Estimation of Vitamin B12 and Vitamin D Levels in Patients of Type-2 Diabetes Mellitus on Metformin Therapy

Estimation of vitamin B12 and vitamin D levels in patients of type-2 diabetes mellitus on metformin therapy Mahaboob Fayaz S1, Ravikumar Y. S2, Manthappa M3, Mahesh MG4, Aditya Nadella5, Sai Vivek V6.1, 5, 6Junior resident, 2Professor, 3Associate professor, 4Assistant professor. Department of Medicine, JSS Medical College, JSS University, Mysore, Karnataka state, India. Introduction Metformin is one of the first drug of choice in type-2 diabetes patients. However, long term use of metformin can lead to deficiency of vitamin B12 levels due to malabsorption. In addition, type-2 diabetes can be influenced in many ways by vitamin D deficiency. Here, we sought to estimate serum vitamin B12 and vitamin D levels in type-2 diabetes patients who were on metformin therapy. Materials and methods This was a case control study. A total of 60 patients were included for the study.30 patients were on Metformin (CASES) and the other 30 were on other anti-diabetic drugs (CONTROLS). Serum vitamin B12 and vitamin D levels were measured by radioimmunoassay method. Results This study clearly showed decreased vitamin B12 levels associated with metformin therapy. However, vitamin D deficiency was found among all the cases irrespective of metformin therapy. Conclusion Type 2 diabetics on long term metformin therapy can develop vitamin B12 deficiency. Low levels of vitamin D was found in all type 2 diabetics, and was not specific for the type of anti-diabetic agent used. This could be probably due to lower levels of vitamin D in Indians and diabetics at large. Hence vitamin B12 supplementation is of benefit in type 2 diabetics on metformin, and vitamin D supplementation is needed in all Indian diabetics.