Table 1.
Characteristics of the cohorts and their participants
| Characteristics | ALSPAC | CPP | DNBCa | JPS (Israel)b |
MoBaa | TIHS | Pooled | |
|---|---|---|---|---|---|---|---|---|
| (UK) | (USA) | (Denmark) | Prenatal | Postnatal | (Norway) | (Australia) | ||
| Recruitment years | 1991-92 | 1959-65 | 1996-2002 | 1965-68 | 1974-76 | 1999-2009 | 1987-95 | 1959-2009 |
| Sample size | ||||||||
| Original full cohort | 14 049 | 53 738 | 94 690 | 11 467 | 16 912 | 111 399 | 10 624 | 312 879 |
| Analytical sample in current study | 13 664 | 50 342 | 9362a | 10 919 | 16 279 | 10 579a | 9362 | 120 507 |
| Years of follow-up, median (range) | 15.0 (0.01-15.0) | 7.8 (0.01-8.0) | 14.3 (0.01-15.0) | 15.0 (0.2-15.0) | 15.0 (0.3-15.0) | 12.5 (0.04-15.0) | 15.0 (0.02-15.0) | 13.6 (0.01-15.0) |
| Number of cases | ||||||||
| Any cancer | 22 | 49 | 190a | 27 | 27 | 217a | 24 | 556 |
| Any leukaemia | 3 | 15 | 61a | 4 | 9 | 71a | 4 | 167 |
| Acute lymphoblastic leukaemia | 3 | 11 | 44a | 3 | 9 | 56a | 3 | 129 |
| Acute myeloid leukaemia | 0 | 2 | 14a | 1 | 0 | 15a | 1 | 33 |
| Maternal age (years), mean ± SD | 28.0 ± 5.0 | 24.1 ± 5.9 | 30.5 ± 4.3 | 27.5 ± 5.9 | 27.4 ± 5.3 | 30.2 ± 4.6 | 23.6 ± 4.4 | 26.3 ± 5.9 |
| Education ≥12 years, n (%) | 4286 (35.3) | 20 767 (41.5) | 4388 (65.5) | 2607 (24.3) | 8898 (55.7) | 6297 (63.0) | 1690 (18.1) | 48 933 (42.5) |
| Smoking during pregnancy, n (%) | 3561 (29.6) | 23 269 (46.5) | 2365 (25.7) | 1029 (9.5) | 2218 (13.8) | 2370 (23.6) | 5023 (53.7) | 39 835 (33.9) |
| Pre-pregnancy BMI (kg/m2) mean ± SD | 22.9 ± 3.8 | 22.7 ± 4.3 | 23.6 ± 4.4 | – | 22.1 ± 3.1 | 24.0 ± 4.2 | 23.2 ± 4.8 | 22.9 ± 4.1 |
| Maternal diabetes, n (%) | 497 (4.1)c | 391 (0.8) | 172 (1.8) | 30 (0.3) | 130 (0.8) | 145 (1.4) | – | 1365 (1.25) |
| Parity, primipara, n (%) | 5640 (45.3) | 15 329 (30.5) | 4157 (47.1) | 3106 (28.5) | 4916 (30.3) | 4700 (44.4) | 4387 (46.9) | 42 235 (35.6) |
| Sex of child, male, n (%) | 7052 (51.6) | 25 461 (50.7) | 4774 (51.0) | 5590 (51.2) | 8470 (52.0) | 5321 (50.3) | 6673 (71.3)d | 63 341 (52.6) |
| Gestational age at birth (weeks) median (25th, 75th) | 40 (39, 41) | 40 (38, 41) | 40 (39, 41) | 40 (39, 41) | 40 (39, 41) | 40 (39, 41) | 40 (38, 40) | 40 (39, 41) |
| Birthweight (grams), mean ± SD | 3410 ± 551 | 3177 ± 531 | 3587 ± 563 | 3280 ± 493 | 3253 ± 509 | 3604 ± 561 | 3195 ± 751 | 3294 ± 573 |
| Caesarean section, n (%) | 1393 (10.5) | 2440 (4.9) | 1486 (15.9) | 372 (3.4) | 1039 (6.4) | 1477 (14.0) | 1764 (18.9) | 9971 (8.3) |
ALSPAC, Avon Longitudinal Study of Parents and Children; BMI, body mass index; CPP, Collaborative Perinatal Project; DNBC, Danish National Birth Cohort; JPS, Jerusalem Perinatal Study; MoBa, Norwegian Mother and Child Cohort Study; SD, standard deviation; TIHS, Tasmanian Infant Health Study.
a
DNBC and MoBa provide data on a random 10% sample of the cohort and all cancer cases.
b
JPS collected data on maternal infection in two subsets (prenatal and postnatal interviews).
c
Including glycosuria.
d
High percentage of boys was due to the study design focused on children at highest risk for sudden infant death syndrome; -, data not collected.