Table I.
Baseline Characteristics of Study Participants
| Vitamin D | ||||
|---|---|---|---|---|
| Characteristics1 | All children N = 1,024 |
Insufficient (≤ 30) N = 361 (35%) |
Sufficient (> 30) N = 663 (65%) |
p value2,3 |
| Age (years) | 8.9 (7.2 – 10.6) | 9.3 (7.6–11.0) |
8.7 (7.0–10.4) |
.0002 |
| Female gender | 413 (40%) | 155 (43%) |
258 (39%) |
.21 |
| BMI | 17.2 (15.7 – 19.8) | 17.7 (16.2–20.8) |
17.0 (15.5–19.2) |
<.0001 |
| African-American race | 134 (13%) | 88 (24%) | 46 (7%) | <.0001 |
| Income < $30,000 | 239 (24%) | 87 (25%) | 152 (24%) | .61 |
| Budesonide group | 305 (30%) | 89 (25%) | 216 (33%) | .008 |
| Moderate severity4 | 538 (53%) | 195 (54%) |
343 (52%) |
.49 |
| Skin test positivity to any allergen |
898 (88%) | 326 (90%) | 572 (86%) | .06 |
| Total IgE, IU/mL | 437 (174 – 1216) | 468 (178–1380) |
427 (170–1175) |
.15 |
| Eosinophil count, cells/mm3 Post-bronchodilator lung function |
398 (200 – 646) | 389 (200–617) |
398 (200–676) |
.44 |
| FEV1, L5 | 1.85 (1.83 – 1.87) | 1.82 (1.78 – 1.85) |
1.87 (1.84 – 1.89) |
.009 |
| FEV1/FVC ratio | 86 (82 – 90) | 86 (81–90) |
86 (82–90) |
.79 |
| Bronchodilator response (% of FEV1) |
8% (4 – 15) | 9% (4–15) |
8% (4–15) |
.66 |
| Health–care utilization | ||||
| Hospitalizations for asthma in the year prior to randomization |
328 (32%) |
142 (39%) |
186 (28%) |
.0002 |
| Any hospitalization or ED visit over 4 years |
346 (34%) |
136 (38%) |
210 (32%) |
.05 |
1
Results expressed as median (interquartile range) for continuous variables, and number of subjects (percent of group) for categorical variables.
2
Information missing on some subjects for eosinophil count (n=14), spirometry and bronchodilator response (n=2), and BMI (n=10).
3
p values are 2-sided t-test or Wilcoxon rank sum test (depending on equality of variances) for continuous variables, and Chi square test for binary variables.
4
Only subjects with mild persistent or moderate persistent asthma were enrolled in the study.
5
FEV1 is the predicted value from regression model including age, sex, and vitamin D status (for stratified columns), for subject of mean age 9 and male sex.