Long-term Use of Proton Pump Inhibitors May Cause Vitamin B12 Deficiency in the Institutionalized Elderly

Subjects had serum creatinine \<1.8 mg/dL, no diagnosis of severe megaloblastic or pernicious anemia, and had not been taking vitamin B12 supplements. At baseline, serum vitamin B12 and methylmalonic acid (MMA) concentrations of 34 subjects from the PPI group were compared with those of the non-PPI group. The PPI group (n=13) was treated with cyanocobalamin nasal spray for eight weeks, and post-treatment vitamin B12 and MMA concentrations were compared with baseline concentrations.