Between 2001 and 2010 six research groups conducted coordinated multi-year, prospective studies of upper extremity musculoskeletal disorders in US workers from various industries and collected detailed subject-level exposure information with follow-up symptom, physical examination, electrophysiological measures, and job changes. Objective. This analysis of the pooled cohort examined the incidence of dominant-hand carpal tunnel syndrome (CTS) in relation to demographic characteristics and estimated associations with occupational psychosocial factors, adjusting for confounding by personal risk factors. Methods. 3,515 participants, without baseline CTS, were followed up to 7 years. Case criteria included symptoms and an electrodiagnostic study consistent with CTS. Adjusted hazard ratios were estimated in Cox proportional hazard models. Workplace biomechanical factors were collected but not evaluated in this analysis. Results. Females were at elevated, though statistically non-significant, risk for CTS (HR=1.30; 95%CI: 0.98-1.72). The incidence of CTS increased linearly with both age and BMI over most of the observed range. High job strain increased risk (HR=1.86; 95%CI: 1.11-3.14) and social support was protective (HR=0.43; 95%CI: 0.23-0.78). There was no effect modification of gender on age, BMI or high job strain. Conclusions. Personal factors associated with an increased risk of developing CTS were BMI, age and being female, though no effect modification by gender was evident. Workplace risk factors were high job strain while social support was protective.
