TABLE 2.
Baseline maternal characteristics between racial/ethnic groups1
| Maternal baseline characteristic (n = 301) | African Americans (n = 80) | Hispanics (n = 129) | Caucasians (n = 92) | P |
| BMI, kg/m2 | 31.7 ± 7.42,H,C | 26.3 ± 6.0 | 26.3 ± 5.7 | <0.001 |
| Obesity (BMI ≥30), n (%) | 46 (57.5)H,C | 25 (19.4) | 18 (19.6) | <0.001 |
| Age, y | 26.3 ± 4.8C | 25.7 ± 4.6C | 31.6 ± 5.4 | <0.001 |
| Serum 25(OH)D, nmol/L | 40.5 ± 19.0H,C | 59.4 ± 19.7C | 74.9 ± 20.6 | <0.001 |
| Vitamin D inadequacy,3 n (%) | 62 (77.5)H,C | 40 (31.0)C | 7 (7.6) | <0.001 |
| Calcium intake, mg/d | 1035 ± 687 | 1178 ± 591C | 925 ± 409 | 0.005 |
| Physical activity, h/d | 2.7 ± 3.2H | 1.2 ± 1.5 | 2.0 ± 3.2 | 0.001 |
| Season at study entry, n (%) | 0.223 | |||
| April through September | 38 (47.5) | 72 (55.8) | 41 (44.6) | |
| October through March | 42 (52.5) | 57 (44.2) | 51 (55.4) | |
| Compliance,4 n (%) | 29 (36.3)H,C | 73 (56.6) | 63 (68.5) | <0.001 |
| Gestational visit, wk | 16.1 ± 1.4H | 15.6 ± 1.1C | 16.2 ± 1.2 | <0.001 |
| Postpartum visit, wk | 3.8 ± 2.6H,C | 2.1 ± 1.1C | 2.9 ± 2.1 | <0.001 |
There were significant differences between racial/ethnic groups in baseline BMI, obesity, age, serum 25(OH)D, vitamin D inadequacy, calcium intake, physical activity, compliance rate, and the timing of gestational and postpartum visits. Overall comparisons between racial/ethnic groups were based on a Kruskal-Wallis rank-sum test for continuous variables (means ± SDs) and Fisher’s exact test for categorical variables [n (%)]. Superscript H or superscript C indicates a significant difference from Hispanics or Caucasians, respectively. Tukey’s test was used to adjust for multiple comparisons between racial/ethnic groups. 25(OH)D, 25-hydroxyvitamin D.
Mean ± SD (all such values).
Baseline 25(OH)D concentration <50 nmol/L (<20 ng/mL).
Taking ≥75% of vitamin D pills during the course of study.