Background
Methods
Study design
Ethical approval
Study participants and data collection
Workplace environment
Solvent | Mean (S.D) | Range |
---|---|---|
MEK (n=15) | 8.68 (11.39) | 0.01- 32.5 |
Toluene (n=15) | 13.69 (25.53) | 0.01- 114.8 |
Xylene (n=15) | 26.48 (41.86) | 0.2- 173.1 |
Stoddard solvent (=15) | 111.91 (236.63) | 0.01- 1300 |
Audiological assessment
Audiometric thresholds
Transient evoked otoacoustic emissions (TEOAEs)
Random Gap Detection test –a measure of the function of temporal processing within the CANS
Speech discrimination in quiet and in noise
Data analysis
Results
Variables | All (n=144) | Group 1 (n=72) | Group 2 (n=72) | ||||||
---|---|---|---|---|---|---|---|---|---|
Mean | Median | Range | Mean | Median | Range | Mean | Median | Range | |
Age (years) | 38.7 (7.8) | 38.0 | 22-55 | 39.9 (8.5) | 43.0 | 22-52 | 37.5 (7.1) | 36.0 | 26-55 |
Gender
| |||||||||
Female | 20 | 6 | 14 | ||||||
Male | 124 | 66 | 58 | ||||||
PNE | 30 | 27 | 3 | ||||||
Shooting
| |||||||||
WP | 3 | 3 | 0 | ||||||
NP | 39 | 33 | 6 | ||||||
Tenure | - | - | - | 15.8 (8.1) | 16.5 | 2-34 | 0 | 0 | 0 |
Smoking | 21.26 (30.7) | 14.0 | 0-140 | 26.8 (32.1) | 14.0 | 0-140 | 18.7 (15.8) | 12 | 0-80 |
Alcohol | 17.4 (17.8) | 13.5 | 0-60 | 15.6 (16.3) | 13.5 | 0-60 | 31.2 (24.4) | 27 | 0-60 |
Group comparisons
Solvent-exposed subjects (n=72) | Non-exposed subjects (n=72) | p-value (Mann–Whitney Test) | |||||||
---|---|---|---|---|---|---|---|---|---|
Mean | S.D. | Min | Max | Mean | S.D. | Min | Max | ||
RGD 0.5
| 12.46 | 10.65 | 2 | 60 | 8.16 | 6.94 | 2 | 25 | p=0.013 |
RGD 1
| 14.46 | 10.38 | 2 | 60 | 7.02 | 4.25 | 2 | 15 | P<0.0001 |
RGD 2
| 14.24 | 13.26 | 2 | 60 | 8.26 | 6.25 | 2 | 30 | p=0.001 |
RGD 4
| 15.17 | 12.66 | 2 | 60 | 9.45 | 8.18 | 2 | 50 | p=0.001 |
RGD C
| 10.34 | 7.57 | 2 | 40 | 7.40 | 6.39 | 2 | 25 | p=0.017 |
HINT SRT
| 19.99 | 6.61 | 12.60 | 54.80 | 16.19 | 3.52 | 11.00 | 26.20 | p<0.0001 |
HINT 1
| −3.37 | 1.29 | −5.50 | 2.40 | −4.02 | 0.75 | −5.10 | −1.80 | p=0.004 |
HINT 2
| −11.03 | 1.79 | −13.8 | −2.20 | −11.78 | 1.02 | −13.6 | −9.40 | p=0.012 |
HINT 3
| −11.21 | 1.83 | −14.7 | −2.20 | −11.73 | 1.13 | −13.6 | −9.40 | p=0.140 |
HINTC
| −7.26 | 1.27 | −8.50 | 0.10 | −7.94 | 0.83 | −11.1 | −5.90 | p=0.001 |
Bivariate and multivariate regression analyses
Bivariate model | Multivariate model | Final multivariate model | ||||||
---|---|---|---|---|---|---|---|---|
Characteristic | Beta | p | Beta | p | Characteristic | Beta | p | |
Age | 0.411 | p<0.0001 | 0.089 | 0.894 | Age | 0.365 | p<0.0001 | |
Male | 0.056 | 0.594 | −0.248 | 0.093 | ||||
Solvent exp.
