From: Parental and infant characteristics and childhood leukemia in Minnesota
 | Sub-cohort | ALL | AML | ||||
---|---|---|---|---|---|---|---|
 | No. (%) | No. (%) | HR | 95% CI | No. (%) | HR | 95% CI |
Plurality | Â | Â | Â | Â | Â | Â | Â |
   1 | 8526 (97) | 547 (98) | ref. | 86 (99) | ND** | ||
   ≥2 | 224 (3) | 12 (2) | 0.82 | 0.46–1.48 | 1 (1) |  |  |
   missing | 1 (0) | 1 (0) |  |  | 0 (0) |  |  |
Previous live births | Â | Â | Â | Â | Â | Â | Â |
   0 | 3449 (40) | 202 (37) | ref. | 29 (33) | ref. |  | |
   1–2 | 4251 (49) | 286 (52) | 1.15 | 0.95–1.38 | 49 (56) | 1.39 | 0.87–2.20 |
   ≥3 | 903 (11) | 61 (11) | 1.14 | 0.85–1.54 | 9 (10) | 1.20 | 0.56–2.54 |
   missing | 147 (2) | 11 (2) |  |  | 0 (0) |  |  |
Prior fetal loss | Â | Â | Â | Â | Â | Â | Â |
   any | 1866 (22) | 134 (25) | 1.14 | 0.94–1.41 | 19 (22) | 1.00 | 0.59–1.68 |
   none | 6711 (78) | 407 (75) | ref. | 68 (78) |  | ref. | |
   missing | 173 (3) | 19 (3) |  |  | 0 (0) |  |  |
Last fetal death interval | Â | Â | Â | Â | Â | Â | Â |
   no fetal deaths | 6564 (80) | 404 (77) | ref. | 67 (82) |  | ref. | |
   <3 years | 891 (11) | 73 (14) | 1.30 | 1.00–1.69 | 8 (10) | 0.92 | 0.44–1.93 |
   ≥3 years | 722 (9) | 51 (10) | 1.13 | 0.83–1.53 | 7 (8) | 0.96 | 0.44–2.11 |
   missing | 573 (7) | 32 (6) |  |  | 5 (6) |  |  |
Last live birth interval | Â | Â | Â | Â | Â | Â | Â |
   no live births | 3449 (40) | 202 (37) | ref. | 29 (35) | ref. |  | |
   <3 years | 3333 (39) | 200 (36) | 1.02 | 0.84–1.25 | 34 (40) | 1.22 | 0.74–2.02 |
   ≥3 years | 1786 (21) | 148 (27) | 1.40 | 1.12–1.75 | 21 (25) | 1.40 | 0.79–2.47 |
   missing | 182 (2) | 10 (2) |  |  | 3 (3) |  |  |
Maternal diabetes* | Â | Â | Â | Â | Â | Â | Â |
   any | 110 (3) | 8 (3) | 1.00 | 0.48–2.08 | 0 (0) |  | ND |
   none | 3194 (97) | 229 (97) | ref. | 33 (100) |  |  | |
   missing | 215 (6) | 9 (4) |  |  |  |  |  |
Gestational anemia | Â | Â | Â | Â | Â | Â | Â |
   yes | 80 (2) | 8 (3) | 1.52 | 0.72–3.19 | 1 (2) |  | ND |
   no | 4612 (98) | 305 (97) | ref. | 42 (98) |  |  | |
   missing | 291 (6) | 23 (7) |  |  | 4 (9) |  |  |
Maternal hypertension | Â | Â | Â | Â | Â | Â | Â |
   any | 337 (4) | 28 (6) | 1.32 | 0.88–1.96 | 5 (6) | 1.40 | 0.56–3.49 |
   none | 7678 (96) | 481 (94) | ref. | 76 (94) |  | ref. | |
   missing | 735 (8) | 51 (9) |  |  | 6 (7) |  |  |
Intrauterine procedures | Â | Â | Â | Â | Â | Â | Â |
   yes | 203 (2) | 13 (2) | 1.01 | 0.57–1.78 | 2 (2) | 0.97 | 0.24–4.00 |
   no | 8181 (98) | 515 (92) | ref. | 81 (98) |  | ref. | |
   missing | 366 (4) | 32 (6) |  |  | 4 (5) |  |  |
Maternal weight gain + | Â | Â | Â | Â | Â | Â | Â |
   < 30 lbs | 2323 (60) | 148 (56) | ref. | 12 (36) |  | ref. | |
   ≥ 30 lbs | 1526 (40) | 115 (44) | 1.17 | 0.91–1.52 | 21 (64) | 2.59 | 1.27–5.31 |
   missing | 1134 (23) | 73 (22) |  |  | 14 (30) |  |  |
Prenatal care index †|  |  |  |  |  |  |  |
   less than adequate | 2300 (33) | 146 (31) | 0.95 | 0.77–1.16 | 16 (22) | 0.57 | 0.33–1.00 |
   adequate | 4747 (67) | 323 (69) | ref. | 57 (78) |  | ref. | |
   missing | 1151 (14) | 72 (13) |  |  | 11 (13) |  |  |
Induction of labor ‡ |  |  |  |  |  |  |  |
   yes | 1432 (27) | 92 (27) | 0.97 | 0.75–1.24 | 18 (39) | 1.67 | 0.91–3.04 |
   no | 3878 (73) | 244 (73) | ref. | 28 (61) |  | ref. | |
   missing | 225 (4) | 19 (5) |  |  | 4 (8) |  |  |
Type of delivery | Â | Â | Â | Â | Â | Â | Â |
   vaginal | 6952 82) | 432 (82) | ref. | 73 (86) |  | ref. | |
   caesarean section | 1485 (18) | 98 (18) | 1.03 | 0.82–1.30 | 12 (14) | 0.75 | 0.41–1.39 |
   missing | 313 (4) | 30 (5) |  |  | 2 (2) |  |  |