Table 2.
Risk of invasive and borderline ovarian tumors in association with working the nightshift
| Invasive | Borderline | |||||||
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| Controls (%)(n=1832) | Cases (%)(n=1101) | ORa (95% CI) | Cases (%)(n=389) | ORa (95% CI) | ||||
| Worked nightshift | ||||||||
| Never | 1420 | (77.5) | 808 | (73.4) | 263 | (67.6) | ||
| Ever | 412 | (22.5) | 293 | (26.6) | 1.24 (1.04–1.49) | 126 | (32.4) | 1.48 (1.15–1.90) |
| Worked nightshift for less than half of all work days | ||||||||
| Never | 1587 | (86.6) | 916 | (83.2) | 312 | (80.2) | ||
| Ever | 245 | (13.4) | 185 | (16.8) | 1.28 (1.03–1.59) | 77 | (19.8) | 1.32 (0.98–1.78) |
| Worked nightshift for all work days | ||||||||
| Never | 1696 | (92.6) | 1006 | (91.4) | 351 | (90.2) | ||
| Ever | 136 | (7.4) | 95 | (8.6) | 1.16 (0.87–1.55) | 38 | (9.8) | 1.29 (0.87–1.92) |
| Cumulative nightshift work-years | ||||||||
| Never | 1420 | (77.5) | 808 | (73.4) | 263 | (67.6) | ||
| 4mos-1 yr | 97 | (5.3) | 55 | (5.0) | 1.03 (0.72–1.47) | 27 | (6.9) | 1.44 (0.90–2.29) |
| >1–3 yrs | 121 | (6.6) | 75 | (6.8) | 1.13 (0.82–1.54) | 35 | (9.0) | 1.33 (0.87–2.02) |
| >3–7 yrs | 85 | (4.6) | 94 | (8.5) | 1.95 (1.41–2.68) | 44 | (11.3) | 2.37 (1.57–3.57) |
| >7 yrs | 108 | (5.9) | 68 | (6.2) | 1.02 (0.74–1.42) | 20 | (5.1) | 0.97 (0.58–1.61) |
| unknown | 1 | (<1) | 1 | (<1) | - | 0 | (0) | - |
a
Adjusted for age at reference, county, reference year, duration of oral contraceptive use, number of full term pregnancies and BMI at age 30