Objective The aim of this study was to assess prevalence, incidence, and persistence of carpal tunnel syndrome (CTS) and associated symptoms over a one-year period in a working population.

Methods We conducted a one-year prospective study of 418 active workers in 12 worksites. Detailed health interviews, psychosocial questionnaires, and electrophysiological studies [ie, nerve conduction velocity (NCV) tests] were conducted at baseline and one-year follow-up. Individual-observed exposure assessments of wrist posture, hand activity, and hand forces were conducted.

Results Prevalence of CTS cases at baseline was 10.8% [95% confidence interval (95% CI) 7.8–13.7%] on the dominant side and 6.0% (95% CI 3.7–87.3%) on the non-dominant side; CTS symptoms were 14.1% (95% CI 10.8–17.5%) and 11.0% (95% CI 8.0–14.0%), respectively. Incidence of CTS cases were 7.5% (95% CI 4.8–10.2%) and 5.6% (95% CI 3.3–7.9%), respectively. Higher proportions of subjects with current symptoms or positive electrophysiological test findings at baseline became CTS cases at one year compared to those with neither (28.6% and 13.9%, respectively, versus 0.5%). One-year persistence of CTS case status was 44.4% (95% CI 29.9–59.0%) for the dominant hand and 52.0% (95% CI 32.4–71.6) for non-dominant hand. There were significant differences at baseline between asymptomatic subjects and CTS cases with respect to higher job demands (P=0.027), lower job satisfaction (P=0.036), lower general health (P=0.0009), higher exposure to vibrating hand tool use (P=0.039), and greater time using a forceful power grip (P=0.035) among cases.

Conclusions CTS symptoms more than positive NCV test results alone appear to predict CTS at one year. Persistence of CTS at one year is high.

Key terms active worker; carpal tunnel syndrome; CTS; incidence; nerve entrapment; persistence; physical load factor; prevalence; psychosocial factor; working population