TABLE 1.
Neonatal and maternal characteristics at birth and at baseline1
| Parameters | Reference 400 IU/d (n = 41) | Trial 400 IU/d (n = 49) | Trial 1000 IU/d (n = 49) |
|---|---|---|---|
| Infants | |||
| At birth (24–36 h postpartum) | |||
| Sex | |||
| Male | 23 (56.1) | 29 (59.2) | 29 (59.2) |
| Female | 18 (43.9) | 20 (40.8) | 20 (40.8) |
| UVB period2 | |||
| Synthesizing period | 25 (61.0) | 30 (61.2) | 26 (53.1) |
| Nonsynthesizing period | 16 (39.0) | 19 (38.8) | 23 (46.9) |
| Gestational age, wk | 39.6 ± 1.0 | 39.7 ± 1.0 | 39.6 ± 1.1 |
| Weight, kg | 3.5 ± 0.3 | 3.4 ± 0.4 | 3.4 ± 0.4 |
| Weight-for-age z score | 0.3 ± 0.7 | 0.1 ± 0.8 | 0.1 ± 0.8 |
| Serum 25(OH)D, nmol/L | 68.0 ± 13.2 | 30.8 ± 9.2 | 34.4 ± 12.0 |
| At baseline (1 mo postpartum) | |||
| Skin tone3 | |||
| F I–III | 38 (92.7) | 35 (71.4) | 35 (71.4) |
| F IV–VI | 3 (7.3) | 14 (28.6) | 14 (28.6) |
| Weight, kg | 4.1 ± 0.5 | 3.9 ± 0.5 | 3.9 ± 0.5 |
| Weight-for-age z score | 0.03 ± 0.8 | −0.2 ± 0.9 | −0.1 ± 0.7 |
| Length, cm | 53.5 ± 2.0 | 52.7 ± 1.8 | 52.9 ± 2.2 |
| Length-for-age z score | 0.1 ± 1.0 | −0.2 ± 0.9 | 0.03 ± 0.9 |
| HC, cm | 36.5 ± 1.1 | 36.6 ± 1.2 | 36.1 ± 1.3 |
| HC-for-age z score | 0.1 ± 0.9 | 0.3 ± 0.9 | −0.02 ± 0.8 |
| Serum 25(OH)D, nmol/L | 69.2 ± 16.4 | 45.8 ± 14.1 | 47.6 ± 13.4 |
| Mothers | |||
| At delivery (24–36 h postpartum) | |||
| Mother's age, y | 32.3 ± 4.0 | 32.8 ± 4.3 | 31.2 ± 4.8 |
| Father's age, y | 35.0 ± 4.9 | 35.8 ± 5.4 | 33.2 ± 5.3 |
| Self-reported population group | |||
| White | 31 (75.6) | 22 (44.9) | 24 (49.0) |
| All other groups4 | 10 (24.4) | 27 (55.1) | 25 (51.0) |
| Family income, CAD | |||
| ≥70,000 | 29 (70.7) | 27 (55.1) | 22 (44.9) |
| <70,000 | 7 (17.1) | 15 (30.6) | 18 (36.7) |
| Not reported | 5 (12.2) | 7 (14.3) | 9 (18.4) |
| Education | |||
| Elementary/high school | 1 (2.4) | 8 (16.3) | 4 (8.2) |
| College/vocational school | 10 (24.4) | 8 (16.3) | 11 (22.4) |
| University | 30 (73.2) | 33 (67.4) | 34 (69.4) |
| Prepregnancy BMI, kg/m2 | 23.1 ± 2.6 | 24.6 ± 4.4 | 25.8 ± 5.9 |
| Supplement use5 | 38 (92.7) | 44 (89.8) | 46 (93.9) |
| Parity | |||
| Primiparous | 13 (31.7) | 12 (24.5) | 19 (38.8) |
| Multiparous (i.e., ≥2) | 28 (68.3) | 37 (75.5) | 30 (61.2) |
| At baseline (1 mo postpartum) | |||
| Serum 25(OH)D, nmol/L | 94.3 ± 23.3 | 51.6 ± 14.5 | 60.0 ± 22.9 |
1
Values are mean ± SD or n (%). CAD, Canadian dollar; F, Fitzpatrick; HC, head circumference; 25(OH)D, 25-hydroxyvitamin D.
2
Infants born in vitamin D–synthesizing period: 1 April–31 October or vitamin D–nonsynthesizing period: 1 November–31 March.
3
Based on Fitzpatrick descriptions (F I–III or F IV–VI).
4
Including South Asian, Chinese, black, Filipino, Latin American, Arab, Southeast Asian, West Asian, Korean, Japanese, and other.
5
Maternal multivitamin use during pregnancy (yes/no).