TABLE 1.
Baseline characteristics of participants in 2 pilot clinical trials of vitamin D3 supplementation1
| Pilot 1 | Pilot 2 | |||
|---|---|---|---|---|
| Placebo | 2000 IU/d | 2000 IU/d | 4000 IU/d | |
| n | 11 | 11 | 8 | 7 |
| Age, y | 61.0 ± 13 | 60.6 ± 10 | 30.3 ± 9.5 | 40.3 ± 8.3 |
| Male sex | 7 (64) | 7 (64) | 2 (25) | 2 (29) |
| Race | ||||
| White/Caucasian | 6 (55) | 9 (82) | 7 (87) | 3 (43) |
| Black/African American | 1 (9) | 2 (18) | 1 (13) | 2 (29) |
| Asian | 2 (18) | None | None | 1 (14) |
| Hispanic/Latino | 1 (9) | None | None | 1 (14) |
| Native Hawaiian/Pacific Islander | 1 (9) | None | None | None |
| Serum 25(OH)D3, ng/mL | 20.2 ± 8.7 | 16.4 ± 7.2 | 12.5 ± 3.7 | 12.9 ± 4.6 |
| Serum vitamin D3, ng/mL | 0.42 [0.17–0.92] | 0.23 [0.13–0.50] | 0.17 [0.14–0.28] | 0.07 [0.07–0.32] |
| Serum 1,25(OH)2D3, pg/mL | 29.4 ± 15 | 32.6 ± 10 | 32.1 ± 5.8 | 35.0 ± 6.1 |
| Serum 24,25(OH)2D3, ng/mL | 2.68 ± 1.4 | 2.22 ± 1.6 | 1.01 ± 0.45 | 1.03 ± 0.72 |
| Serum PTH, pg/mL | 43.1 ± 19 | 60.4 ± 21 | 35.4 ± 10 | 51.4 ± 10 |
| BMI, kg/m2 | 35.3 ± 8.0 | 39.9 ± 8.7 | 31.8 ± 5.3 | 36.6 ± 7.6 |
| T2DM diagnosis | 11 (100) | 11 (100) | None | None |
1
Values are means ± SDs, n (%), or medians [IQRs] unless otherwise indicated. SI conversion factors: 25(OH)D3, 1 ng/mL = 2.5 nmol/L; vitamin D3, 1 ng/mL = 2.6 nmol/L; 24,25(OH)2D3, 1 ng/mL = 2.4 nmol/L; 1,25(OH)2D3, 1 pg/mL = 2.4 pmol/L. PTH, parathyroid hormone; T2DM, type 2 diabetes mellitus; 1,25(OH)2D3, 1,25-dihydroxyvitamin D3; 24,25(OH)2D3, 24,25-dihydroxyvitamin D3; 25(OH)D3, 25-hydroxyvitamin D3.