Table 1. Associations of demographic, pregnancy, and birth characteristics with hepatoblastoma adjusted for birth weight, birth year, and sex — Minnesota, 1982–2004.
| Subcohort (n=7788) | Cases (n=36) | |||
|---|---|---|---|---|
| Characteristic | N (%) | N (%) | HRa | 95% CI |
| Birth characteristics | ||||
| Birth weight (g) | ||||
| >2000 | 7606 (98.0) | 28 (77.8) | 1 | |
| 1000–1999 | 124 (1.6) | 4 (11.1) | 9.15 | 3.09–27.1 |
| <1000 | 31 (0.4) | 4 (11.1) | 25.6 | 7.70–85.0 |
| Sex | ||||
| Female | 3778 (48.5) | 11 (30.6) | 1 | |
| Male | 4010 (51.5) | 25 (69.4) | 2.03 | 0.98–4.19 |
| Gestational age (weeks)b | ||||
| ⩾37 | 6888 (91.6) | 25 (69.4) | 1 | |
| <37 | 631 (8.4) | 11 (30.6) | 1.70 | 0.56–5.13 |
| Size for gestational age | ||||
| Small | 252 (3.4) | 0 (0.0) | — | |
| Average | 5427 (72.4) | 29 (80.6) | — | |
| Large | 1821 (24.3) | 7 (19.4) | — | |
| Multiple birth | ||||
| No | 7592 (97.5) | 34 (94.4) | — | |
| Yes | 196 (2.5) | 2 (5.6) | — | |
| Apgar score (1 min) | ||||
| >7 | 5725 (76.6) | 19 (52.8) | 1 | |
| ⩽7 | 1746 (23.4) | 17 (47.2) | 1.99 | 0.95–4.16 |
| Apgar score (5 min) | ||||
| >7 | 7192 (96.4) | 29 (80.6) | 1 | |
| <7 | 265 (3.6) | 7 (19.4) | 2.24 | 0.70–7.11 |
| Assisted ventilationc | ||||
| No | 4549 (98.3) | 25 (86.2) | 1 | |
| Yes | 79 (1.7) | 4 (13.8) | 2.00 | 0.49–8.19 |
| Congenital abnormality | ||||
| No | 7676 (98.6) | 31 (86.1) | 1 | |
| Yes | 112 (1.4) | 5 (13.9) | 5.87 | 1.88–18.3 |
| Index pregnancy history | ||||
| Adequacy of prenatal care | ||||
| Adequate | 4530 (67.9) | 24 (75.0) | 1 | |
| Intermediate | 1488 (22.3) | 4 (12.5) | 0.61 | 0.21–1.78 |
| Inadequate | 658 (9.9) | 4 (12.5) | 1.11 | 0.36–3.43 |
| Weight gain (pounds)c | ||||
| ⩽24 | 1029 (26.7) | 7 (25.9) | 1 | |
| 25–30 | 1295 (33.6) | 10 (37.0) | 1.36 | 0.48–3.83 |
| >30 | 1526 (39.6) | 10 (37.0) | 1.40 | 0.48–4.07 |
| Intrauterine procedures | ||||
| No | 7271 (97.4) | 32 (88.9) | 1 | |
| Yes | 193 (2.6) | 4 (11.1) | 2.39 | 0.68–8.41 |
| Induction of laborc | ||||
| No | 3439 (71.6) | 20 (66.7) | 1 | |
| Yes | 1361 (28.4) | 10 (33.3) | 1.32 | 0.60–2.93 |
| Type of delivery | ||||
| Vaginal | 6162 (82.0) | 26 (72.2) | 1 | |
| Caesarean section | 1355 (18.0) | 10 (27.8) | 1.26 | 0.58–2.77 |
| Maternal reproductive history | ||||
| Prior live births | ||||
| 0 | 3062 (39.9) | 16 (44.4) | 1 | |
| 1–2 | 3799 (49.5) | 11 (30.6) | 0.62 | 0.28–1.35 |
| ⩾3 | 808 (10.5) | 9 (25.0) | 2.07 | 0.87–4.92 |
| Interval since last live birth (years) | ||||
| No prior birth | 3062 (40.1) | 16 (44.4) | — | |
| ⩽3 | 2966 (38.9) | 18 (50.0) | — | |
| >3 | 1600 (21.0) | 2 (5.6) | — | |
| Prior fetal losses | ||||
| None | 5919 (77.5) | 30 (83.3) | 1 | |
| Any | 1717 (22.5) | 6 (16.7) | 0.60 | 0.24–1.49 |
| Parental demographics | ||||
| Mother's age (years) | ||||
| <25 | 2358 (30.3) | 11 (30.6) | 1.27 | 0.53–3.08 |
| 25–29 | 2708 (34.8) | 10 (27.8) | 1 | |
| ⩾30 | 2722 (35.0) | 15 (41.7) | 1.31 | 0.57–3.01 |
| Father's age (years) | ||||
| <30 | 3347 (47.5) | 11 (33.3) | 1 | |
| ⩾30 | 3693 (52.5) | 22 (66.7) | 1.55 | 0.74–3.25 |
| Mother's race | ||||
| White | 7010 (90.9) | 30 (83.3) | 1 | |
| Non-white | 700 (9.1) | 6 (16.7) | 1.56 | 0.63–3.89 |
| Mother's ethnicityc | ||||
| Non-Hispanic | 4475 (96.5) | 26 (86.7) | 1 | |
| Hispanic | 160 (3.5) | 4 (13.3) | 2.96 | 0.88–10.0 |
| Mother's birthplace | ||||
| United States | 7297 (93.8) | 28 (77.8) | 1 | |
| Elsewhere | 485 (6.2) | 8 (22.2) | 3.55 | 1.51–8.32 |
| Father's race | ||||
| White | 6381 (92.5) | 28 (87.5) | 1 | |
| Nonwhite | 521 (7.5) | 4 (12.5) | 1.44 | 0.49–4.29 |
| Father's ethnicityc | ||||
| Non-Hispanic | 3996 (97.0) | 24 (85.7) | 1 | |
| Hispanic | 125 (3.0) | 4 (14.3) | 4.18 | 1.22–14.3 |
| Mother's education (years) | ||||
| <12 | 782 (10.6) | 8 (22.9) | 1.60 | 0.64–4.02 |
| 12 | 2706 (36.8) | 14 (40.0) | 1 | |
| >12 | 3867 (52.6) | 13 (37.1) | 0.61 | 0.28–1.32 |
| Father's education (years) | ||||
| ⩽12 | 2840 (44.2) | 13 (43.3) | 1 | |
| >12 | 3587 (55.8) | 17 (56.7) | 1.03 | 0.49–2.16 |
Abbreviations: CI=confidence interval; HR= Hazard ratios; LNMP=last normal menstrual period
a
Hazard ratios adjusted for birth weight, birth year, and sex.
b
Imputed gestational age based on LNMP when available and physician's estimate when LNMP was missing.
c
Collected in birth years 1989–2004.