Association between metformin and vitamin B12 deficiency in patients with type 2 diabetes: A systematic review and meta-analysis

Metformin is the most widely used oral hypoglycaemic drug, but it may lower B12 status, which could have important clinical implications. We undertook a systematic review and meta-analysis of the relationship between metformin use and vitamin B12 deficiency in persons with type 2 diabetes.Electronic database searches were undertaken (1st January 1957-1st July 2013) using the Cochrane library, Scopus, CINAHL, Grey literature databases, Pub Med...