Table 2.
Covariance analysis results of serum biochemical indexes (mean ± SD).
| Variable | Lower exposure (n = 24) | Middle exposure (n = 50) | Higher exposure (n = 50) | F | p value |
|---|---|---|---|---|---|
| White blood cell count (109/L) | 6.929 ± 1.243 | 6.656 ± 1.088# | 5.206 ± 1.209* | 8.569 | < 0.001 |
| Neutrophil (109/L) | 3.951 ± 0.914 | 3.423 ± 0.291*# | 3.949 ± 0.911 | 2.803 | 0.010 |
| Lymphocyte (109/L) | 1.839 ± 0.489 | 1.836 ± 0.480 | 1.925 ± 0.541 | 0.706 | 0.667 |
| Basophils (109/L) | 0.015 ± 0.010 | 0.015 ± 0.014# | 0.040 ± 0.015* | 16.053 | < 0.001 |
| Monocytes (109/L) | 0.350 ± 0.078 | 0.342 ± 0.050 | 0.334 ± 0.063 | 0.718 | 0.657 |
| Eosinophils (109/L) | 0.157 ± 0.112 | 0.212 ± 0.078*# | 0.363 ± 0.102* | 16.505 | < 0.001 |
| Red blood cell count (1012/L) | 5.017 ± 0.392 | 5.122 ± 0.413 | 5.080 ± 0.420 | 0.379 | 0.913 |
| Hemoglobin (g/L) | 142.920 ± 13.247 | 140.780 ± 12.621# | 148.160 ± 13.577 | 13.364 | < 0.001 |
| Mean corpuscular volume (fL) | 85.670 ± 10.516 | 86.380 ± 10.463 | 85.560 ± 10.695 | 0.643 | 0.720 |
| Mean corpuscular hemoglobin concentration (g/L) | 340.880 ± 11.449 | 339.540 ± 8.779 | 338.400 ± 7.902 | 0.756 | 0.625 |
| Mean platelet volume (fL) | 9.370 ± 1.075 | 9.650 ± 0.497 | 9.480 ± 0.945 | 1.065 | 0.391 |
| Platelet volume distribution width | 11.996 ± 2.146 | 11.770 ± 1.668 | 11.796 ± 1.897 | 0.849 | 0.549 |
| The average amount of Hb in red blood cells (pg) | 28.920 ± 4.106 | 28.940 ± 4.043 | 29.720 ± 3.552 | 0.486 | 0.843 |
| Platelet count (109/L) | 234.040 ± 45.108 | 237.940 ± 45.488 | 238.320 ± 43.507 | 1.105 | 0.365 |
| Plateletcrit (PTC) | 0.271 ± 0.042 | 0.258 ± 0.042 | 0.261 ± 0.045 | 0.639 | 0.723 |
The covariant variables including gender, ethnic group, working age, education condition and recent hair dye history.
*P < 0.05, comparison of the higher and middle exposure group with the lower exposure group by Bonferroni method.
#P < 0.05, comparison between the higher exposure group and middle exposure group by Bonferroni method.