Are children with cystic fibrosis who are treated with a proton-pump inhibitor at risk for vitamin B₁₂ deficiency?

Background: In a recent study, the authors demonstrated the beneficial effect of proton-pump inhibitors (PPI) on fat malabsorption and bone mineral content in children with cystic fibrosis (CF). Prolonged use of PPI could result in vitamin B₁₂ deficiency as a consequence of impaired release of vitamin B₁₂ from food in a nonacid environment. The aim of this study was to evaluate the vitamin B₁₂ status of CF patients either treated with a PPI or not by measuring vitamin B₁₂ and homocysteine blood levels, the latter being a sensitive indicator of vitamin B₁₂ deficiency. Methods: The study population consisted of 20 CF patients, 11 patients treated with a PPI for at least 2 years and 9 patients not treated with a PPI, and 10 healthy, age-matched control participants. Homocysteine blood levels were measured by high-performance liquid chromatography, and vitamin B₁₂ levels were measured by a competitive protein-binding assay. Results: Vitamin B₁₂ levels were significantly higher in both CF groups compared with the control participants (PPI+, P = 0.02; PPI-, P = 0.009). There was no significant difference in vitamin B₁₂, levels between both CF groups. Homocysteine levels were normal and similar in all groups. Conclusions: Cystic fibrosis patients treated with a PPI for at least 2 years show no signs of vitamin B₁₂ deficiency.