Table 2.
Characteristics of the study cohorts - potential confounding factors
| Greenland | Kharkiv | Warsaw | ||
|---|---|---|---|---|
| Age [years] | 26.8 (± 6.1) | 6.1 (± 25) | 25 (± 4.8) | |
| Pre-pregnancy BMI [kg/m2] | 24.5 (± 4.3) | 4.3 (± 21.6) | 21.6 (± 3.2) | |
| Education | left before 15 or 15-17 | 227 (41.5%) | 156 (27%) | - |
| left at age 18 | 46 (8.4%) | 144 (25%) | 44 (22.2%) | |
| continued above age 18 | 211 (38.6%) | 207 (35.9%) | 150 (75.8%) | |
| missing | 63 (11.5%) | 70 (12.1%) | 4 (2.0%) | |
| Marital status | married | 114 (20.8%) | 322 (55.8%) | 160 (80.8%) |
| living as married | 323 (59.0%) | 195 (33.8%) | 32 (16.2%) | |
| living alone | 55 (10.1%) | 51 (8.8%) | 6 (3.0%) | |
| missing | 55 (10.1%) | 9 (1.6%) | 0 (0.0%) | |
| Smoking1 | never smoker | 64 (11.7%) | 368 (63.8%) | 129 (65.2%) |
| smoker | 65 (11.9%) | 78 (13.5%) | 32 (16.2%) | |
| ex-smoker | 418 (76.4%) | 131 (22.7%) | 37 (18.7%) | |
| Exposure to other people's cigarette smoke1 | no | 146 (26.7%) | 110 (19.1%) | 71 (35.9%) |
| yes | 390 (71.3%) | 455 (78.9%) | 126 (63.6%) | |
| missing | 11 (2.0%) | 12 (2.1%) | 1 (0.5%) | |
| Alcohol drinks1 |
less than 14/week | 519 (94.9%) | 576 (99.8%) | 197 (99.5%) |
| 14 and more/week | 28 (5.1%) | 1 (0.2%) | 1 (0.5%) | |
| Occupational exposure1 |
no | 539 (98.5%) | 497 (86.1%) | 172 (86.9%) |
| yes | 8 (1.5%) | 80 (13.9%) | 26 (13.1%) | |
| Previous pregnancies | 0 | 63 (11.5%) | 320 (55.5%) | 148 (74.7%) |
| 1 | 83 (15.2%) | 127 (22.0%) | 34 (17.2%) | |
| 2+ | 395 (72.2%) | 107 (18.5%) | 9 (4.5%) | |
| missing | 6 (1.1%) | 23 (4.0%) | 7 (3.5%) | |
| Newborn sex | Boy | 295 (53.9%) | 300 (52.0%) | 96 (48.5%) |
| Girl | 292 (53.4%) | 277 (48.0%) | 102 (51.5%) | |
1during the period of attempt to conceive