TABLE 1.

Incidence of Vitamin B12 Deficiency Among Individuals Managed With Metformin

StudySample Size (n)Individuals With B12 Deficiency (n)Individuals With B12 Deficiency (%)
Tomkin et al., 1971 (28)714*5.6
Adams et al., 1983 (29)33
Hermann et al., 2004 (30)531936
Pflipsen et al., 2009 (31)1954423
Qureshi et al., 2001 (32)702333
Calvo Romero and Ramiro Lozano, 2012 (33)8178.6
Sato et al., 2013 (34)62813
  • * Twenty-one individuals (30%) were identified as having B12 malabsorption.

  • Twelve individuals (36%) were identified as having B12 malabsorption.

  • Individuals identified as being deficient had ≥1 abnormal B12 marker (e.g., subnormal/reduced cobalamin, reduced holotranscobalamin, elevated homocysteine, and elevated methylmalonic acid)