TABLE 1.
Characteristics of 1194 mother-infant pairs in Project Viva according to maternal intake of vitamin D during pregnancy1
| Quartile of vitamin D intake during pregnancy
|
P for trend2 | ||||
|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | ||
| Vitamin D intake (IU) | |||||
| Median | 356 | 513 | 603 | 724 | |
| Range | 60–445 | 446–562 | 563–658 | 659–1145 | |
| No. of subjects | 298 | 299 | 299 | 298 | |
| Maternal and family history | |||||
| Maternal age at enrollment (y) | 31.3 ± 5.73 | 32.6 ± 4.6 | 32.7 ± 4.5 | 33.5 ± 4.4 | < 0.001 |
| Prepregnancy BMI (kg/m2) | 25.7 ± 6.0 | 24.2 ± 4.9 | 24.1 ± 4.5 | 24.0 ± 4.6 | < 0.001 |
| Maternal dietary intake | |||||
| Vitamin D from foods (IU) | 164 ± 76 | 186 ± 78 | 228 ± 75 | 320 ± 95 | < 0.001 |
| Vitamin D from supplements (IU) | 163 ± 107 | 322 ± 86 | 370 ± 67 | 421 ± 86 | < 0.001 |
| Calcium intake (mg) | 1109 ± 284 | 1327 ± 301 | 1447 ± 299 | 1620 ± 335 | < 0.001 |
| Vitamin A intake (μg RE) | 1663 ± 579 | 2087 ± 577 | 2328 ± 572 | 2582 ± 692 | < 0.001 |
| Fruit and vegetables (servings/d) | 5.8 ± 2.9 | 5.9 ± 2.4 | 6.1 ± 2.5 | 6.0 ± 3.1 | 0.17 |
| Fish (servings/wk) | 1.7 ± 1.4 | 1.8 ± 1.3 | 1.9 ± 1.4 | 2.1 ± 1.7 | < 0.001 |
| College graduate (%) | 53 | 74 | 80 | 82 | < 0.001 |
| Household income >$70 000/y (%) | 55 | 66 | 68 | 71 | < 0.001 |
| Mother smoked during index pregnancy (%) | 13 | 12 | 9 | 6 | 0.001 |
| Family history | |||||
| Maternal asthma (%) | 19 | 16 | 21 | 13 | 0.09 |
| Maternal eczema (%) | 15 | 21 | 18 | 24 | 0.02 |
| Maternal asthma or eczema (%) | 30 | 30 | 32 | 31 | 0.62 |
| Paternal asthma (%) | 18 | 17 | 9 | 14 | 0.05 |
| Paternal eczema (%) | 15 | 17 | 13 | 14 | 0.38 |
| Paternal asthma or eczema (%) | 30 | 28 | 21 | 25 | 0.05 |
| Child and home environment | |||||
| Maternal LMP during winter (%) | 18 | 21 | 24 | 23 | 0.08 |
| Boy (%) | 50 | 52 | 48 | 53 | 0.68 |
| White (%) | 63 | 78 | 78 | 79 | < 0.001 |
| Birth weight (kg) | 3.48 ± 0.52 | 3.53 ± 0.55 | 3.53 ± 0.48 | 3.51 ± 0.51 | 0.54 |
| Gestational age at birth (wk) | 39.5 ± 1.5 | 39.6 ± 1.5 | 39.8 ± 1.4 | 39.6 ± 1.4 | 0.31 |
| Fetal growth (birth-weight-for-GA z score) | 0.16 ± 1.0 | 0.25 ± 1.0 | 0.19 ± 0.9 | 0.20 ± 0.9 | 0.72 |
| Dietary intake during childhood | |||||
| Breastfeeding for ≥9 mo (%) | 32 | 37 | 41 | 49 | < 0.001 |
| Duration of breastfeeding (mo) | 5.7 ± 4.5 | 6.0 ± 4.6 | 6.7 ± 4.5 | 7.3 ± 4.4 | < 0.001 |
| Vitamin supplement use in first 6 mo (%) | 10 | 15 | 18 | 20 | < 0.001 |
| Vitamin D intake from foods at age 2 y (IU) | 225 ± 108 | 248 ± 103 | 251 ± 85 | 267 ± 106 | < 0.001 |
| Passive smoke exposure at home (%) | 14 | 6 | 5 | 6 | < 0.001 |
| Number of children aged <12 y at home | 1.8 ± 0.8 | 1.7 ± 0.8 | 1.6 ± 0.7 | 1.6 ± 0.7 | < 0.001 |
| Furry pet at home (%) | 40 | 42 | 42 | 41 | 0.80 |
| Home cockroach exposure (%) | 4 | 4 | 4 | 3 | 0.50 |
| Moisture or mildew in home (%) | 28 | 28 | 27 | 30 | 0.82 |
1
RE, retinol equivalents; LMP, last menstrual period; GA, gestational age.
2
Based on Mantel-Haenszel chi-square test for categorical variables and linear regression for continuous variables.
3
x̄ ± SD (all such values).