Table 1.
Background characteristics of the subjects according to the exposure category
| Characteristics | Category of exposure condition | ||||||
| Control | Exposed | P values† | |||||
| Total | TPD | DDM | MTN | RCL | |||
| Number surveyed | 217 | 477 | 175 | 145 | 150 | 7 | |
| Sex (M/F) | 205/12 | 461/16 | 167/8 | 141/4 | 149/1 | 3-Apr | 0.18 |
| Age (years) | 39.1 (8.2) | 34.1 (8.1) | 32.9 (10.3) | 35.4 (6.5) | 34.2 (6.3) | 32.4 (7.6) | <0.0001 |
| Height (cm) | 170.1 (6.6) | 170.3 (6.4) | 169.0 (6.1 | 171.3 (6.4) | 171.4 (6.4) | 161.5 (6.8) | 0.63 |
| BMI (kg/m2) | 23.0 (3.1) | 23.0 (3.7) | 23.2 (4.6) | 22.4 (2.6) | 23.4 (3.2) | 19.9 (1.5) | 0.999 |
| Smoking habit‡ | 0.026 | ||||||
| Never | 70(32) | 150(31) | 38(22) | 69(48) | 38(25) | 5 (71) | |
| Former | 47(22) | 67(14) | 17(10) | 26(18) | 24(16) | 0 | |
| Current | 100(46) | 260(55) | 120(68) | 50(34) | 88(59) | 2 (29) | |
| Personal exposure (mg/m3) | - | ||||||
| Number of samples | 2042 | 1751 | 81 | 88 | 122 | ||
| Total dust | |||||||
| 10th percentile | 0.08 | 0.09 | 0.04 | 0.07 | 0.51 | ||
| Median | 0.49 | 0.5 | 0.08 | 0.17 | 1.46 | ||
| 90th percentile | 2.38 | 2.14 | 0.38 | 0.8 | 5.6 | ||
| Respirable dust | |||||||
| 10th percentile | 0.03 | 0.03 | 0.03 | 0.03 | 0.02 | ||
| Median | 0.05 | 0.09 | 0.03 | 0.03 | 0.04 | ||
| 90th percentile | 0.36 | 0.35 | 0.04 | 0.15 | 0.64 | ||
Values are presented as the number of subjects for sex and smoking habit and the arithmetic mean (SD) for age, height and BMI at the baseline survey.
†Probability under the hypothesis that there are no differences between the control group and the exposed group as a whole.
‡Percentage of column total in parentheses.
BMI, body mass index; DDM, machine design and development; MTN, maintenance; RCL, recycling; TPD, toner production.