A study of the effects of large dose of parenteral vitamin D (D3) on insulin resistance in type 2 DM patients
Keywords:Fasting blood sugar, Fasting insulin levels, Homeostatic model for assessment of insulin resistance, Glycosylated hemoglobin, Type 2 diabetes mellitus
Background: Over the past decade, vitamin D is more known as a hormone because of its extra - skeletal outcomes in various disease conditions, including diabetes. Most cells, including the pancreatic β-cells, contain the vitamin D receptor and they also have the capability to produce the biologically active 1,25-dihydroxyvitamin D [1,25(OH)2D3] which allows intracrine and paracrine functions. In vitro studies have shown that the active vitamin D metabolite 1,25(OH)2D stimulated insulin release by the pancreatic β-cells. Vitamin D is known to have immune modulatory and anti-inflammatory effects and reduces peripheral insulin resistance by altering low-grade chronic inflammation. This study was done to assess whether supplementation of vitamin D in type 2 diabetes mellitus (T2DM) patients with Vitamin D deficiency has any favourable effect on insulin resistance.
Methods: It was a short term interventional study conducted at ASCOMS hospital Jammu including a total of 50 vitamin D deficient [25(OH) D <50 nmol/l] T2DM patients with an in-adequate glycemic control (HbA1c > 7.0%). All the 50 study participants completed the study and there were no changes either in anti-hyperglycemic drugs (including insulin) or antihypertensive drugs being used. After supplementation with a single high dose (600000 IU) of parenteral vitamin D3 changes in HOMA-IR (Homeostasis model assessment insulin resistance) were seen on follow up at 3 months.
Results: Vitamin D3 supplementation improved insulin sensitivity, HOMA-IR decreased from 4.05±1.42 to 3.93±1.28 (p =0.011). It decreased equally in males (3.85±1.43 to 3.76±1.30) (p value=0.023) and females (4.24±1.42 to 4.10±1.27) (p value=0.021). HOMA-IR showed negative association with Vitamin D levels both at baseline and after 3 months of follow up.
Conclusions: This improvement in insulin sensitivity is evidenced in our study by decrease in fasting insulin levels (FIL) and improvement in fasting blood sugars (FBS). It is due to both direct and indirect effects of Vitamin D3 on both insulin sensitivity and secretion.
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