Table 1.
Characteristics of the population.
| Leukemia | Central nervous system cancers | |||||||
|---|---|---|---|---|---|---|---|---|
| Mothers | Fathers | Mothers | Fathers | |||||
| Cases N=1643 |
Controls N=29 835 |
Cases N=1736 |
Controls N=32 846 |
Cases N=905 |
Controls N=16 744 |
Cases N=956 |
Controls N=18 401 |
|
| N (%) | N (%) | N (%) | N (%) | N (%) | N (%) | N (%) | N (%) | |
| Child’s sex | ||||||||
| Male | 901 (54.8) | 16 608 (55.7) | 957 (55.1) | 18 153 (55.3) | 483 (53.4) | 8834 (52.8) | 507 (53.0) | 9735 (52.9) |
| Female | 742 (45.2) | 13 227 (44.3) | 779 (44.9) | 14 693 (44.7) | 422 (46.6) | 7910 (47.2) | 449 (47.0) | 8666 (47.1) |
| Birth order | ||||||||
| First | 787 (47.9) | 14 056 (47.1) | 779 (44.9) | 14 636 (44.5) | 448 (49.5) | 7910 (47.2) | 450 (47.0) | 8262 (44.9) |
| Second | 602 (36.6) | 11 044 (37.0) | 659 (38.0) | 12 498 (38.1) | 333 (36.8) | 6293 (37.6) | 356 (37.4) | 7049 (38.3) |
| Third or later | 254 (15.5) | 4735 (15.9) | 298 (17.1) | 5712 (17.4) | 124 (13.7) | 2541 (15.2) | 150 (15.7) | 3090 (16.8) |
| Family socioeconomic status | ||||||||
| Academics | 147 (8.9) | 2888 (9.7) | 147 (8.5) | 3170 (9.7) | 100 (11.0) | 1665 (9.9) | 99 (10.4) | 1768 (9.6) |
| Middle education | 225 (13.7) | 4181 (14.0) | 229 (13.2) | 4195 (12.8) | 123 (13.6) | 2515 (15.0) | 121 (12.7) | 2509 (13.6) |
| Shorter education | 209 (12.7) | 4052 (13.6) | 209 (12.1) | 4144 (12.6) | 146 (16.1) | 2590 (15.5) | 148 (15.4) | 2615 (14.2) |
| Skilled | 421 (25.6) | 7211 (24.2) | 451 (26.1) | 8221 (25.1) | 228 (25.2) | 4490 (26.8) | 251 (26.2) | 5099 (27.7) |
| Unskilled | 199 (12.1) | 3492 (11.7) | 237 (13.6) | 4219 (12.8) | 102 (11.3) | 2065 (12.3) | 120 (12.6) | 2556 (13.9) |
| Unknown | 442 (26.9) | 8011 (26.9) | 463 (26.6) | 8897 (27.0) | 206 (22.8) | 3419 (20.4) | 217 (22.7) | 3854 (20.9) |
| Parental age (years) at birth of the index child | ||||||||
| ≤25 | 385 (23.4) | 7507 (25.2) | 216 (12.4) | 4486 (13.7) | 263 (29.1) | 4619 (27.6) | 146 (15.3) | 2674 (14.5) |
| 26–28 | 391 (23.8) | 6952 (23.3) | 331 (19.1) | 6217 (18.9) | 238 (26.3) | 3993 (23.8) | 197 (20.7) | 3737 (20.3) |
| 29–33 | 550 (33.5) | 9983 (33.5) | 618 (35.6) | 11 523 (35.1) | 265 (29.3) | 5410 (32.3) | 356 (37.2) | 6563 (35.7) |
| ≥34 | 317 (19.3) | 5393 (18.1) | 571 (32.9) | 10 620 (32.3) | 139 (15.4) | 2722 (16.3) | 257 (26.8) | 5427 (29.5) |
| Child's birthplace | ||||||||
| Urban | 514 (31.3) | 9814 (32.9) | 551 (31.8) | 10 832 (33.0) | 311 (34.4) | 5388 (32.2) | 320 (33.6) | 5946 (32.3) |
| Small town | 517 (31.5) | 9259 (31.0) | 547 (31.6) | 10 542 (32.1) | 278 (30.7) | 5446 (32.5) | 300 (31.5) | 6142 (33.4) |
| Rural | 612 (37.2) | 10 762 (36.1) | 638 (36.6) | 11 472 (34.9) | 316 (34.9) | 5910 (35.3) | 336 (34.9) | 6313 (34.3) |
| Number of children | ||||||||
| 1 | 360 (21.9) | 6188 (20.7) | 185 (20.4) | 3066 (18.3) | ||||
| 2 | 832 (50.6) | 14 976 (50.2) | 448 (49.5) | 8601 (51.4) | ||||
| ≥3 | 451 (27.4) | 8671 (29.1) | 272 (30.1) | 5077 (30.3) | ||||