11th December 2013 – Long-term use of commonly prescribed heartburn and ulcer medications is linked to a higher risk of vitamin B12 deficiency, according to a new study.
Vitamin B 12 deficiency is relatively common – especially among older adults – and can lead to serious medical complications if undiagnosed.
Acid inhibitors are commonly used medications in the UK. Aside from treating heartburn and ulcers, they also have an important role to play in preventing diseases such as Barrett's oesophagus and cancer of the oesophagus, which may be caused by gastric fluid damaging the lining of the gullet.
Researchers at the Kaiser Permanente Division of Research in the US looked at two types of medication: proton pump inhibitors (PPIs) and histamine 2 receptor antagonists (H2 blockers), which both reduce the amount of acid made by the stomach.
They found that patients who used these medications for 2 years or more had an increased risk of vitamin B12 deficiency.
The authors, writing in the Journal of the American Medical Association, say that, as gastric acid is required to separate vitamin B12 from certain proteins in the stomach, supressing the acid can lead to the vitamin being absorbed less effectively.
To reach their findings, the researchers identified 25,956 patients in California who had been newly diagnosed as vitamin B 12 deficient and 184,199 patients from the same area without B 12 deficiency. They then compared members of both groups to check the extent of their exposure to PPIs and H2 blockers.
Among patients with a new diagnosis of vitamin B12 deficiency, 12% had been prescribed at least two years of PPIs and 4.2% had taken H2 blockers for 2 or more years.
Among patients in the other group who were not deficient in vitamin B12, 7.2% had been dispensed 2 years or more of PPIs and 3.2% had been given at least 2 years of H2 blockers.
Co-author Dr Douglas Corley, a gastroenterologist and research scientist with the Kaiser Permanente, says in a statement: "Patients who took PPI medications for more than two years had a 65% increase in their risk of B12 deficiency."
Higher risk of vitamin B12 deficiency was associated with larger doses of medication. Doses of more than 1.5 PPI pills per day were more strongly associated with deficiency than were doses less than 0.75 pills per day.
"This research raises the question of whether people who are taking acid-depressing medications long term should be screened for vitamin B12 deficiency," Dr Corley says. "It's a relatively simple blood test, and vitaminsupplements are an effective way of managing the vitamin deficiency, if it is found."
Tim Underwood, senior lecturer and honorary consultant surgeon at the University of Southampton, tells us: "This is an interesting population based study that adds vitamin B12 deficiency to a growing list of potential complications of long term PPI use.
"However, the authors are right to point out that PPI's are safe and effective for many. Perhaps the most important issue shown in this data is the number of people taking anti-acid medication. We need greater awareness of the potential consequences of long-term heartburn if we are to turn the tide of oesophageal cancer, one of the most deadly and fastest rising cancers in the West."
'Proton Pump Inhibitor and Histamine 2 Receptor Antagonist Use and Vitamin B12 Deficiency', Dr Douglas Corley et al, Journal of the American Medical Association.
Press release, Kaiser Permanente.
Tim Underwood, senior lecturer, honorary consultant surgeon, University of Southampton.
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