Marques FL, et al. - In this cross-sectional study, researchers assessed the link between vitamin B12 deficiency and its risk factors, as well as examined the connection between established deficiency and clinically detectable periph­eral neuropathy. Study participants included 316 patients with type 2 diabetes mellitus who were assisted at a public healthcare service, of whom 91% were on metformin treatment. In addition to an association with the use of angiotensin-converting enzyme inhibitors, the researchers noted a dose-depend­ent association between metformin use and vitamin B12 deficiency. They also observed peripheral neuropathy in 41% of patients, which was not related to vitamin B12 deficiency. Among metformin users, the prevalence of peripheral neuropathy was lower.