Table 5.
Therapeutic role of vitamin D in patients with type 1 diabetes mellitus: randomized controlled trials (RCT).
| Study Design | Study Groups | Supplementation Dosage * | Significant Changes in Biochemical Parameters | Clinical Findings | References |
|---|---|---|---|---|---|
| RCT, DB, PC 12 months |
N = 30 (14 + 15) Age:12(11–17.5) y Dd: 61 ± 20 d |
I: Cholecalciferol 70 IU/kg/d II: Placebo |
↑ Suppressive capacity of Tregs in suplemmented group in contrast to placebo group | Significant improvement in suppressor function of Tregs in supplemented patients | [153] |
| Prospective RCT 12 months |
N = 35 (18 + 17) Age: 38.5 ± 12.5 y Dd: 1.0 (0.1–4.0) y LADA patients |
I: Unsupplemented II: Alfacalcidiol 0.5 µg/d |
I: ↓ FCP, 22% had stable FCP II: 70% had stable or ↑ FCP |
Significant improvement in preservation of pancreatic β-cells function in supplemented patients, but only with diabetes duration ≤ 12 mo | [144] |
| RCT 12 months |
N = 67 (34 + 33) Age: 13.6 ± 7.6 y Dd: <4 weeks |
I: Calcitriol 0.25 µg/d II: Nicotinamide 25 mg/kg/d |
I: ↓ DID, but only at 3 and 6 mo In both groups no changes in FCP and HbA1C at 12 mo |
Modest effect on residual pancreatic β-cells function and only temporarily reduction of insulin dose in calcitriol- supplemented patients. | [146] |
| RCT, DB, PC 18 months |
N = 38 (19 + 19) Age: 13.5 ± 5.1 y Dd: 2.2 ± 1.2 mo |
I: Cholecalciferol 2000 IU/d II: Placebo |
↑ Chemokine ligand 2 at 12 mo ↑ SCP and Tregs % at 12 mo ↓ Progression to undetectable FCP at 18 mo |
Protective immunological effect and slowing down the decline of residual pancreatic β-cells function in supplemented patients. | [152] |
| RCT, SB, PC 6 months |
N = 54 (29 + 25) Age: 10.2 ± 2.5 y Dd: 44 ± 14 d |
I: Alfacalcidiol 0.5 µg/d II: Placebo |
↑ FCP ↓ DID Stronger response in males. |
Improvement in preservation of pancreatic β-cells function in supplemented patients with a stronger effect in males. | [145] |
| RCT, DB, PC 24 months |
N = 27 (15 + 12) Age: 18 (11–35) y Dd: <12 weeks |
I: Calcitriol 0.25 µg/d II: Placebo |
No differences in FCP, HbA1C and DID between groups. | No protective effect on pancreatic β-cells function in supplemented patients. | [154] |
| RCT, DB, PC 18 months |
N = 40 (22 + 18) Age: 31.4 ± 6.8 y Dd: 35 d |
I: Calcitriol 0.25 µg/d II: Placebo |
No differences in FCP and DID between groups. | No protective effect on pancreatic β-cells function in supplemented patients. | [155] |
* Plus insulin therapy; Dd—diabetes duration; DB—double-blinded; SB—single-blinded; PC—placebo-controlled; HbA1C—glycated hemoglobin; FCP—fasting C-peptide; SCP—stimulated C-peptid.