TABLE 1.
Selected baseline characteristics of study participants
| Variable | All (n = 218) | Vitamin D (n = 109) | Placebo (n = 109) |
| Age (y) | 59.6 ± 5.11 | 60.3 ± 5.3 | 59.0 ± 4.7 |
| Weight (kg) | 87.7 ± 16.3 | 87.4 ± 15.5 | 88.1 ± 17.1 |
| BMI (kg/m2) | 32.4 ± 5.8 | 32.3 ± 5.5 | 32.5 ± 6.1 |
| Waist circumference (cm) | 100.1 ± 12.3 | 100.0 ± 11.0 | 100.3 ± 13.5 |
| Body fat (%) | 47.4 ± 4.9 | 47.3 ± 5.2 | 47.5 ± 4.5 |
| Race-ethnicity [n (%)] | |||
| Non-Hispanic white | 188 (86.2) | 94 (86.2) | 94 (86.2) |
| Non-Hispanic black | 13 (6.0) | 7 (6.4) | 6 (5.5) |
| Hispanic | 5 (2.3) | 1 (0.9) | 4 (3.7) |
| Other2 | 12 (5.5) | 7 (6.4) | 5 (4.6) |
| College graduate [n (%)] | 161 (73.9) | 82 (75.2) | 79 (72.5) |
| Moderate to vigorous physical activity (min/wk) | 142.2 ± 143.2 | 137.9 ± 146.5 | 146.6 ± 140.4 |
| Energy intake (kcal/d)3 | 2004 ± 699.3 | 2025 ± 722 | 1982 ± 678 |
| Relative energy from fat (%) | 33.0 ± 6.2 | 33.4 ± 6.7 | 32.6 ± 5.7 |
| Relative energy from protein (%) | 17.6 ± 3.2 | 17.2 ± 2.9 | 17.9 ± 3.5 |
| Relative energy from carbohydrate (%) | 48.3 ± 7.4 | 48.5 ± 7.8 | 48.1 ± 7.1 |
| Dietary vitamin D intake (μg) | 6.6 ± 4.6 | 6.3 ± 4.0 | 6.9 ± 5.2 |
| Vitamin D supplement intake (IU) | 332.4 ± 106.2 | 262.7 ± 140.5 | 303.6 ± 125.2 |
| Total calcium intake, diet + supplement (mg) | 1120 ± 600 | 1170 ± 633 | 1071 ± 564 |
| Sun exposure (h/wk)4 | 2.4 ± 1.3 | 2.2 ± 1.3 | 2.5 ± 1.3 |
| Serum 25(OH)D5 (ng/mL) | 21.4 ± 6.1 | 21.4 ± 6.1 | 21.4 ± 6.2 |
1
Mean ± SD (all such values).
2
Includes American Indian, Asian, or unknown.
3
Values derived from a food-frequency questionnaire were truncated to <600 and >4000 kcal. Independent t tests showed no significant differences in baseline measures between groups.
4
Calculated based on average exposure between 1000 and 1600; reported separately for weekdays and weekends.
5
25(OH)D, 25-hydroxyvitamin D.