High-dose Vitamin D Supplementation on Type 1 Diabetes Mellitus Patients: Is there an Improvement in Glycemic Control?

Abstract

Background: Some authors evaluated the effect of VD on hyperglycemia in T1DM, but the results remain controversial. This study aims to analyze the effects of high-dose VD supplementation on T1DM patients’ glycemic levels, maintaining stable doses of insulin. Methods: Prospective, 12-week clinical trial including 67 T1DM patients, who were supplemented with high doses of cholecalciferol according to participants' VD value. Patients with VD levels below 30 ng/mL received 10,000 IU/day; those with levels between 30-60 ng/mL received 4,000 IU/day. Patients who had not achieved 25(OH)D levels > 30 ng/ml or presented insulin dose variation during the study were not analyzed. Results: Only 46 out of 67 patients accomplished the criteria at the end of the study. There was no general improvement in the glycemic control evaluated by HbA1c (9.4 ± 2.4 vs 9.4 ± 2.6, p=NS) after VD supplementation. However, a posthoc analysis, based on HbA1c variation, identified patients who had HbA1c reduced at least 0.6% (group 1, N = 13 (28%)). In addition, a correlation between 25(OH)D levels with HbA1c and total insulin dose at the end of the study was observed (r = -0.3, p<0.05; r=-0.4, p<0.05, respectively) and a regression model demonstrated that 25(OH)D was independent of BMI, duration of T1DM and final total insulin dose, being capable of determining 9.2% of HbA1c final levels (Unstandardized B coefficient = −0.033 (CI 95%: −0.064 to −0.002), r² = 0.1, p <0.05). Conclusion: Our data suggests that VD is not widely recommended for glycemic control. Nevertheless, specific patients might benefit from this approach.

Association Between 25(OH)Vitamin D, HbA1c and Albuminuria in Diabetes Mellitus: Data From a Population-Based Study (VIDAMAZON)

“…Nevertheless, it is still difficult to recommend VD supplementation to all prediabetics and diabetics patients. In fact, there is no consensus regarding the relationship between glycemic control and vitamin D supplementation, with studies pointing to opposite directions (16,17,30,31). Alaidarous et al (32), studying patients with T2DM have found that VD levels were affected by diabetes duration.…”

“…While cross-sectional studies have suggested a possible association (12,13), others have not (14,15). In addition, the attempts to supplement VD to improve glycemic control have also shown conflicting results (16,17). Furthermore, a recently published meta-analysis found that VD supplementation may prevent type 2 diabetes mellitus (T2DM), showing the importance of this subject (18).…”

The use of dietary supplements, and the association between supplemental vitamin D and glycaemic control in adult individuals with type 1 diabetes

“…Of relevance to individuals with diabetes, lower serum 25-hydroxyvitamin D concentrations have, in some studies, been associated with insulin resistance, 6 severity of diabetic ketoacidosis, 7 higher insulin requirements, 7,8 and worse glycaemic control. 7 While some vitamin D intervention studies have shown reductions in fasting blood glucose and HbA 1c concentrations, glycaemic variability, insulin need and frequency of hypoglycaemia, 9,10 a number of studies have reported no improvements in glycaemic control, [11][12][13][14][15][16] insulin sensitivity, 14 insulin requirement, 15 or βcell function. 15,17 Moreover, in one study, the reduction in HbA 1c was only reported in those with worse glycaemic control at baseline, 18 and in another study such improvements were only observed in individuals with type 2 diabetes, and not in those with type 1 diabetes.…”