(P29-002-20) Effect of Vitamin D3 Supplementation on Glycated Albumin in Adults with Type 2 Diabetes

Objectives: Albumin is the most abundant protein in serum with half-life of 2-3 weeks. Several studies suggested glycated albumin (GA) may provide a more accurate measure of extracellular glycation status, compared to hemoglobin A1C. Low serum vitamin D level [25(OH)D3] has been linked to diabetes. The aim of this study was to investigate the effect of different doses of vitamin D3 supplementation for 3 and 6 months on serum glycated albumin (GA) in individuals with type 2 diabetes (T2D) and hypovitaminosis D.

Methods: In this clinical trial, we assessed the effect of daily supplementation with 4000 and 6000 IU of vitamin D3 over 6 months on GA among 68 adults with T2D and hypovitaminosis D. Measurements of variables were conducted at baseline, 3 months and 6 months. Mixed model was used to compare treatment groups. Covariates in the adjusted model included age, gender, body mass index (BMI), sun exposure, fasting plasma glucose, insulin and C-reactive protein (CRP).

Results: After testing for normal distribution of variables, 65 participants, females (n=40) and males (n=25), were included in the analysis. Mean age was 54.52 ± 7.86 years. Mean serum 25(OH)D3 at baseline, 3 months and 6 months were 22.4 ± 6.77, 40.4 ± 13.68, and 40.57 ± 14.55, respectively. Mean GA at baseline, 3 months and 6 months were 4.69 ± 1.7, 4.13 ± 1.09, and 4.42 ± 1.23, respectively. Mixed model analysis controlling for interactions between 4000 IU and 6000 IU/day doses and outcome variables showed no differences between 2 treatment groups. Unadjusted pairwise comparisons between GA were a statistically significant from baseline to 3 months (P=0.015), and from 3 months to 6 months (P=0.039), but not from baseline to 6 months (P= 0.488). After adjusting for covariates, the model remained statistically significant for baseline and 3 months (P= 0.018) but not for 3 months to 6 month (P= 0.069), nor for baseline and 6 months (P= 0.471).

Conclusions: GA may be a more sensitive biomarker for oxidative/glycemic changes in individuals with T2D  and hypovitaminosis D and daily supplementation with higher doses of vitamin D3 may have beneficial effects on their health status. Larger studies with longer durations among different racial and ethnic groups may help to confirm these findings.

Funding Sources: Funding for this research was provided through an NIH/NIDDK sponsored grant.