Table 1 Sociodemographic, lifestyle, and clincial characteristics of the 462 mother-neonate pairs and by tertiles of placental iodine concentration
Characteristics | Total (n = 462) | Tertile 1 (n = 154) | Tertile 2 (n = 154) | Tertile 3 (n = 154) | p value for trend |
|---|---|---|---|---|---|
Mother | |||||
Age, years | 29.5 (4.4) | 29.3 (3.9) | 29.5 (4.8) | 29.6 (4.5) | 0.75 |
Pre-pregnancy BMI, kg/m2 | 24.5 (4.7) | 24.8 (5.0) | 24.6 (4.6) | 24.2 (4.7) | 0.54 |
Gestational weight gain, kg | 13.8 (5.7) | 14.5 (5.7) | 13.9 (5.6) | 13.0 (5.9) | 0.07 |
Hypertension | 0.35 | ||||
Yes | 27 (5.8%) | 6 (3.9%) | 12 (7.8%) | 9 (5.8%) | |
Smoking status | 0.08 | ||||
Never-smoker | 298 (64.5%) | 87 (56.5%) | 107 (69.5%) | 104 (67.5%) | |
Cessation before pregnancy | 122 (26.4%) | 53 (34.4%) | 32 (20.8%) | 37 (24.0%) | |
Current smoker | 42 (9.1%) | 14 (9.1%) | 15 (9.7%) | 13 (8.5%) | |
Exposure to indoor second-hand smoke | 0.32 | ||||
Yes | 26 (5.6%) | 12 (7.8%) | 6 (3.9%) | 8 (5.2%) | |
Alcohol consumptiona | 0.50 | ||||
None | 400 (86.6%) | 130 (84.4%) | 133 (86.4%) | 137 (89.0%) | |
≤2 glasses per week | 62 (13.4%) | 24 (15.6%) | 21 (13.6%) | 17 (11.0%) | |
Educationb | 0.58 | ||||
Low | 59 (12.8%) | 20 (13.0%) | 24 (15.6%) | 15 (9.7%) | |
Middle | 153 (33.1%) | 54 (35.0%) | 47 (30.5%) | 52 (33.6%) | |
High | 250 (54.1%) | 80 (52.0%) | 83 (53.9%) | 87 (56.8%) | |
Multi-vitamin use | 0.12 | ||||
Yes | 259 (56.1%) | 77 (50.0%) | 87 (56.5%) | 95 (61.7%) | |
Fish consumption | 0.63 | ||||
Never | 34 (7.4%) | 14 (9.1%) | 8 (5.2%) | 12 (7.8%) | |
Less than once per week | 205 (44.4%) | 66 (42.9%) | 74 (48.1%) | 65 (42.2%) | |
At least once per week | 223 (48.2%) | 74 (48.0%) | 72 (46.8%) | 77 (50.0%) | |
Fruit and vegetable consumption | 0.58 | ||||
Less than once per day | 55 (11.9%) | 17 (11.0%) | 16 (10.4%) | 22 (14.3%) | |
Once per day | 146 (31.6%) | 50 (32.5%) | 54 (35.1%) | 42 (27.3%) | |
More than once per day | 261 (56.5%) | 87 (56.5%) | 84 (54.6%) | 90 (58.4%) | |
Neonate | |||||
Gestational age, weeks | 39.9 (1.0) | 39.8 (1.1) | 39.8 (1.0) | 40.1 (0.9) | 0.07 |
Birth weight, g | 3458 (426) | 3472 (465) | 3426 (431) | 3476 (378) | 0.51 |
Birth length, cm | 50.3 (1.9) | 50.4 (1.9) | 50.2 (1.8) | 50.4 (1.8) | 0.75 |
Sex | 0.48 | ||||
Male | 237 (51.3%) | 77 (50.0%) | 85 (55.2%) | 75 (48.7) | |
Ethnicity | 0.78 | ||||
European | 403 (87.2%) | 135 (87.7%) | 136 (88.3%) | 132 (85.7%) | |
Parity | 0.83 | ||||
1 | 244 (52.8%) | 79 (51.3%) | 80 (52.0%) | 85 (55.2%) | |
2 | 156 (33.8%) | 51 (33.1%) | 53 (34.4%) | 52 (33.8%) | |
≥3 | 62 (13.4%) | 24 (15.6%) | 21 (13.6%) | 17 (11.0%) | |
Season at delivery | 0.04 | ||||
Winter (Dec 21 to March 20) | 105 (22.7%) | 24 (15.6%) | 42 (27.3%) | 39 (25.3%) | |
Spring (March 21 to June 20) | 111 (24.0%) | 34 (22.0%) | 44 (28.6%) | 33 (21.4%) | |
Summer (June 21 to Sept 20) | 133 (28.8%) | 48 (31.2%) | 37 (24.0%) | 48 (31.2%) | |
Autumn (Sept 21 to Dec 20) | 113 (24.5%) | 48 (31.2%) | 31 (20.1%) | 34 (22.1%) | |
Placental iodine concentration, µg/kg | 26.1 (4.3) | 21.6 (2.0) | 25.8 (1.0) | 30.8 (2.7) | - |