Table 1.
Clinical characteristics of the study population (n = 15,651)
| Total sample | Vitamin D SUFFa |
Vitamin D INSUFF/DEFb |
P | |
|---|---|---|---|---|
| Maternal characteristics | ||||
| Age, mean (SD), y | 30.36 (3.68) | 30.62 (3.69) | 30.24(3.72) | < 0.0001 |
| Prepregnancy BMI, mean (SD), kg/m2 | 21.98 (2.63) | 20.71 (2.58) | 21.09(2.73) | < 0.0001 |
| BMI groups | < 0.0001 | |||
| BMI, 18.5–23.9 kg/m2, n (%) | 11,827 (75.56) | 3852 (75.90) | 7975(75.41) | |
| BMI, < 18.5 kg/m2, n (%) | 2074 (13.26) | 774 (15.25) | 1300 (12.29) | |
| BMI, ≥ 24 kg/m2, n (%) | 1750 (11.18) | 449 (8.85) | 1301 (12.30) | |
| Gestational age, mean (SD), weeks | 38.9 (1.39) | 38.8 (1.32) | 38.9 (1.43) | < 0.0001 |
| Parity, n (%) | < 0.0001 | |||
| Nulliparous | 11,902 (76.04) | 3654 (72.00) | 8248 (77.98) | |
| Multiparous | 3749 (23.95) | 1421 (28.00) | 2328 (21.02) | |
| C-section, n (%) | 6641 (42.43) | 2163 (42.62) | 4478 (42.34) | 0.74 |
| GDM, n (%) | 1613 (10.31) | 559 (11.01) | 1054 (9.96) | 0.05 |
| PIH, n (%) | 379 (2.42) | 109 (2.15) | 270 (2.55) | 0.12 |
| ICP, n (%) | 111 (0.71) | 33 (0.65) | 78 (0.74) | 0.54 |
| Season at VD testing | < 0.0001 | |||
| Spring (March–May) | 3986 (25.47) | 1199 (23.63) | 2787 (2635) | |
| Summer (June–August) | 3669 (23.44) | 1492 (29.39) | 2177 (20.59) | |
| Autumn (September–November) | 3959 (25.30) | 1403 (27.65) | 2556 (24.17) | |
| Winter (December–February) | 4037 (25.79) | 981 (19.33) | 3056 (28.89) | |
| Neonatal characteristics | ||||
| Male sex, n (%) | 8096 (51.73) | 2675 (52.71) | 5421 (51.26) | 0.09 |
| Birthweight, mean (SD), g | 3341.7 (438.10) | 3335.7 (433.35) | 3344.5 (440.28) | 0.24 |
| Preterm birth (< 37 wk), n (%) | 825 (5.27) | 272 (5.35) | 553 (5.23) | 0.73 |
| SGA, n (%) | 570 (3.64) | 172 (3.39) | 398 (3.76) | 0.24 |
| Low birthweight (< 2500 g), n (%) | 456 (2.91) | 144 (2.84) | 312 (2.95) | 0.69 |
| LGA, n (%) | 2166 (13.84) | 667 (13.14) | 1499 (14.17) | 0.08 |
| High birthweight (≥ 4000 g), n (%) | 930 (5.94) | 282 (5.55) | 648 (6.13) | 0.16 |
BMI body mass index (calculated as weight in kilograms divided by height in meters squared), GDM gestational diabetes mellitus, ICP intrahepatic cholestasis of pregnancy, LGA large for gestational age, PIH pregnancy-induced hypertension, SGA small for gestational age
aSUFF (sufficient), 25(OH)D in serum ≥ 50.00 nmol/L
bINSUFF/DEF (insufficient or deficient), 25(OH)D in serum < 50.00 nmol/L