Reduced serum vitamin B-12 in patients taking metformin.

Josep Vidal-Alaball honorary research fellow [email protected] Christopher C Butler professor of primary care medicine, Department of Primary Care and Public Health, Heath Park, Cardiff CF14 4YS Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure. pdf (available on request from the corresponding author) and declare: (1) No financial support for the submitted work from anyone other than their employer; (2) No financial relationships with commercial entities that might have an interest in the submitted work; (3) No spouses, partners, or children with relationships with commercial entities that might have an interest in the submitted work; (4) No non-financial interests that may be relevant to the submitted work.” Provenance and peer review: Commissioned; not externally peer reviewed.