Table 1.
Baseline characteristics of the Norwegian female population* in 1996 by pregnancy status, age, history of Pap smear and invitation to the cervical cancer screening programme
| Pregnancy status | |||
| Reference cohort 2 060 118 (%) | Pregnant cohort 24 297 (%) | Mixed cohort 91 347 (%) | |
| Age-groups | |||
| < 14 | 445 928 (21.7) | 18 (0.07) | 11 (0.01) |
| 15–19 | 125 039 (6.1) | 1688 (7.0) | 4090 (4.5) |
| 20–24 | 130 147 (6.3) | 6087 (25.0) | 20 103 (22.1) |
| 25–29 | 127 742 (6.1) | 9112 (37.5) | 34 809 (38.1) |
| 30–34 | 131 081 (6.4) | 5555 (22.9) | 23 530 (25.8) |
| 35–39 | 144 959 (7.0) | 1653 (6.8) | 7756 (8.5) |
| 40–44 | 146 978 (7.1) | 178 (0.7) | 1024 (1.1) |
| 45–49 | 149 296 (7.2) | 6 (0.02) | 24 (0.03) |
| 50–69 | 394 224 (19.1) | - | - |
| 70+ | 267 724 (13.0) | - | - |
| Time since last Pap smear before T0 | |||
| 0–12 months | 441 735 (21.4) | 9342 (38.4) | 36 318 (39.8) |
| 13–24 months | 278 490 (13.5) | 5934 (24.4) | 23 304 (25.5) |
| 25–36 months | 181 158 (8.8) | 3662 (15.1) | 13 113 (14.4) |
| > 36 months | 1 158 735 (56.2) | 5359 (22.1) | 18 612 (20.4) |
| Time since invitation | |||
| No invitation | 1 567 788 (76.1) | 18 374 (75.6) | 75 393 (82.5) |
| 24–2 months prior to T0 | 229 417 (11.1) | 2596 (10.7) | 989 (1.1) |
| 1 months prior-3 months after T0 | 132 981 (6.5) | 2256 (9.3) | 3524 (3.9) |
| > 3 months after T0 | 129 932 (6.3) | 1071 (4.4) | 11 441 (12.5) |
* 39 707 were excluded because they were either born before 1900, diagnosed with invasive cervical cancer and/or underwent hysterectomy before 1996, died in 1997 or had inadequate data for estimating duration of the pregnancy