Table 2

Results summary from mixed models at dominant and non-dominant second and fifth fingers at seven test frequencies: associations between lifetime cumulative HAV exposure from rock drills and VPT; coefficients represent increase of VPT (dB) per 10-fold increase in lifetime cumulative exposure (hour×ms–2)†‡

FrequencyDominant second finger
(n=147, number of obs=248)§¶		Dominant fifth finger
(n=146, number of obs=244)§¶		Non-dominant second finger
(n=144, number of obs=242)§¶		Non-dominant fifth finger
(n=147, number of obs=246)§¶
HzCoefficients (95% CI)**Coefficients (95% CI)**Coefficients (95% CI)**Coefficients (95% CI)**
80.69 (0.07 to 1.31)*0.85 (0.20 to 1.50)*0.82 (0.25 to 1.40)*0.66 (0.03 to 1.28)*
160.93 (0.34 to 1.52)*0.94 (0.31 to 1.56)*0.90 (0.24 to 1.56)*0.79 (0.18 to 1.40)*
320.48 (–0.09 to 1.05)1.00 (0.36 to 1.64)*0.74 (0.11 to 1.37)*0.65 (–0.00 to 1.31)
640.43 (–0.30 to 1.15)0.91 (0.18 to 1.64)*0.80 (0.00 to 1.59)*0.63 (–0.15 to 1.42)
1250.82 (0.01 to 1.62)*0.88 (–0.04 to 1.80)0.94 (0.08 to 1.81)*0.92 (–0.09 to 1.92)
2500.71 (–0.20 to 1.62)0.75 (–0.37 to 1.88)0.77 (–0.25 to 1.79)1.10 (–0.04 to 2.24)
5000.81 (–0.20 to 1.81)1.11 (–0.13 to 2.36)1.54 (0.36 to 2.72)*1.50 (0.28 to 2.71)*

  • *P≤0.05.

  • †Log10-transformed exposure was used in models adjusted for age in 10-year intervals.

  • ‡HAV exposure was calculated as lifetime cumulative exposure at each VPT test. Subject ID was used as random intercept in linear mixed models.

  • §Each subject was tested for VPT 1–3 three times (mean 1.7 times) with approximately 2 years between each test.

  • ¶The number of participants was less than the total of n=148 for each tested finger because of participants having injured or missing fingertips.

  • **Rock drill exposure was adjusted for impact wrench exposure in the models.

  • HAV, hand-arm vibration ; VPT, vibration perception thresholds .