Table 3

Crude and adjusted IRRs of CTS diagnoses and surgery by wrist exposure intensity and duration variables and by sex

Wrist exposuresSex
IntensityDuration
Median velocity of flexion/extension of the wrist (per 1 °/s)*Mean power frequency (per 0.01 Hz)*Non-neutral wrist postures (per %time)*Working proportion during the previous year (per unit)†‡Women vs men†
Total (n=4198)
CTS diagnoses
 IRRCrude (95% CI)1.41 (1.12 to 1.79)0.85 (0.65 to 1.10)0.99 (0.89 to 1.11)0.77 (0.47 to 1.26)2.84 (1.94 to 4.16)
 IRRAdj (95% CI)1.37 (1.10 to 1.71)1.53 (1.21 to 1.92)0.93 (0.82 to 1.05)0.92 (0.54 to 1.56)4.11 (2.61 to 6.48)
CTS surgery
 IRRCrude (95% CI)1.52 (1.15 to 2.01)0.81 (0.59 to 1.11)1.00 (0.87 to 1.15)0.76 (0.37 to 1.23)3.31 (2.07 to 5.30)
 IRRAdj (95% CI)1.44 (1.11 to 1.88)1.55 (1.18 to 2.05)0.92 (0.78 to 1.07)0.75 (0.50 to 1.80)6.37 (3.64 to 11.3)
Men (n=2596)
CTS diagnoses
 IRRCrude (95% CI)1.12 (0.74 to 1.71)1.55 (0.54 to 4.44)1.00 (0.85 to 1.17)0.65 (0.32 to 1.28)
 IRRAdj (95% CI)1.15 (0.75 to 1.77)1.49 (0.51 to 4.35)1.01 (0.86 to 1.19)0.75 (0.35 to 1.60)
CTS surgery
 IRRCrude (95% CI)1.19 (0.70 to 2.02)2.22 (0.59 to 8.30)0.95 (0.77 to 1.17)0.54 (0.23 to 1.26)
 IRRAdj (95% CI)1.22 (0.70 to 2.10)2.04 (0.54 to 7.74)0.97 (0.78 to 1.21)0.82 (0.32 to 2.08)
Women (n=1602)
CTS diagnoses
 IRRCrude (95% CI)1.46 (1.15 to 1.86)1.54 (1.21 to 1.95)0.84 (0.70 to 1.01)0.87 (0.41 to 1.85)
 IRRAdj (95% CI)1.45 (1.13 to 1.84)1.52 (1.20 to 1.92)0.82 (0.68 to 0.98)1.00 (0.47 to 2.15)
CTS surgery
 IRRCrude (95% CI)1.53 (1.15 to 2.02)1.53 (1.14 to 2.05)0.89 (0.71 to 1.11)0.79 (0.32 to 1.97)
 IRRAdj (95% CI)1.51 (1.13 to 2.01)1.56 (1.17 to 2.08)0.85 (0.68 to 1.07)1.00 (0.40 to 2.52)
  • Continuous linear effects determined by log-linear Poisson regression. Total and by sex.

  • Bold indicates statistically significant IRRs (p<0.05).

  • *Adjusted for effects of working proportion during the previous year, sex, age, body mass index, fractures near the wrist and comorbidity.

  • †Estimates from the model with median velocity for flexion/extension of the wrist.

  • ‡Estimates were similar when working proportion during the previous year was replaced with the working proportion during the previous 2 years or the previous 5 years.

  • Adj, adjusted; CTS, carpal tunnel syndrome; IRR, incidence rate ratio.