Comparison of whole study group with those eligible for inclusion
| Total study group (n=110) | Colour vision study included group (n=78) | |
| Age (y, mean (SD)) | 54 (12) | 53 (11) |
| Education (y, mean (SD)) | 11 (3) | 11 (3) |
| Alcohol (units/week, mean (SD)) | 13 (12) | 13 (12) |
| Cumulative exposure score (OEL-years, mean (SD)) | 12 (16) | 11 (16) |
| Annual average intensity (OEL, mean (SD)) | 0.5 (0.5) | 0.5 (0.5) |
| GSTM1 (null/positive, %) | 50/50 | 49/51 |
| GSTT1 (null/positive, %) | 12/88 | 13/87 |
| NAT2 (slow+slow/slow+fast/fast+fast, %) | 54/40/6 | 55/38/7 |
OEL=occupational exposure limit.