Stomach acid drugs may increase vitamin B12 deficiency risk

By Andrew M. Seaman

NEW YORK (Reuters Health) - People with vitamin B12 deficiency in a recent study were more likely to be taking proton-pump inhibitors (PPIs) and histamine 2 receptor antagonists (H2RAs), compared to those without B12 deficiency.

"This doesn't mean people should stop their medications," said senior author Dr. Douglas Corley from the Kaiser Permanente Division of Research in Oakland, California.

"It does raise the question that people who are taking these medications should have their B12 levels checked," he added.

Without enough B12, people become tired, weak, constipated and anemic, according to the U.S. National Institutes of Health. Ultimately, deficiency can lead to nerve damage and dementia.

The problem is that the body absorbs B12 with the help of stomach acid. The drugs, therefore, could "theoretically increase the population's risk of vitamin B12 deficiency," the researchers write in the Journal of the American Medical Association (JAMA).

For the new study, the researchers compared the medical records of nearly 26,000 Northern California residents who were diagnosed with a vitamin B12 deficiency between 1997 and 2011, and nearly 185,000 people with healthy B12 levels.

Among those who were vitamin B12 deficient, 12% had been on PPIs for at least two years and about 4% were on H2RAs for an equally long period.

By comparison, among people without a diagnosis of B12 deficiency, 7% had been on PPIs for two or more years and 3% were on H2RAs long-term.

Not only were PPIs and H2RAs tied to an increased risk of vitamin B12 deficiency, but higher doses were more strongly associated with deficiency than weaker ones, the researchers found.

Those findings, Corley said, suggests that people should use the drugs for as short a time as possible, and take the lowest dose that's still effective.

While the study can't prove that PPIs or H2RAs caused vitamin B12 deficiency, this isn't the first study to link anti-acid drugs to complications.

Previous research has tied PPIs to the diarrhea-causing bacteria Clostridium difficile.

"I think the study is interesting because we're becoming more and more aware that these drugs are being too widely prescribed," Dr. Peter Green said.

Green, who was not involved with the new study, is a professor of medicine and director of the Celiac Disease Center at Columbia University Medical Center in New York.

"I think it's just another little piece of evidence that physicians should take notice of to get patients off them," Green said.

"It is a cause for concern, but it's not an emergency for the average person," Corley said. "People shouldn't stop their medication based on this study alone."

SOURCE: http://bit.ly/1e3Oj56

JAMA 2013.

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