Comparison between active and retired miners in 1994 (n=171)
| Active miners (n=131) | Retired miners (n=40) | p Value | |
| Age (y, mean (SD)) | 45.6 (3.2) | 49.7 (2.0) | 0.0001 |
| Estimated cumulative exposure to dust (mg/m3.y, mean (SD)) | 51.2 (41.4) | 67.2 (44.2) | 0.04 |
| Smoking (%): | |||
| Non-smokers | 23 | 25 | |
| Ex-smokers | 22 | 45 | 0.008 |
| Current smokers | 55 | 30 | |
| Selenium concentration (ng/ml, mean (SD)) | 63.6 (19.1) | 67.9 (15.9) | 0.2 |
| Plasma GSH-Px (U/l, mean (SD)) | 694 (234) | 748 (227) | 0.2 |
| Erythrocyte GSH-Px (U/g Hb, mean (SD)) | 38.8 (12.5) | 44.6 (13.7) | 0.01 |
| Adjusted means: | |||
| Age and smoking adjusted Se concentration (ng/ml) | 62.6 | 72.2 | 0.01 |
| Age and smoking adjusted plasma GSH-Px (U/l) | 680 | 785 | 0.04 |
| Age and smoking adjusted erythrocyte GSH-Px (U/g Hb) | 38.5 | 46.5 | 0.003 |