Table 2 Birthorder and risk of CNS tumours in children by histological subgroup
Conditional OR | Conditional OR adjusted for birth weight and gestational age | |||||||
|---|---|---|---|---|---|---|---|---|
Histology/ birthorder | No. of cases | No. of controls | OR | 95% CI | No. of cases | No. of controls | OR | 95% CI |
CNS tumours a | 3600 | 17 848 | 3337 | 16 299 | ||||
1 | 1571 | 7672 | 1.00 | Ref. | 1431 | 6849 | 1.00 | Ref. |
2 | 1277 | 6420 | 0.97 | (0.90–1.05) | 1210 | 5981 | 0.96 | (0.88–1.05) |
3 | 531 | 2650 | 0.97 | (0.87–1.09) | 493 | 2470 | 0.94 | (0.84–1.06) |
⩾4 | 221 | 1098 | 0.98 | (0.84–1.15) | 203 | 999 | 0.94 | (0.80–1.11) |
Ependymoma | 365 | 1815 | 344 | 1678 | ||||
1 | 155 | 811 | 1.00 | Ref. | 141 | 726 | 1.00 | Ref. |
2 | 136 | 631 | 1.12 | (0.87–1.45) | 133 | 605 | 1.12 | (0.86–1.45) |
3 | 54 | 258 | 1.09 | (0.77–1.53) | 52 | 243 | 1.08 | (0.76–1.53) |
⩾4 | 20 | 115 | 0.91 | (0.55–1.50) | 18 | 104 | 0.86 | (0.50–1.47) |
Astrocytoma | 1525 | 7547 | 1416 | 6933 | ||||
1 | 665 | 3214 | 1.00 | Ref. | 608 | 2898 | 1.00 | Ref. |
2 | 529 | 2759 | 0.93 | (0.82–1.05) | 501 | 2561 | 0.92 | (0.81–1.05) |
3 | 238 | 1112 | 1.03 | (0.88–1.22) | 224 | 1048 | 1.01 | (0.85–1.20) |
⩾4 | 93 | 426 | 0.97 | (0.76–1.23) | 83 | 426 | 0.88 | (0.68–1.13) |
Embryonal CNS | 648 | 3221 | 613 | 2954 | ||||
1 | 284 | 1386 | 1.00 | Ref. | 268 | 1239 | 1.00 | Ref. |
2 | 237 | 1146 | 1.01 | (0.84–1.22) | 224 | 1081 | 0.96 | (0.79–1.17) |
3 | 86 | 476 | 0.88 | (0.67–1.14) | 83 | 438 | 0.85 | (0.65–1.13) |
⩾4 | 41 | 213 | 0.95 | (0.66–1.35) | 38 | 196 | 0.89 | (0.62–1.30) |
Other glioma | 296 | 1463 | 266 | 1315 | ||||
1 | 121 | 632 | 1.00 | Ref. | 110 | 553 | 1.00 | Ref. |
2 | 109 | 512 | 1.11 | (0.83–1.48) | 100 | 471 | 1.03 | (0.76–1.40) |
3 | 50 | 231 | 1.13 | (0.79–1.62) | 41 | 212 | 0.95 | (0.64–1.42) |
⩾4 | 16 | 88 | 0.94 | (0.53–1.67) | 15 | 79 | 0.99 | (0.91–1.07) |
Other specified tumours | 497 | 2460 | 451 | 2217 | ||||
1 | 214 | 1069 | 1.00 | Ref. | 185 | 941 | 1.00 | Ref. |
2 | 184 | 878 | 1.06 | (0.85–1.31) | 175 | 809 | 1.10 | (0.87–1.39) |
3 | 61 | 365 | 0.84 | (0.62–1.14) | 55 | 334 | 0.83 | (0.59–1.15) |
⩾4 | 38 | 148 | 1.28 | (0.87–1.88) | 36 | 133 | 1.35 | (0.90–2.02) |
Unspecified tumours | 269 | 1342 | 247 | 1202 | ||||
1 | 132 | 560 | 1.00 | Ref. | 119 | 492 | 1.00 | Ref. |
2 | 82 | 494 | 0.70 | (0.51–0.95) | 77 | 454 | 0.70 | (0.50–0.98) |
3 | 42 | 216 | 0.83 | (0.57–1.21) | 38 | 195 | 0.81 | (0.54–1.21) |
⩾4 | 13 | 72 | 0.76 | (0.40–1.41) | 13 | 61 | 0.85 | (0.45–1.63) |
