Vitamin D and Diabetic Complications: True or False Prophet?

Abstract

Vitamin D deficiency is now recognized as a condition of increasing prevalence worldwide. Vitamin D has an established role in calcium and bone metabolism; however, more recently associations with vitamin D deficiency and risk of developing diabetes, diabetes complications, and cardiovascular disease have all been acknowledged. The vitamin D receptor is ubiquitously expressed, and experimental, in vitro, and in vivo studies strongly suggest a role in regulating the transcription of multiple genes beyond calcium homeostasis. These include antiproliferative, immunomodulatory, angiogenic, inhibition of the renin–angiotensin–aldosterone system, and neurotrophic factor expression. Observational studies report a strong association between vitamin D deficiency and cardiovascular and metabolic disorders; however, there remains a paucity of large long-term randomized clinical trials showing a benefit with treatment. An increasing body of literature suggests a possible pathogenetic role of vitamin D in the long-term complications of diabetes and vitamin D deficiency may also exacerbate symptoms of painful diabetic peripheral neuropathy. It remains unknown if supplementation of vitamin D to normal or non-deficient levels alters pathogenetic processes related to diabetic microvascular complications. With the high prevalence of vitamin D deficiency in patients with diabetes and putative mechanisms linking vitamin D deficiency to diabetic complications, there is a compelling argument for undertaking large well-designed randomized controlled trials of vitamin D supplementation.

Type 2 Diabetic Patients

“…Furthermore decrease expression of toll like receptors (2 & 4) and reactive oxygen species are other possible mechanisms. [17][18][19] Our results were consistent with two other studies, which were separately conducted in type 1 and type 2 diabetic patients. They pointed out that oral vitamin D therapy for a period of 12 weeks significantly improved symptoms of neuropathic pain in vitamin D deficient patients.…”

Untitled

“…Created on increasing data from animal and human investigations, vitamin D insufficiency is presently considered as a potential risk factor for type 2 DM [6]. Cholecalciferol is connected with pathogenesis of pancreatic в-cell dysfunction, insulin resistance and systemic inflammation [7]. It is known that these conditions are partly responsible for the development of type 2 DM.…”

Diabetes and Bone

“…2,13,14 Vitamin D deficiency appears to be of additional clinical importance. 15 The deposition of advanced glycation end-products in the bone matrix is considered to contribute to poor bone quality and thus high susceptibility to low trauma fractures. 16,17 Other data support the potential relevance of impaired osteocyte health in diabetic bone disease.…”