Table 1.
Demographic characteristics of study participants* with obstetric data, UK Childhood Cancer Study 1976-96. Values are numbers (percentages) unless stated otherwise
| Characteristics | All controls (n=4857) | All cases (n=2690) | Leukaemia (n=1253) | Lymphoma (n=231) | Central nervous system (n=482) |
|---|---|---|---|---|---|
| Age at diagnosis (years): | |||||
| <1 | 471 (9.7) | 250 (9.3) | 74 (5.9) | 0 (0) | 44 (9) |
| 1-4 | 2233 (46.0) | 1195 (44.4) | 665 (53.1) | 48 (21) | 153 (32) |
| 5-9 | 1324 (27.3) | 743 (27.6) | 340 (27.1) | 80 (35) | 182 (38) |
| 10-14 | 829 (17.1) | 502 (18.7) | 174 (13.9) | 103 (45) | 103 (21) |
| Mean (median) age at diagnosis (years) | 5.5 (4.4) | 5.7 (4.6) | 5.3 (4.3) | 9.0 (9.4) | 6.4 (6.1) |
| Male sex | 2688 (55.3) | 1499 (55.7) | 692 (55.2) | 165 (71) | 236 (49) |
| Birth weight (g): | |||||
| <2500 | 289 (6.0) | 137 (5.1) | 62 (4.9) | 13 (6) | 26 (5) |
| 2500-4000 | 4071 (83.8) | 2250 (83.6) | 1046 (83.5) | 196 (85) | 406 (84) |
| ≥4000 | 497 (10.2) | 303 (11.3) | 145 (11.6) | 22 (10) | 50 (10) |
| Multiple birth | 108 (2.2) | 62 (2.3) | 25 (2.0) | 6 (3) | 13 (3) |
| Trisomy 21 | 3 (0.1) | 34 (1.3) | 34 (2.7) | 0 (0) | 0 (0) |
| Mean (median) maternal age at birth (years) | 28.0 (27.8) | 27.5 (27.3) | 27.7 (27.6) | 27.0 (26.6) | 27.2 (26.9) |
| Maternal smoking | 1314 (27.1) | 696 (25.9) | 323 (25.8) | 57 (25) | 128 (27) |
| Maternal pre-eclampsia | 481 (9.9) | 278 (10.3) | 127 (10.1) | 31 (13) | 54 (11) |
| Deprivation at birth: | (n=4834) | (n=2677) | (n=1251) | (n=230) | (n=476) |
| 1 (least) | 906 (18.7) | 469 (17.5) | 238 (19.0) | 27 (12) | 78 (16) |
| 2 | 1006 (20.8) | 564 (21.1) | 254 (20.3) | 48 (21) | 114 (24) |
| 3 | 1076 (22.3) | 560 (20.9) | 241 (19.3) | 56 (24) | 102 (21) |
| 4 | 994 (20.6) | 562 (20.9) | 264 (21.1) | 41 (18) | 104 (22) |
| 5 (most) | 852 (17.6) | 522 (19.5) | 254 (20.3) | 58 (25) | 78 (16) |
*One patient with radiotherapy excluded.