One of the major complications of diabetes is vascular disease. Vascular complications include, heart attack, stroke, retinopathy (eye), nephropathy (kidney), neuropathy (numbness and tingling in extremities), and amputation. Research appearing in Diabetes Care (2015 Mar;38(3):521-8. doi: 10.2337/dc14-0180. Epub 2014 Dec 18) looked at the relationship between low serum 25-hydroxyvitamin D and vascular complications in diabetics.
The subjects of the observational study were 9,795 participants aged 50–75 years with type 2 diabetes (diagnosed according to World Health Organization criteria). None of the subjects were taking lipid-modifying therapy at study entry. Half of the subjects were found to have low serum vitamin D (defined as 49 nmol/L or lower). Those with low serum vitamin D had a higher overall incidence of macrovascular and microvascular events than those with levels greater than 50 nmol/L. The authors concluded that low vitamin D levels were associated with an increased risk of vascular complications.