|
Birth year adjusted analyses of maternal reproductive characteristics, pregnancy history, and labor and delivery variables and childhood leukemia. |
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| Sub-cohort |
ALL |
AML |
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|
|
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| No. (%) |
No. (%) |
HR |
95% CI |
No. (%) |
HR |
95% CI |
|
|
|
|||||||
| Plurality |
|||||||
| 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 |
|||||||
| 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 |
|||||||
| 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 |
|||||||
| 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 |
|||||||
| 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) |
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| Maternal diabetes* |
|||||||
| 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 |
|||||||
| 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 |
|||||||
| 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 |
|||||||
| 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+ |
|||||||
| < 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 |
|||||||
| 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) |
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|
*collected 1992–2004. +collected 1989–2004. †collected 1980–2004. ‡collected 1976–1979, 1989–2004. **ND = not determined | |||||||
Johnson et al. BMC Pediatrics 2008 8:7 doi:10.1186/1471-2431-8-7 |
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