Crude and adjusted means of morning MT6s concentrations by selected characteristics of rotating night shift work: a cross-sectional study of Polish nurses and midwives
| Night shift work characteristic | n | Morning MT6s (ng/mg Cr), mean (95% CI) | Adjusted* morning MT6s (ng/mg Cr), mean (95% CI) |
| Current rotating night shift work | |||
| No | 370 | 45.2 (42.0 to 48.4) | 45.7 (42.9 to 48.6) |
| Yes | 354 | 44.9 (41.6 to 48.2) | 47.2 (44.2 to 50.2) |
| p | 0.893 | 0.490 | |
| Total duration of night shift work (years) | |||
| −5 | 87 | 46.8 (40.0 to 53.6) | 45.5 (39.7 to 51.3) |
| >5 to ≤15 | 182 | 44.6 (40.1 to 49.2) | 45.9 (41.9 to 50.0) |
| >15 to ≤25 | 257 | 44.9 (41.0 to 48.8) | 45.7 (42.1 to 49.2) |
| >25 | 198 | 44.8 (40.4 to 49.2) | 48.4 (44.2 to 52.5) |
| p-trend | 0.740 | 0.404 | |
| Total number of hours of night shift work by tertiles† | |||
| First | 242 | 44.5 (40.5 to 48.5) | 44.0 (41.6 to 48.5) |
| Second | 241 | 46.4 (42.3 to 50.4) | 47.7 (44.0 to 51.3) |
| Third | 241 | 44.2 (40.3 to 48.2) | 46.6 (43.0 to 50.2) |
| p-trend | 0.925 | 0.520 | |
| Cumulative number of night shifts | |||
| −999 or less | 210 | 44.7 (40.5 to 49.0) | 45.2 (41.5 to 48.9) |
| 1000–1999 | 253 | 45.9 (41.9 to 49.8) | 46.6 (43.1 to 50.1) |
| 2000+ | 261 | 44.5 (40.7 to 48.3) | 47.3 (43.8 to 50.8) |
| p-trend | 0.898 | 0.422 | |