Effect of Vitamin D Supplementation on Blood Pressure and HbA1c Levels in Patients With T2D

Inclusion criteria * Men and women, ages ≥18 years * Official diagnostic criteria for type 2 diabetes fulfilled in patients on any type of oral or parenteral glucose-lowering treatment * Independent living at home * On stable regimen of BP meds (if any) with BP well controlled and/or K supplement (if any) for 2 months and which is deemed unlikely to change during the study * Stable glucose control for 2 months by any approved method including insulin Exclusion criteria * Patients with type 1 diabetes (or insulin-requiring diabetes of unclear type) * Patients on hemodialysis, with hyperparathyroidism or active cancer disease * Patients with known metabolic bone disease * Laboratory evidence of kidney (eGFR \< 60 ml/min) or liver disease * Dietary calcium intake exceeding 1500mg/d (as estimated by dietary history) * 25(OH) vitamin D levels at baseline \> 70 nmol/L * Calciuria (\> 8 mmol/24 hours as measured by 24 hour urine collections) * Hypo- and hypercalcemias and hypo- and hyperphosphatemias of any cause * Medications that affect vitamin D metabolism (e.g. antiepileptic drugs, calcimimetics, 1-34 PTH (Forsteo) vitamin D therapy over and above 400U daily 6 months prior to enrollment and during the study) * Foreseeable need for adaptation of either glucose- or blood pressure lowering during the next 6 months as decided by the family physician or the treating diabetologist - see above * History of binge eating or wt gain or loss exceeding 6 kg in past 18 months * Patients on any type of inhibitors of plasma coagulation (i.e. coumarine, heparins)