| EXP | 0.332 | 0.001 | −0.122 | 0.855 | EXP | 0.296 | 0.002 |
NEXP | Reference | |||||||
Tenure | 0.415 | p<0.0001 | −0.068 | 0.834 | ||||
Risk factors
| Cigarettes | 0.197 | 0.158 | 0.246 | 0.083 | |||
Alcohol | 0.200 | 0.152 | 0.278 | 0.043 | ||||
ShootWP | −0.060 | 0.635 | 0.040 | 0.754 | ||||
ShootNP | −0.035 | 0.786 | 0.162 | 0.246 | ||||
No Shoot | Reference | |||||||
Pastnoise | 0.174 | 0.095 | 0.117 | 0.377 | ||||
Interactions
|
Interactions
| |||||||
Age*solvent | 0.627 | 0.581 |
Bivariate model | Multivariate model | Final multivariate model | ||||||
---|---|---|---|---|---|---|---|---|
Characteristic | Beta | p | Beta | p | Characteristic | Beta | p | |
Age | −0.130 | 0.256 | 0.213 | 0.786 | ||||
Male | −0.247 | 0.027 | −0.091 | 0.605 | ||||
Solvent exp. | EXP | −0.317 | 0.004 | −0.290 | 0.723 | EXP | −0.421 | 0.005 |
NEXP | Reference | |||||||
Tenure | −0.346 | 0.002 | −0.535 | 0.183 | ||||
Risk factors
| Cigarettes | −0.259 | 0.075 | −0.033 | 0.849 | |||
Alcohol | −0.206 | 0.166 | −0.342 | 0.058 | Alcohol | −0.352 | 0.019 | |
ShootWP | 0.028 | 0.835 | 0.119 | 0.437 | ||||
ShootNP | 0.053 | 0.695 | 0.192 | 0.254 | ||||
No Shoot | Reference | |||||||
Pastnoise | −0.176 | 0.121 | −0.051 | 0.750 | ||||
Interactions
|
Interactions
| |||||||
Age*solvent | 0.180 | 0.895 |
Bivariate model | Multivariate model | Final multivariate model | ||||||
---|---|---|---|---|---|---|---|---|
Characteristic | Beta | p | Beta | p | Characteristic | Beta | p | |
Age | 0.293 | 0.007 | 0.527 | 0.466 | Age | 0.255 | 0.008 | |
Male | 0.086 | 0.431 | 0.033 | 0.840 | ||||
Solvent exp.
| EXP | 0.403 | p<0.0001 | 0.177 | 0.813 | EXP | 0.239 | 0.027 |
NEXP | Reference | |||||||
Tenure | 0.467 | p<0.0001 | 0.082 | 0.821 | ||||
Risk factors
| Cigarettes | −0.048 | 0.742 | −0.255 | 0.098 | |||
Alcohol | −0.104 | 0.477 | −0.031 | 0.834 | ||||
ShootWP | −0.064 | 0.626 | 0.021 | 0.883 | ||||
ShootNP | 0.224 | 0.086 | 0.257 | 0.098 | ||||
No Shoot | Reference | |||||||
Pastnoise | 0.427 | p<0.0001 | 0.384 | 0.012 | Pastnoise | 0.303 | 0.005 | |
Interactions
|
Interactions
| |||||||
Age*solvent | −0.250 | 0.840 |
Bivariate Model | Multivariate model | Final multivariate model | ||||||
---|---|---|---|---|---|---|---|---|
Characteristic | Beta | p | Beta | P | Characteristic | Beta | p | |
Age | 0.317 | 0.003 | −0.080 | 0.915 | Age | 0.252 | 0.014 | |
Male | 0.201 | 0.061 | 0.006 | 0.973 | ||||
Solvent exp.
| EXP | 0.343 | 0.001 | −0.176 | 0.826 | EXP | 0.330 | 0.001 |
NEXP | Reference | |||||||
Tenure | 0.370 | p<0.0001 | 0.010 | 0.978 | ||||
Risk factors
| Cigarettes | 0.089 | 0.542 | 0.204 | 0.204 | |||
Alcohol | 0.207 | 0.159 | 0.220 | 0.184 | ||||
ShootWP | 0.052 | 0.698 | 0.013 | 0.932 | ||||
ShootNP | −0.104 | 0.431 | −0.039 | 0.810 | ||||
No Shoot | Reference | |||||||
Pastnoise | −0.011 | 0.918 | −0.287 | 0.065 | ||||
Interactions
|
Interactions
| |||||||
Age*solvent | 0.567 | 0.669 |
Bivariate model | Multivariate model | Final multivariate model | ||||||
---|---|---|---|---|---|---|---|---|
Characteristic | Beta | p | Beta | p | Characteristic | Beta | p | |
Age | 0.250 | 0.020 | 0.745 | 0.289 | ||||
Male | 0.092 | 0.392 | 0.147 | 0.361 | ||||
Solvent exp.
| EXP | 0.306 | 0.004 | 1.013 | 0.177 | EXP | 0.306 | 0.004 |
NEXP | Reference | |||||||
Tenure | 0.263 | 0.013 | −0.231 | 0.515 | ||||
Risk factors
| Cigarettes | 0.065 | 0.660 | 0.116 | 0.434 | |||
Alcohol | −0.051 | 0.732 | −0.124 | 0.413 | ||||
ShootWP | −0.062 | 0.640 | −0.101 | 0.462 | ||||
ShootNP | −0.057 | 0.670 | −0.003 | 0.982 | ||||
No Shoot | Reference | |||||||
Pastnoise | 0.098 | 0.368 | 0.078 | 0.534 | ||||
Interactions
|
Interactions
| |||||||
Age*solvent | −0.764 | 0.534 |