Table 3 Comparison of baseline characteristics and parameters between participants and those who withdrew from the study
Parameters (unit) | Toner-handling group | Non-toner-handling group | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Participants | Withdrawal | P-value | Participants | Withdrawal | P-value | |||||
n = 684 | n = 203 | n = 414 | n = 167 | |||||||
M (SD)/% | M (SD)/% | M (SD)/% | M (SD)/% | |||||||
Age (years) | 38.0 | (6.9) | 41.2 | (7.2) | < 0.001 | 38.6 | (6.1) | 38.3 | (7.4) | 0.629 |
BMI (kg/m2) | 23.3 | (2.9) | 23.5 | (3.0) | 0.434 | 23.7 | (3.0) | 23.6 | (2.9) | 0.786 |
Current smoker | 52.0% | 48.3% | 0.379 | 44.4% | 52.7% | 0.081 | ||||
Prevalence of respiratory diseases (%) | ||||||||||
 Asthma | 9.9% | 7.9% | 0.416 | 9.7% | 12.0% | 0.451 | ||||
 Allergic rhinitis | 51.2% | 50.7% | 0.936 | 48.6% | 47.3% | 0.854 | ||||
 Allergic dermatitis | 21.6% | 18.2% | 0.326 | 22.9% | 20.4% | 0.581 | ||||
 Pneumonia | 0.6% | 0.0% | 0.579 | 0.5% | 0.0% | 1.000 | ||||
 Sinusitis | 2.5% | 3.4% | 0.462 | 1.4% | 3.0% | 0.310 | ||||
Ratio of workers handling harmful substances (%) | ||||||||||
 Workers handling dust other than toner | 3.8% | 0.0% | 0.002 | 0.2% | 0.6% | 0.493 | ||||
 Workers handling organic solvent | 25.6% | 28.6% | 0.414 | 2.9% | 3.0% | 1.000 | ||||
Respiratory function tests | ||||||||||
 VC (l) | 4.2 | (0.6) | 4.1 | (0.6) | < 0.001 | 4.2 | (0.6) | 4.2 | (0.6) | 0.606 |
 %VC (%) | 92.9 | (107.0) | 90.7 | (10.5) | 0.012 | 91.8 | (9.8) | 91.9 | (9.9) | 0.895 |
 FEV1 (l) | 3.5 | (0.5) | 3.4 | (0.5) | < 0.001 | 3.5 | (0.5) | 3.5 | (0.5) | 0.759 |
 %FEV1 (%) | 95.3 | (11.3) | 93.9 | (10.7) | 0.120 | 94.6 | (10.8) | 94.2 | (10.9) | 0.700 |
 FEV1/FVC (%) | 83.1 | (6.1) | 82.8 | (5.5) | 0.552 | 83.0 | (6.0) | 82.7 | (6.0) | 0.596 |
 %FEV1/FVC (%) | 100.0 | (6.9) | 100.5 | (6.9) | 0.344 | 100.3 | (7.2) | 99.7 | (7.0) | 0.410 |
 V25 (l/s) | 1.6 | (0.5) | 1.5 | (0.4) | 0.002 | 1.6 | (0.5) | 1.6 | (0.6) | 0.669 |
 %V25 (%) | 68.5 | (20.2) | 67.4 | (18.9) | 0.500 | 67.3 | (18.3) | 67.4 | (19.9) | 0.974 |
Biomarkers | ||||||||||
 CRP (mg/dl) | 0.08 | (0.16) | 0.11 | (0.24) | 0.135 | 0.10 | (0.19) | 0.10 | (0.24) | 0.935 |
 IgE (IU/ml) | 194.1 | (386.2) | 229.0 | (360.2) | 0.313 | 206.4 | (436.5) | 252.7 | (429.4) | 0.251 |
 IL-4 (pg/ml) | 19.9 | (31.7) | 16.6 | (18.3) | 0.219 | 10.8 | (35.8) | 10.7 | (14.4) | 0.988 |
 IL-6 (pg/ml) | 1.3 | (3.2) | 1.4 | (3.0) | 0.763 | 1.3 | (5.5) | 0.9 | (0.8) | 0.430 |
 IL-8 (pg/ml) | 3.2 | (22.0) | 1.8 | (9.2) | 0.449 | 1.1 | (0.7) | 1.2 | (1.0) | 0.365 |
 IFN-γ (IU/ml) | 0.1 | (0.1) | 0.1 | (0.1) | 0.902 | 0.1 | (0.1) | 0.1 | (0.1) | 0.220 |
 8- OHdG/Creatinine (ng/mg) | 3.9 | (1.4) | 3.9 | (1.9) | 0.883 | 3.8 | (1.5) | 3.8 | (1.4) | 0.692 |