Association of Vitamin B12 Deficiency and Metformin Use in Patients with Type 2 Diabetes

ABSTRACT

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 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 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 or = 10 yr were 4.65 (95% CI, 2.36-9.16, P 1,000 mg) and longer durations (> or = 4 yr) of treatment.