Endocrine Abstracts

Vitamin B12 or cobalamin is mainly found in animal origin food products. The frequency of vitamin B12 deficiency varies between 3 and 40% in different populations. Metformin is the first-choice therapy for type 2 diabetics having some side effects, one of them being vitamin B12 malabsorption. The study aimed to evaluate serum levels of vitamin B12 in diabetic and non-diabetic patients with cobalamin deficiency.

Methods: Medical records of subjects having a vitamin B12 level <180 pg/ml were screened, consecutive 98 subjects (75 females and 23 males with a mean age of 51.3±15.9 years) were included in the retrospective study. 34 had the diagnosis of type 2 diabetes mellitus. Mean fasting blood glucose level of the diabetics was 128.1±8.3 mg/dl and mean HbA1c was 6.3±0.2%. Thirty DM patients were using metformin treatment in a dosage of 2 g/day.

Results: The mean age was 59.0±10.8 years in diabetics and 47.2±16.8 years in nondiabetics. Mean BMI was 27.8±6.2 kg/m² and mean vitamin B12 level was 139.3±29.2 pg/ml for whole population. Mean vitamin B12 level was found to be low in diabetics compared to nondiabetics (131.2±30.6 and 143.5±27.7 pg/ml, respectively, P=0.05). There were accompanying illnesses other than DM in whole group. Thyroid abnormalities without autoimmunity including multinodular goiter were present in 22 patients, dyslipidemia in 16, Hashimoto thyroiditis in 16, hypertension in 10, hirsutism in 5, hyperprolactinemia in 5, gastric problems in four, chronic kidney disease in three, panhypopituitarism in three, osteoporosis in two, heart failure in two, parathyroid adenoma in two, stomach cancer in one and lung cancer in one patient. Among comorbidities, as being autoimmune, Hashimoto thyroiditis can be together with insufficient absorbtion of vitamin B12. In the group with DM only three had accompanying Hashimoto thyroiditis. Vitamin B12 levels of subjects with Hashimoto thyroiditis did not differ those of subjects without Hashimoto thyroiditis (142.6±32.5 vs. 138.6±28.7 pg/ml, respectively).

Conclusion: Our results demonstrated that vitamin B12 levels were similar in diabetic and non-diabetic subjects with cobalamin deficiency. All patients with or without the diagnosis of diabetes should be encouraged for sufficient vitamin B12 intake and all possible factors that lead to deficiency should be eliminated.