This study was designed to determine whether elderly residents of long term care facilitated who had been taking proton pump inhibitors (PPI) for more than 12 months were more likely to have vitamin B12 deficiency than residents not taking PPI, and whether cyanocobalamin nasal spray improved these subjects' vitamin B12 status.

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.

Inclusion Criteria:

• age 60-89 years
• PPI use for >12 months (PPI group)
• no PPI use for 30 days prior to arm 1
• long term care resident

Exclusion Criteria:

• pernicious anemia
• severe megaloblastic anemia
• free-living
• serum creatinine > 1.8 mg/dL