Table 1.
Characteristics of mothers and their children according to country
| Characteristics | Combined | Greenland | Ukraine | Poland |
|---|---|---|---|---|
| (N = 1,106) | (n = 526) | (n = 491) | (n = 89) | |
| Outcome | ||||
| DCDQ-score (points) a | 52 (40–69) | 63 (51–75) | 46 (37–55) | 64 (52–73) |
| Missing, n (%) | 298 (27) | 289 (55) | 6 (1) | 3 (3) |
| SDQ-score (points) a | 7 (2–15) | 7 (2–14) | 8 (4–14) | 8 (2–15) |
| Missing, n (%) | 7 (1) | 6 (1) | 0 (0) | 1 (1) |
| SDQ, n (%) | ||||
| Normal | 954 (86) | 455 (88) | 424 (86) | 75 (85) |
| Borderline | 82 (7) | 34 (6) | 40 (8) | 8 (9) |
| Abnormal | 63 (6) | 31 (6) | 27 (6) | 5 (6) |
| Hyperactivity, n (%) | ||||
| Normal | 967 (87) | 477 (91) | 425 (86) | 65 (73) |
| Borderline | 70 (6) | 20 (4) | 42 (9) | 8 (9) |
| Abnormal | 62 (6) | 23 (4) | 24 (5) | 15 (17) |
| Missing, n (%) | 7 (1) | 6 (1) | 0 (0) | 1 (1) |
| Maternal characteristics | ||||
| Maternal age at pregnancy, years | 26 (20–35) | 26 (20–37) | 24 (20–32) | 29 (26–34) |
| Missing, n (%) | 62 (6) | 38 (7) | 24 (5) | 0 (0) |
| Maternal pre-pregnancy BMI, kg/m2 a | 22 (19–28) | 24 (20–30) | 21 (18–26) | 21 (19–24) |
| Parity, no. (%) | ||||
| 0 | 650 (59) | 167 (33) | 399 (81) | 84 (94) |
| 1 or more | 432 (39) | 335 (67) | 92 (19) | 5 (6) |
| Missing, n (%) | 24 (2) | 24 (5) | 0 (0) | 0 (0) |
| Maternal cotinine level during pregnancy, no. (%) | ||||
| >10 ng/ml - smoker | 374 (34) | 296 (56) | 76 (15) | 2 (2) |
| ≤10 ng/ml – non-smoker | 732 (66) | 230 (44) | 415 (85) | 87 (98) |
| Maternal alcohol consumption at conception, no. (%) | ||||
| ≤7 drinks/week | 1,040 (94) | 465 (88) | 491 (100) | 84 (94) |
| >7 drinks/week | 66 (6) | 61 (12) | 0 (0) | 5 (6) |
| Missing b | 582 (500) | 261 (50) | 307 (63) | 14 (16) |
| Maternal educational level, left school at age, no. (%) | ||||
| <18 years | 356 (32) | 217 (46) | 139 (28) | 0 (0) |
| ≥18 years | 621 (56) | 249 (54) | 293 (68) | 79 (100) |
| Missing, n (%) | 129 (12) | 60 (11) | 59 (12) | 10 (11) |
| Child characteristics | ||||
| Sex, no. (%) | ||||
| Male | 595 (54) | 282 (53) | 260 (53) | 53 (60) |
| Female | 505 (45) | 241 (46) | 228 (46) | 36 (40) |
| Missing, n (%) | 6 (1) | 3 (1) | 3 (1) | 0 (0) |
| Total breastfeeding duration, no. (%) | ||||
| 0 months | 62 (6) | 17 (4) | 43 (9) | 2 (2) |
| <6 months | 302 (27) | 120 (25) | 163 (33) | 19 (22) |
| 6–12 months | 334 (30) | 124 (26) | 175 (36) | 35 (39) |
| >12 months | 354 (32) | 214 (45) | 107 (22) | 33 (37) |
| Missing, n (%) | 54 (5) | 51 (10) | 3 (1) | 0 (0) |
| Gestational age, no. (%) | ||||
| ≥37 weeks | 1,043 (95) | 499 (95) | 479 (98) | 65 (94) |
| <37 weeks | 37 (3) | 24 (5) | 9 (2) | 4 (6) |
| Missing, n (%) | 26 (2) | 3 (1) | 3 (1) | 20 (22) |
| Gestational age at blood sample, weeks a | 39 (38–41) | 25 (13–37) | 23 (9–40) | 33 (27–37) |
| Birth weight, grams a | 3,430 (2,800-4,130) | 3,600 (2,840-4,370) | 3,285 (2,800-3,800) | 3,460 (2,880-4,000) |
| Age at follow-up, years a | 7 (7–9) | 8 (7–9) | 7 (7–8) | 8 (7–8) |
| Missing, n (%) | 58 (5) | 53 (10) | 5 (1) | 0 (0) |
BMI, body mass index; DCDQ, developmental coordination disorder questionnaire; PFOA, perfluorooctanoate; PFOS, perfluorooctane sulfonate; SDQ, strength and difficulties questionnaire. All percentages are based on complete-case data. a Median (10th-90th percentile). b Missing alcohol information was set to 0 intake.