Table 2.
Characteristics of cohort members whose final status was exposed, based on a one year lag period
| Characteristic | No (%) of people exposed |
|---|---|
| Sex | |
| Male | 357 119 (52.5) |
| Female | 323 092 (47.5) |
| Age at first CT scan (years) | |
| 0-4 | 42 798 (6.3) |
| 5-9 | 104 618 (15.4) |
| 10-14 | 202 420 (29.8) |
| 15-19 | 330 375 (48.5) |
| Calendar year of first CT scan | |
| 1985-89 | 95 249 (14.0) |
| 1990-94 | 133 528 (19.6) |
| 1995-99 | 184 463 (27.1) |
| 2000-05 | 266 971 (39.3) |
| Final no of CT scans | |
| 1 | 557 877 (82.0) |
| 2 | 86 109 (12.7) |
| 3 | 23 740 (3.5) |
| 4 | 6763 (1.0) |
| ≥5 | 5722 (0.8) |
| Site of first CT scan | |
| Brain* | 404 105 (59.4) |
| Facial bones | 89 133 (13.1) |
| Chest | 11 381 (1.7) |
| Extremities | 64 940 (9.5) |
| Abdomen or pelvis† | 33 870 (5.0) |
| Spine or neck | 58 677 (8.6) |
| Other or unknown | 18 105 (2.7) |
| Total no (%) of people exposed | 680 211 (100.0) |
*Includes brain in combination with other sites such as the chest.
†Includes combined scans of the chest, abdomen, and pelvis.