Table 1. Sociodemographic and Clinical Characteristics, by Self-Reported Race/Ethnicity.
Continuous and ordinal variables reported as median (range) unless otherwise noted, and compared between groups using the Wilcoxon rank-sum test. Categorical variables reported as frequency (%), and compared between groups using the chi-square test or Fisher’s exact test. P-values controlled for race and site were obtained using multivariable linear or logistic regression, when sample size permitted.
| Characteristic | Total Cohort N=257 | 2000 IU/day N=130 | 4000 IU/day N=127 | p-value | p-value controlled for race & site |
|---|---|---|---|---|---|
| Maternal age (mean ± SD) | 25.0 ± 5.1 | 24.5 ± 5.3 | 25.4 ± 5.0 | 0.076 | 0.116 |
| Gestational age at enrollment (mean ± SD) | 12.4 ± 1.8 | 12.4 ± 1.7 | 12.4 ± 2.0 | 0.48 | 0.60 |
| Planned pregnancy | 95 (37.0%) | 47 (36.2%) | 48 (37.8%) | 0.79 | 0.64 |
| Gravidity | 1 (0 – 7) | 1 (0 – 7) | 1 (0 – 7) | 0.37 | 0.29 |
| Primigravida | 97 (37.7%) | 51 (39.2%) | 46 (36.2%) | 0.62 | 0.55 |
| Parity | 1 (0 –4) | 0 (0 –4) | 1 (0 – 4) | 0.069 | 0.071 |
| BMI ≥ 30 | 70 (27.2%) | 32 (24.6%) | 38 (29.9%) | 0.34 | 0.34 |
| Race | |||||
| African-American | 124 (48.3%) | 61 (46.9%) | 63 (49.6%) | 0.56 | – |
| Caucasian | 25 (9.7%) | 12 (9.2%) | 13 (10.2%) | ||
| Hispanic | 101 (39.3%) | 55 (42.3%) | 46 (36.2%) | ||
| Other | 7 (2.7%) | 2 (1.5%) | 5 (3.9%) | ||
| Highest education achieved | |||||
| Less than high school | 72 (28.0%) | 35 (26.9%) | 37 (29.1%) | 0.85 | 0.74 |
| High school | 104 (40.5%) | 56 (43.1%) | 48 (37.8%) | ||
| Some college | 57 (22.2%) | 27 (20.8%) | 30 (23.6%) | ||
| Assoc. degree or higher | 24 (9.3%) | 12 (9.2%) | 12 (9.5%) | ||
| Employed | 116 (45.1%) | 60 (46.2%) | 56 (44.1%) | 0.74 | 0.61 |
| Season (April – September) | 163 (63.4%) | 83 (63.9%) | 80 (63.0%) | 0.89 | 0.83 |
| Insurance status | |||||
| None | 93 (36.2%) | 48 (36.9%) | 45 (35.4%) | 0.96 | 0.81 |
| Medicaid | 117 (45.5%) | 59 (45.4%) | 58 (45.7%) | ||
| Private | 47 (18.3%) | 23 (17.7%) | 24 (18.9%) | ||
| Prior obstetrical history | |||||
| Preterm birth | 12 (4.7%) | 5 (3.9%) | 7 (5.5%) | 0.57 | – |
| Preeclampsia | 11 (4.3%) | 5 (3.9%) | 6 (4.7%) | 0.77 | – |
| Gestational diabetes | 7 (2.7%) | 4 (3.1%) | 3 (2.4%) | 1.00 | – |
| Diabetes (Type I or II) | 5 (2.0%) | 2 (1.5%) | 3 (2.4%) | 0.68 | – |
| Chronic hypertension | 2 (0.8%) | 0 | 2 (1.6%) | 0.24 | – |
| Subjective health rating | 9 (3 – 10) | 9 (3 – 10) | 10 (5 – 10) | 0.29 | 0.18 |
Missing data as follows: gestational age, n=3.