Vitamin B12 deficiency has been associated with significant neurological pathology, especially peripheral neuropathy. This review aims to examine the existing evidence on the effectiveness of vitamin B12 supplementation for the treatment of diabetic peripheral neuropathy. A search of PubMed and the Cochrane Central Register of Controlled Trials for all relevant randomised controlled trials was conducted in December 2014. Any type of therapy using vitamin B12 or its coenzyme forms was assessed for efficacy and safety in diabetics with peripheral neuropathy. Changes in vibration perception thresholds, neuropathic symptoms and nerve conduction velocities, as well as the adverse effects of vitamin B12 therapy, were assessed. Four studies comprising 363 patients met the inclusion criteria. This review found no evidence that the use of oral vitamin B12 supplements is associated with improvement in the clinical symptoms of diabetic neuropathy. Furthermore, the majority of studies reported no improvement in the electrophysiological markers of nerve conduction.
Diabetic Neuropathies ; complications ; drug therapy ; Dietary Supplements ; Humans ; Vitamin B 12 ; therapeutic use ; Vitamin B 12 Deficiency ; drug therapy ; etiology ; Vitamins ; therapeutic use

Megaloblastic anemia following gastrectomy is due to the total absence or inadequate secretion of intrinsic factor and is manifested by megalobastic changes in bone marrow, blood cells, and other proliferative cells. In Korea, detailed description and precise analyses of the cases of megaloblastic anemia following gastrectomy are relatively rare in contrast to the potential of its incidence from gastrectomy due to many causes or to the importance of its clinical significance. Here, we present the case of a 51-year old man who had undergone a total gastrectomy with esophagojejunostomy and incidental splenectomy due to early gastric cancer and developed megalobastic anemla 7 years after surgery. After gradual improvement of clinical and hematologic features with treatment of parenteral vltamin Bl2, he was followed-up with vitamin B12 maintenance therapy.
Anemia, Macrocytic/*etiology ; Anemia, Megaloblastic/diagnosis/*etiology ; Case Report ; Gastrectomy/*adverse effects ; Human ; Male ; Middle Age ; Vitamin B 12 Deficiency/*etiology

We evaluated the prevalence of vitamin B12 deficiency and associated factors in type 2 diabetes patients using metformin. A total of 799 type 2 diabetes patients using metformin was enrolled. Vitamin B12 and folate levels were quantified by chemiluminescent enzyme immunoassay. Vitamin B12 deficiency was defined as vitamin B12 < or = 300 pg/mL without folate deficiency (folate > 4 ng/mL). The prevalence of vitamin B12 deficiency in metformin-treated type 2 diabetes patients was 9.5% (n = 76), and the mean vitamin B12 level was 662.5 +/- 246.7 pg/mL. Vitamin B12 deficient patients had longer duration of metformin use (P < 0.001) and higher daily metformin dose (P < 0.001) than non-deficient patients. Compared with daily metformin dose of < or = 1,000 mg, the adjusted odds ratio for 1,000-2,000 mg, and > or = 2,000 mg were 2.52 (95% CI, 1.27-4.99, P = 0.008) and 3.80 (95% CI, 1.82-7.92, P < 0.001). Compared with metformin use of < 4 yr, the adjusted odds ratios for 4-10 yr, and > or = 10 yr were 4.65 (95% CI, 2.36-9.16, P < 0.001) and 9.21 (95% CI, 3.38-25.11, P < 0.001), respectively. In conclusion, our study indicates that patients with type 2 diabetes treated with metformin should be screened for vitamin B12 deficiency, especially at higher dosages (> 1,000 mg) and longer durations (> or = 4 yr) of treatment.
Aged ; Area Under Curve ; Diabetes Mellitus, Type 2/complications/diagnosis/*drug therapy ; Female ; Folic Acid/blood ; Humans ; Hypoglycemic Agents/adverse effects/*therapeutic use ; Immunoassay ; Male ; Metformin/adverse effects/*therapeutic use ; Middle Aged ; Odds Ratio ; Patients ; Prevalence ; ROC Curve ; Time Factors ; Vitamin B 12/blood ; Vitamin B 12 Deficiency/diagnosis/epidemiology/*etiology