This article is more than 5 years old. Information may no longer be current.
Large Swedish population study finds CTS symptoms rare with heavy keyboard use
Researchers gathered data from 2,465 workers via questionnaires, nerve tests or physical exams.
Click Here to Manage Email Alerts
SEATTLE — Results from a recent population study of 2,465 Swedish workers indicated the prevalence of carpal tunnel syndrome symptoms was highest in study participants who used a keyboard the least at work — or not at all.
Their greater risk for carpal tunnel syndrome (CTS) may finally end the debate on whether a positive connection exists between the condition and keyboard use … or add more fuel to the fire.
“Intense keyboard use at work seems to be associated with a lower risk of CTS,” said Isam Atroshi, MD, PhD, who presented results of the study at the American Society for Surgery of the Hand 62nd Annual Meeting, here.
The research team previously published their findings on the prevalence of CTS in the general southern Swedish population in the Journal of the American Medical Association.
CTS prevalence
Among persons of working age (25 to 65 years), Swedish researchers found a 2.6% prevalence of CTS in people who used a keyboard on the job more than 4 hours per day. However, they detected a much higher 5.2% prevalence for those who did not use keyboards at work at all (P =.032, for trend).
Specifically, researchers found a 2.9% CTS prevalence in workers who keyboarded from 1 to 4 hours per day and 4.9% in those who used a keyboard less than 1 hour daily.
They identified study subjects by randomly mailing a questionnaire to 2,465 people in the specified age group, inquiring about their personal and work data, medical history, general health, and symptoms of pain, tingling or numbness throughout the body.
“The questionnaire was general. The participants did not know that this was about CTS or work or upper extremity,” Atroshi explained. The response rate was 82%. Overall, 301 respondents were symptomatic.
Following the questionnaires, they performed physical exams and nerve conduction studies to confirm and diagnose CTS in those who responded they had recurrent symptoms and wanted to enter the study (80%).
The CTS definition researchers used was symptoms of recurrent median nerve numbness and tingling reported on the questionnaire and verified by clinical examination, with abnormal nerve conduction study results.
Investigators performed a multivariate Cox regression analysis to compare groups for CTS incidence vs. keyboard use, and adjust for age, sex, body mass index and smoking.
Strengths/weaknesses
The study’s weaknesses included its cross-sectional nature which prevented investigators from showing a direct relationship between keyboard use and CTS and its reliance on self-reported data, Atroshi said. But, it was highly unlikely any outside activities or work participants performed, including side jobs, hobbies or keyboarding at home, significantly affected results, he said.
Brent A. Graham, MD, FRCS(C), who moderated the session where the paper was presented, called the results valuable.
“This study should go a long way to putting to rest the idea that exposure to computer keyboard use is a risk factor for development of symptoms of CTS and, in fact, it might even be protective,” he said. “This is as strong a study as we may see in the future.”
According to Barry P. Simmons, MD, “The controversy relating keyboard use to CTS continues to rage on, mostly in the lay or legal literature, despite the overwhelming evidence that they are not related.”
Even with the results from this excellent paper in hand, the issue of a protective effect of keyboard use on CTS still needs to be studied further, he told Orthopaedics Today International. “More importantly, it once again emphasizes that there is not a causal relationship.”
Image: Papachristos A |
For more information:
- Isam Atroshi, MD, PhD, can be reached at Department of Orthopedics, Hässleholm-Kristianstad Hospital, S-291 85, Kristianstad, Sweden; +46-4-413-1260; e-mail: isam.atroshi@skane.se. He has indicated the study received support from Skane County (Sweden) Council’s Research and Development Foundation and Kristianstad University, Sweden.
- Brent A. Graham, MD, FRCS(C), is a microvascular hand surgeon. He can be reached at University Hand Program, Toronto Western Hospital, East Wing 2nd Floor, 399 Bathurst St., Toronto, ON M5T 2S8, Canada; +1-416-603-5647; e-mail: brent.graham@uhn.on.ca. He has no direct financial interests in the product or company mentioned in this article.
- Barry P. Simmons, MD, can be reached at Brigham & Women’s Hospital, 75 Francis St., Boston, MA 02115-6110, U.S.A.; +1-617-732-5378; e-mail: bsimmons@partners.org. He has no direct financial interests in the product or companies mentioned in this article.
References:
- Atroshi I, Gummesson C, Ornstein E, et al. Carpal tunnel syndrome and keyboard use at work: Population-based study. #20. Presented at the 62nd Annual Meeting of the American Society for Surgery of the Hand. Sept. 27-29, 2007. Seattle.
- Atroshi I, Gummesson C, Johnsson R, et al. Prevalence of carpal tunnel syndrome in a general population. J Amer Med Assoc. 1999;282:153-158.