Introduction: Vitamin D deficiency is involved in the pathogenesis of insulin resistance, which is the main factor in the development of type 2 diabetes. In Poland, a high percentage of people with vitamin D deficiency is observed, as well as incidences of type 2 diabetes. In 2013, recommendations regarding vitamin D supplementation for Central Europe inhabitants were published, which recommend the use of vitamin D preparations for obese people with a dose of 600-4000 IU / per Day
Purpose of the work: Evaluation of the prevalence of vitamin D deficiency in obese patients with chronically decompensated type 2 diabetes mellitus and appropriate supplementation in accordance with given recommendations.
Material and metod: Evaluation of laboratory tests and applied pharmacotherapy in 40 patients with chronically decompensated type 2 diabetes, aged from 38 to 89 years old.
Results: In the experimental group the average concentration of 25 (OH) D3 was 20.3 ng / ml ± 11.7. Supplementation of vitamin D preparations was used by 15% of patients. Only 22.5% of patients had correct concentrations of 25 (OH) D3, but only one person used vitamin D supplements in this group.
Conclusions: One in five obese patients with type 2 diabetes have normal levels of vitamin D. Among obese diabetics nearly 90% of patients do not apply the recommendations for vitamin D supplementation. Knowledge about the benefits of vitamin D supplementation should be widely propagated among diabetologists and general practitioners.

vitamin D; type 2 diabetes mellitus; insulin resistance; carbohydrate management

Holick MF (2007).. Vitamin D deficiency. N Engl J Med. 357: 266-81.

Adams JS, Hewison M. (2010). Update in vitamin D. J Clin Endocrinol Metab 95: 471–478.

Rosner CJ. (2011). Vitamin D insufficiency. N Engl J Med 364: 248–254

Muscogiuri G. (2018). Vitamin D: past, present and future perspectives in the prevention of chronic diseases. Eur J Clin Nutr. 72(9):1221-1225.

Nitsa A, Toutouza M, Machairas N, Mariolis A, Philippou A, Koutsilieris M. (2018). Vitamin D in Cardiovascular Disease. In Vivo. 32(5):977-981

Maestro B, Campión J, Dávila N, Calle C. (200). Stimulation by 1,25-dihydroxyvitamin D3 of insulin receptor expression and insulin responsiveness for glucose transport in U-937 human promonocytic cells. Endocr J. 47(4):383-91.

Płudowski P, Karczmarewicz E, Bayer M, et al. (2013). Practical guidelines for the supplementation of vitamin D and the treatment of deficits in Central Europe - recommended vitamin D intakes in the general population and groups at risk of vitamin D deficiency. Endokrynol Pol. 64(4):319-27.

Markovic D, Hills CE et al. (2004). Expression of 25-hydroxyvitamin D3-1 alpha-hydroxylase in pancreatic islets. J Steroid Biochem Mol Biol 121: 89–90.

Pittas AG, Lau J, Hu FB, Dawson-Hughes B. (2007). The role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis. J Clin Endocrinol Metab; 92: 2017-29.

Zeitz U, Weber K, Soegiarto DW. Et al. (2003). Impaired insulin secretory capacity in mice lacking a functional vitamin D receptor. FASEB J 17: 509-11.

Bland R, Markovic D, Hills CE. Et al. (2004). Expression of 25-hydroxyvitamin D3-1alpha-hydroxylase in pancreatic islets. J Steroid Biochem Mol Biol 89-90: 121-5.

Maestro B, Dávila N, Carranza MC et al. (2003). Identification of a vitamin D response element in the human insulin receptor gene promoter. J Steroid Biochem Mol Biol 84: 223-30.

Chiu KC, Chu A, Go VL et al. (2004). Hypovitaminosis D is associated with insulin resistance and a cell dysfunction. Am J ClinNutr 79: 820-5.

Berridge MJ. (2017). Vitamin D deficiency and diabetes. Biochem J. 24;474(8):1321-1332.

Pittas AG, Lau J, Hu FB et al. (2007). The role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis. J Clin Endocrinol Metab 92: 2017-29.

Mathieu C. (2015). Vitamin D and diabetes: Where do we stand? Diabetes Res Clin Pract. 108(2):201-9.

Botella-Carretero JI, Alvarez-Blasco F, Villafruela JJ et al. (2007). Vitamin D deficiency is associated with the metabolic syndrome in morbid obesity. ClinNutr 26: 573-80.

Liyanage GC, Lekamwasam S, Weerarathna TP, Liyanage CE. (2017). Effects of high-dose parenteral vitamin D therapy on lipid profile and blood pressure in patients with diabetic nephropathy: A randomized double-blind clinical trial. Diabetes Metab Syndr. 11 Suppl 2:S767-S770.

Usluogullari CA, Balkan F, Caner S, Ucler R, Kaya C, Ersoy R, Cakir B.(2015). The relationship between microvascular complications and vitamin D deficiency in type 2 diabetes mellitus. BMC Endocr Disord. 15:33.

Herrmann M, Sullivan DR, Veillard AS, McCorquodale T. et al. (2015). Serum 25-hydroxyvitamin D: a predictor of macrovascular and microvascular complications in patients with type 2 diabetes. Diabetes Care 38(3):521-8.

Cade C, Norman AW. (1986). Vitamin D3 improves impaired glucose tolerance and insulin secretion in the vitamin D-deficient rat in vivo. Endocrinology 119: 84-90.

Clark SA, Stumpf WE, Sar M. (1981). Effect of 1,25-dihydroxyvitamin D3 on insulin secretion. Diabetes 30: 382-6.

Jehle S, Lardi A, Felix B, Hulter HN, Stettler C, Krapf R.(2014). Effect of large doses of parenteral vitamin D on glycaemic control and calcium/phosphate metabolism in patients with stable type 2 diabetes mellitus: a randomised, placebo-controlled, prospective pilot study. Swiss Med Wkly 144:w13942.