Table 1 General characteristics of the study subjects grouped by PPD exposure.
Variable | Lower exposure (n = 24) | Middle exposure (n = 50) | Higher exposure (n = 50) | Chi square/F | p value |
|---|---|---|---|---|---|
PPD exposure concentration (mg/m3) | < 0.00001 | 0.00001–0.00033 | 0.00033–0.047 | ||
Age (years) | 41.29 ± 6.27 | 34.18 ± 9.00 | 39.86 ± 8.23 | 8.596b | < 0.001 |
Working age (years) | 18.25 ± 10.66 | 7.04 ± 7.87 | 11.12 ± 7.49 | 14.727b | < 0.001 |
Gender | |||||
Male | 9 (38%) | 18 (36%) | 41 (82%) | 24.973 | < 0.001 |
Female | 15 (62%) | 32 (64%) | 9 (18%) | ||
Ethnic group | |||||
Han | 1 (4%) | 10 (20%) | 3 (6%) | ||
Others | 23 (96%) | 40 (80%) | 47 (94%) | 5.578a | 0.044 |
Marital status | |||||
Married | 18 (75%) | 35 (70%) | 40 (80%) | 1.333 | 0.513 |
Others (unmarried and divorced) | 6 (25%) | 15 (30%) | 10 (20%) | ||
Educational condition | |||||
Junior high school and lower level | 5 (21%) | 35 (70%) | 25 (50%) | 15.914 | < 0.001 |
Senior middle school level and higher | 19 (79%) | 15 (30%) | 25 (50%) | ||
Cigarette smoking | |||||
Yes | 13 (54%) | 25 (50%) | 26 (52%) | 0.118 | 0.943 |
No | 11 (46%) | 25 (50%) | 24 (48%) | ||
Hair dye history | |||||
Yes | 4 (17%) | 16 (32%) | 27 (54%) | 10.843 | 0.004 |
No | 20 (83%) | 34 (68%) | 23 (46%) | ||
Body mass index (BMI) (kg/m2) | |||||
< 25 | 15 (62%) | 39 (78%) | 28 (56%) | 5.577 | 0.062 |
≥ 25 | 9 (38%) | 11 (22%) | 22 (44%) | ||
