title: 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 ≤ 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 ≤ 1,000 mg, the adjusted odds ratio for 1,000-2,000 mg, and ≥ 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 ≥ 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 (≥ 4 yr) of treatment.
authors.affiliation: Division of Endocrinology & Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Sun-Hye
authors.identifier: 0000-0003-3387-3986
authors.initials: SH
authors.lastname: Ko
authors.affiliation: Division of Endocrinology & Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Sun-Hee
authors.identifier: 0000-0001-6638-1609
authors.initials: SH
authors.lastname: Ko
authors.affiliation: Division of Endocrinology & Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yu-Bae
authors.initials: YB
authors.lastname: Ahn
authors.affiliation: Division of Endocrinology & Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Ki-Ho
authors.identifier: 0000-0003-1883-7039
authors.initials: KH
authors.lastname: Song
authors.affiliation: Department of Biostatistics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Kyung-Do
authors.identifier: 0000-0002-6096-1263
authors.initials: KD
authors.lastname: Han
authors.affiliation: Department of Preventive Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea. ; Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA.
authors.forename: Yong-Moon
authors.identifier: 0000-0002-5879-6879
authors.initials: YM
authors.lastname: Park
authors.affiliation: Division of Endocrinology & Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Ko
authors.affiliation: Division of Endocrinology & Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Hye-Soo
authors.identifier: 0000-0002-2419-4669
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000368:Aged; D019540:Area Under Curve; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D005260:Female; D005492:Folic Acid / Q000097:blood; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D007118:Immunoassay; D008297:Male; D008687:Metformin / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D016017:Odds Ratio; D010361:Patients; D015995:Prevalence; D012372:ROC Curve; D013997:Time Factors; D014805:Vitamin B 12 / Q000097:blood; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin; D005492:Folic Acid; D014805:Vitamin B 12
keywords: Diabetes Mellitus; Metformin; Type 2; Vitamin B12 Deficiency