Table 1.
Comparison of maternal and infant characteristics of study population (n=910) between maternal vitamin D categories
| Overall | Deficiency (<50 nmol/L) | Insufficiency (≥50 and <75 nmol/L) | Sufficiency (≥75 nmol/L) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| n=910 | n=120 | n=241 | n=549 | p-value | |||||
| Mean/N1 | SD/%2 | Mean/N1 | SD/%2 | Mean/N1 | SD/%2 | Mean/N1 | SD/%2 | ||
| Maternal characteristics | |||||||||
| Maternal vitamin D plasma conc (nmol/L) | 81.3 | 27.2 | 39.0 | 7.5 | 63.0 | 7.1 | 98.7 | 18.6 | <0.001 |
| Maternal age (years) | 30.5 | 5.1 | 29.0 | 5.3 | 29.7 | 5.0 | 31.3 | 5.0 | <0.001 |
| Maternal BMI at 26 weeks 3(kg/m2) | 26.1 | 4.3 | 26.8 | 4.5 | 26.4 | 4.7 | 25.8 | 4.1 | 0.033 |
| Total maternal energy intake (kcal) | 2029 | 1288 | 2161 | 1893 | 1976 | 1180 | 2022 | 1165 | 0.432 |
| Ethnicity | <0.001 | ||||||||
| Chinese | 509 | 55.9 | 27 | 22.5 | 96 | 39.8 | 386 | 70.3 | |
| Malay | 232 | 25.5 | 56 | 46.7 | 87 | 36.1 | 89 | 16.2 | |
| Indian | 169 | 18.6 | 37 | 30.8 | 58 | 24.1 | 74 | 13.5 | |
| Education3 | 0.003 | ||||||||
| Primary and Secondary | 275 | 30.2 | 44 | 36.7 | 64 | 26.6 | 167 | 30.4 | |
| Post-Secondary | 322 | 35.4 | 42 | 35.0 | 107 | 44.4 | 173 | 31.5 | |
| University | 313 | 34.4 | 34 | 28.3 | 70 | 29.0 | 209 | 38.1 | |
| Smoked regularly during pregnancy3 | 0.287 | ||||||||
| No | 886 | 97.4 | 116 | 96.7 | 238 | 98.8 | 532 | 96.9 | |
| Yes | 24 | 2.6 | 4 | 3.3 | 3 | 1.2 | 17 | 3.1 | |
| Vitamin D supplements during pregnancy4 | |||||||||
| No | 146 | 16 | 35 | 36.1 | 41 | 19.4 | 70 | 13.7 | 0.001 |
| Yes | 673 | 74 | 62 | 63.9 | 170 | 80.6 | 441 | 86.3 | |
| Gestational age during vitamin D measurement | 0.545 | ||||||||
| 5(Median ± IQR) | 26.8 | 26.4-27.6 | 27.0 | 26.4-27.7 | 26.8 | 26.4-27.6 | 26.9 | 26.4-27.6 | |
| Infant characteristics | |||||||||
| Birth weight (g) | 3105.0 | 452.6 | 3143.0 | 414.8 | 3116.8 | 482.4 | 3091.5 | 447.2 | 0.474 |
| Birth length (cm) | 48.7 | 2.3 | 49.0 | 2.1 | 48.8 | 2.3 | 48.6 | 2.3 | 0.155 |
| Birth Order | 0.543 | ||||||||
| First Child | 396 | 43.5 | 47 | 39.2 | 109 | 45.2 | 240 | 43.7 | |
| Not First Child | 514 | 56.5 | 73 | 60.8 | 132 | 54.8 | 309 | 56.3 | |
| Infant sex | 0.221 | ||||||||
| Female | 436 | 47.9 | 56 | 46.7 | 127 | 52.7 | 253 | 46.1 | |
| Male | 474 | 52.1 | 64 | 53.3 | 114 | 47.3 | 296 | 53.9 | |
| SGA | 0.789 | ||||||||
| No | 827 | 90.9 | 110 | 91.7 | 221 | 91.7 | 496 | 90.3 | |
| Yes | 83 | 9.1 | 10 | 8.3 | 20 | 8.3 | 53 | 9.7 | |
| Pre-term | 0.919 | ||||||||
| Female | 840 | 92.3 | 111 | 92.5 | 221 | 91.7 | 508 | 92.5 | |
| Male | 70 | 7.7 | 9 | 7.5 | 20 | 8.3 | 41 | 7.5 | |
1
reflects mean of continuous variables or frequency for categorical variables
2
reflects standard deviation of continuous variables or percentages of categorical variables
3
Missing values imputed for co-variates include: Education (12 imputed as Post-Secondary); Smoked regularly before pregnancy (3 imputed as No); Maternal BMI (16 imputed as median=25.36).
4
n=91 had missing data
5
n=8 had missing data