Multiple regression analysis of the relation between urinary concentrations of 8-OH-dG and selected covariates
| Covariate | Median ratio | 95% CI | p Value |
| Age (y): | |||
| ⩽30 | 1.000 | ||
| 30–40 | 0.958 | 0.795 to 1.155 | 0.657 |
| >40 | 0.905 | 0.696 to 1.177 | 0.456 |
| Body mass index (kg/m2): | |||
| ⩽20 | 1.000 | ||
| 20–25 | 1.031 | 0.802 to 1.324 | 0.814 |
| >25 | 0.961 | 0.716 to 1.291 | 0.794 |
| Smoking (cigarettes/day): | |||
| Non-smoker | 1.000 | ||
| ⩽20 | 1.269 | 1.044 to 1.543 | 0.017 |
| >20 | 1.484 | 1.135 to 1.940 | 0.004 |
| Firefighting: | |||
| Unexposed | 1.000 | ||
| Less active duty | 0.969 | 0.807 to 1.164 | 0.740 |
| More active duty | 1.067 | 0.833 to 1.367 | 0.609 |
| CYP2E1: | |||
| c1/c1 | 1.000 | ||
| c1/c2, c2/c2 | 1.130 | 0.950 to 1.344 | 0.167 |