyboard use was evaluated. METHODS: Technical assistants and machine technicians were followed for 1 year. Questionnaires were sent to 9480 persons (initial response 73%, follow-up response 82%). Computer use information was obtained from the questionnaires. Symptom cases at baseline and follow-up were clinically examined using a standardized clinical protocol. The main outcomes were self-reported pain symptoms in the neck and right shoulder and clinical cases of rotator cuff syndrome, tension neck syndrome, and neck-shoulder pain with pressure tenderness. RESULTS: The prevalence of moderate-to-severe pain in the neck and right shoulder was 4.1% and 3.4%, respectively, and the 1-year incidence for no or minor baseline symptoms was 1.5% and 1.9%, respectively. At baseline, the prevalence rate ratio (PRR) for neck pain was 1.7 [95% confidence interval (95% CI) 1.1-2.6] for mouse use >25 hours/week, that for right shoulder pain increased from 1.6 (95% CI 1.1-2.4) for 15-19 hours/ week to 2.5 (95% CI 1.4-4.3) for >30 hours/week of mouse use, and that for tension neck syndrome increased from 3.5 (95% CI 1.0-12) for 25-29 hours/week to 4.7 (95% CI 1.2-18) for >30 hours/week of mouse use. The relative risk (RR) for new neck pain was 1.8 (95% CI 0.8-3.9) for keyboard use > or = 15 hours/week and increased to 2.4 (95% CI 0.8-6.8) for > or = 30 hours/week. New right-shoulder pain symptoms were associated with mouse use >20 hours/week (RR 1.9, 95% Cl 1.0-3.5, and RR 3.3, 95% CI 1.2-8.9) and with keyboard use >15 hours/week (RR 2.2, 95% CI 1.0-4.9). CONCLUSIONS: Mouse use is associated with an increased risk of moderate-to-severe pain in the neck and right shoulder, and an association with tension neck syndrome is possible.

Elbow and wrist/hand symptoms among 6,943 computer operators: a 1-year follow-up study (the NUDATA study).

BACKGROUND: The aim of this study was to examine relations between computer work aspects and elbow and wrist/hand pain conditions and disorders. METHODS: In a 1-year follow-up study among 6,943 technical assistants and machine technicians self-reported active mouse and keyboard time, ergonomic exposures and associations with elbow and wrist/hand pain were determined. Standardized clinical examinations were performed among symptomatic participants at baseline and at follow-up. RESULTS: For continuous duration of mouse time adjusted linear effects were statistically significant for all investigated pain conditions. For continuous duration of keyboard time the corresponding effects were statistically significant for wrist/hand pain conditions except incident 'severe' wrist/hand pain. There were no threshold effects above 0 hr per week (hr/w) of mouse exposure in association with pain conditions, while keyboard exposure showed a threshold effect with 12-month wrist/hand pain at follow-up. Clinical diagnoses were not associated with exposure. CONCLUSIONS: Detailed examination of self-reported exposures showed that mouse and keyboard time predicted elbow and wrist/hand pain from low exposure levels without a threshold effect, but mouse and keyboard time were not predictors of clinical conditions.

Computer use and carpal tunnel syndrome: a 1-year follow-up study.

CONTEXT: Computer use is increasingly common among many working populations, and concern exists about possible adverse effects of computer use, such as carpal tunnel syndrome (CTS). OBJECTIVES: To estimate the prevalence and incidence of possible CTS and to evaluate the contribution of use of mouse devices and keyboards to the risk of possible CTS. DESIGN AND SETTING: A 1-year follow-up study with questionnaires conducted in 2000 and 2001 at 3500 workplaces in Denmark, followed on each of the 2 occasions by a clinical interview on symptom distribution and frequency. PARTICIPANTS: The questionnaire was sent to 9480 members of a trade union, with an initial response rate of 73% (n = 6943), and 82% (n = 5658) at follow-up. MAIN OUTCOME MEASURES: At baseline, there were 3 outcome measures: tingling/numbness in the right hand once a week or more as reported in the questionnaire; tingling, numbness, and pain in the median nerve in the right hand confirmed by clinical interview; and tingling, numbness, and pain in the median nerve in the right hand at night confirmed by clinical interview. At 1 year of follow-up the main outcome of interest was onset of symptoms among participants who had no or minor symptoms at baseline. RESULTS: The overall self-reported prevalence of tingling/numbness in the right hand at baseline was 10.9%. The interview confirmed that prevalence of tingling/numbness in the median nerve was 4.8%, of which about one third, corresponding to a prevalence of 1.4%, experienced symptoms at night. Onset of new symptoms in the 1-year follow-up was 5.5%. In the cross-sectional comparisons and in the follow-up analyses, there was an association between use of a mouse device for more than 20 h/wk and risk of possible CTS but no statistically significant association with keyboard use. CONCLUSIONS: The occurrence of possible CTS in the right hand was low. The study emphasizes that computer use does not pose a severe occupational hazard for developing symptoms of CTS.