Is Metformin-Induced Vitamin B12 Deficiency Responsible for Cognitive Decline in Type 2 Diabetes?

INTRODUCTION: Diabetes mellitus has its deleterious effects on various aspects of cognition such as memory function, executive function, and information-processing speed. The present study aims to assess cognition in diabetes patients and also tries to find its association with Vitamin B12 deficiency induced by metformin. MATERIALS AND METHODS: Thirty diabetics taking metformin and thirty nondiabetic controls were enrolled. Event-related potentials (ERPs) and serum Vitamin B12 levels were evaluated in them. RESULTS: Vitamin B12 levels were found to be deficient, and latencies of waves P200 and P300 were prolonged in the diabetics as compared to the controls. The dose and duration of metformin had no association with the ERPs. CONCLUSIONS: Although the Vitamin B12 levels were deficient in diabetics on metformin, this is not the reason behind the cognitive impairment found in them.