Prevalence of Vitamin B12 Deficiency in Patients with type 2 Diabetes Mellitus on Metformin

Background: Type 2 diabetes mellitus (T2DM) is a common public health problem in metabolism. Metformin is the oral hypoglycemic agent used as a first line together with life style modification in type 2 diabetes patients worldwide. Continuous metformin therapy increases the risk of vitamin B12 insufficiency, and its medical consequences in T2DM patients. Objective: To detect the prevalence of serum vitamin B12 deficiency in T2DM who has been treated with metformin in Erbil Province. Patients and Methods: The study involved 200 cases (100 patients and 100 controls) that met the study's basic criteria. A completed questionnaire, and a blood test for serum vitamin B12 levels were performed. A deficiency of vitamin B12 is defined as <160 pg/mL in serum vitamin B12. Results: Deficiency of serum vitamin B12 was found in 48% of patients (n=48), while HbA1c levels had no impact on this finding. In T2DM level of serum vitamin B12 that has been on metformin at a dose of ≤ 1 gm/ day shows a significant difference with those patients with no history of metformin use. Conclusion: Low levels of serum vitamin B12  came as a result of the overdosing of metformin for long period of treatment