Table.
Effect of vitamin D3 supplementation on PTH (pg/mL) and serum 25(OH)D level (ng/mL) during the treatment phase (Baseline to 3 months)a
| Vitamin D3 Dose (IU/day) |
|||||||
|---|---|---|---|---|---|---|---|
| Placebo | 1000 | 2000 | 4000 | 3 months change per 1000 IU/day of vitamin D3b | P-value | ||
| N at baseline | 61 | 65 | 61 | 63 | |||
| 25(OH)D, ng/mL, mean (SD) | |||||||
| Baseline | 16.1 (9.3) | 17.7 (9.1) | 16.3 (9.0) | 18.1 (9.1) | |||
| 3 months | 13.6 (7.7) | 27.9 (9.3) | 36.4 (11.2) | 47.5 (10.1) | |||
| 25(OH)D differencec | −1.9 (5.3) | 10.2 (9.9) | 19.9 (11.2) | 29.7 (11.3) | 7.7 [6.8, 8.6] | <0.0001 | |
| Total PTH, pg/mL, mean (SD) | |||||||
| Baseline | 39.6 (14.8) | 41.4 (17.9) | 42.4 (21.0) | 43.5 (17.2) | |||
| 3 months | 44.2 (18.3) | 39.2 (14.5) | 35.6 (16.2) | 35.3 (15.1) | |||
| PTH differenced | 3.8 (16.3) | −4.0 (16.4) | −7.4 (14.0) | −8.2 (12.5) | −2.7 [−4.0, −1.4] | <0.0001 | |
| Stratified analysis | |||||||
| N at baseline | |||||||
| Obese | 31 | 36 | 33 | 41 | |||
| Non-obese | 30 | 29 | 28 | 22 | |||
| 25(OH)D, ng/mL, mean (SD) | |||||||
| Baseline | |||||||
| Obese | 15.5 (8.6) | 17.8 (8.3) | 15.0 (9.1) | 18.5 (9.2) | |||
| Non-obese | 16.7 (10.0) | 17.6 (10.1) | 17.8 (8.7) | 17.4 (9.3) | |||
| 3 months | |||||||
| Obese | 12.8 (7.0) | 28.2 (6.1) | 35.2 (8.1) | 45.0 (10.0) | |||
| Non-obese | 14.5 (8.5) | 27.6 (11.7) | 37.8 (14.1) | 52.4 (8.6) | |||
| 25(OH)D differencec | |||||||
| Obese | −1.8 (3.5) | 10.6 (9.5) | 20.2 (9.5) | 27.2 (10.4) | 6.8 [5.8, 7.9] | <0.0001 | |
| Non-obese | −2.1 (6.8) | 9.8 (10.4) | 19.5 (13.0) | 34.6 (11.5) | 9.1 [7.6, 10.6] | <0.0001 | |
| Total PTH, pg/mL, mean (SD) | |||||||
| Baseline | |||||||
| Obese | 43.1 (16.6) | 41.6 (19.6) | 49.0 (26.6) | 47.9 (18.0) | |||
| Non-obese | 36.1 (12.1) | 41.2 (15.9) | 34.6 (9.2) | 35.0 (11.7) | |||
| 3 months | |||||||
| Obese | 48.1 (19.9) | 38.9 (9.4) | 38.5 (19.8) | 38.9 (16.5) | |||
| Non-obese | 39.8 (15.5) | 39.4 (18.5) | 32.1 (9.7) | 28.1 (8.1) | |||
| PTH differenced | |||||||
| Obese | 4.3 (18.2) | −6.7 (18.2) | −11.3 (15.8) | −9.2 (13.7) | −2.8 [−4.7, −0.9] | 0.0045 | |
| Non-obese | 3.1 (14.2) | −1.1 (14.1) | −2.8 (9.9) | −6.0 (9.6) | −2.2 [−4.0, −0.4] | 0.016 | |
a
PTH, Parathyroid hormone; 25(OH)D, 25(OH)vitamin D; mean (SD), mean (Standard Deviation); IU, international unit; BMI, body mass index, kg/m2. Non-obese (BMI < 30) and obese (BMI ≥ 30). The numbers do not always sum to group totals due to missing information for some variables.
b
Month 3 – Month 0 change in PTH per 1000 IU/day of vitamin D3 supplementation, Mean [95% confidence interval]. Month 3 – Month 0 change in 25(OH)D per 1000 IU/day of vitamin D3 supplementation, Mean [95% confidence interval]
c
Month 3 – Month 0 difference in 25(OH)D
d
Month 3 – Month 0 difference in PTH