Vitamin B12 in metformin-treated diabetic patients: a cross-sectional study in Brazil *

SummaryObjectiveThe objective of this study was to evaluate the presence of vitamin B12 deficiency and the factors associated with serum vitamin B12 levels in a sample of metformin- treated Brazilian diabetic patients.MethodCross-sectional study.Results144 patients were included. Serum vitamin B12 levels were low (< 125 pmol/L) in 10 patients (6.9%) and possibly low (125 - 250 pmol/L) in 53 patients (36.8%). Serum vitamin B12 levels were negatively associated with age (B = −3.17; β= −0.171; p = 0.037) and duration of metformin use (B= −33.36; β= −0.161; p = 0.048), and positively associated with the estimated intake of vitamin B12 (B= 67.96; β= 0.249; p = 0.002).ConclusionThe present findings suggest a high prevalence of vitamin B12 deficiency in metformin-treated diabetic patients. Older patients, patients in long term treatment with metformin and low vitamin B12 intake are probably more prone to this deficiency.