TABLE 3.
Effects of cholecalciferol on vitamin D metabolites1
| CaDDM |
DDM2 |
||||
| Placebo (n = 45) | 2000 IU/d cholecalciferol (n = 46) | Placebo (n = 59) | 4000 IU/d cholecalciferol (n = 58) | P value2 | |
| Total 25(OH)D, ng/mL | |||||
| Baseline | 24.8 ± 7.23 | 24.4 ± 7.7 | 27.8 ± 12.1 | 26.2 ± 10.5 | |
| Week 16 | 18.1 ± 7 | 30.7 ± 8.1 | 27.7 ± 11.5 | 49.1 ± 12.1 | |
| Change from baseline | −6.8 ± 5.6 | 6.3 ± 9.4 | −0.3 ± 6.7 | 22.7 ± 11.8 | |
| Unadjusted difference from placebo | 13.1 (9.8, 16.4)4 | 23 (19.4, 26.6) | |||
| Adjusted difference from placebo5 | 12.9 (10.2, 15.6) | 23 (19.6, 26.4) | <0.001 | ||
| P value6 | <0.001 | <0.001 | |||
| Measured free 25(OH)D, pg/mL | |||||
| Baseline | 5.25 ± 1.59 | 4.82 ± 1.57 | 6.45 ± 3.07 | 5.79 ± 2.02 | |
| Week 16 | 4.54 ± 1.64 | 7.63 ± 1.79 | 6.17 ± 2.54 | 11.71 ± 3.17 | |
| Change from baseline | −0.79 ± 1.07 | 2.83 ± 1.78 | −0.4 ± 1.95 | 5.86 ± 3.06 | |
| Unadjusted difference from placebo | 3.62 (2.99, 4.25) | 6.26 (5.29, 7.24) | |||
| Adjusted difference from placebo5 | 3.48 (2.9, 4.06) | 6.04 (5.14, 6.93) | <0.001 | ||
| P value6 | <0.001 | <0.001 | |||
| Measured free total 25(OH)D, % | |||||
| Baseline | 0.021 ± 0.004 | 0.021 ± 0.006 | 0.024 ± 0.006 | 0.023 ± 0.006 | |
| Week 16 | 0.026 ± 0.008 | 0.026 ± 0.006 | 0.023 ± 0.004 | 0.024 ± 0.005 | |
| Change from baseline | 0.005 ± 0.007 | 0.005 ± 0.006 | −0.001 ± 0.006 | 0 ± 0.007 | |
| Unadjusted difference from placebo | 0.001 (−0.002, 0.003) | 0.002 (−0.001, 0.004) | |||
| Adjusted difference from placebo5 | 0 (−0.002, 0.003) | 0.001 (0, 0.003) | NS | ||
| P value6 | NS | NS | |||
| Intact PTH, pg/mL | |||||
| Baseline | 61.5 ± 24.8 | 66.7 ± 27.1 | 57.8 ± 24.9 | 53 ± 20.9 | |
| Week 16 | 62.1 ± 22.7 | 59 ± 23.6 | 56.9 ± 22.6 | 47.2 ± 18.3 | |
| Change from baseline | 1.5 ± 20.8 | −8.1 ± 19.7 | −2.1 ± 15.1 | −5.1 ± 16.7 | |
| Unadjusted difference from placebo | −9.7 (−18.3, −1.1) | −3 (−9.0, 3.1) | |||
| Adjusted difference from placebo5 | −7.2 (−14.9, 0.6) | −4.4 (−9.8, 1.1) | NS | ||
| P value6 | 0.068 | NS | |||
Participants without postbaseline values (4 in the CaDDM trial and 9 in the DDM2) were excluded from the analyses. In the CaDDM trial, 5 additional participants did not have serum albumin measured; therefore, free 25(OH)D could not be calculated. CaDDM, Calcium and Vitamin D for Diabetes Mellitus; DDM2, Vitamin D for Established Type 2 Diabetes; PTH, parathyroid hormone; 25(OH)D, 25-hydroxyvitamin D.
Based on 2-sample z tests for the difference in adjusted mean differences between trials.
Mean ± SD (all such values).
Mean; 95% CI in parentheses (all such values).
Results are from linear regression models adjusted for age, sex, race, BMI, season of blood draw, and baseline value of the outcome variable.
Based on the adjusted difference in change from baseline between active intervention (each vitamin D dose) and matching placebo.