Computer use and carpal tunnel syndrome: A one-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.