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
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.