Taking some heartburn medications for more than two years is linked to a higher risk of vitamin B12 deficiency in adults, a U.S. study suggests.

Left untreated, vitamin B12 deficiency can lead to dementia, neurological damage, anemia, and other complications. Knowing that stomach acid aids in vitamin B12 absorption, researchers set out to test whether suppressing the acids can lead to vitamin deficiency.

Heartburn

Acid inhibitors for heartburn and ulcers are among the most commonly used pharmaceuticals (iStock)

The drugs in question are known as proton pump inhibitors and they include such well known brands as Losec, Nexium, Prevacid and Pariet. 

Doses of more than 1.5 pills per day were more strongly associated with vitamin B12 deficiency than doses of less than 0.75 pills per day, Dr. Douglas Corley, a gastroenterologist and research scientist with the Kaiser Permanente Division of Research in Oakland, Calif. and his co-authors said in Wednesday's issue of the Journal of the American Medical Association.

"This research raises the question of whether people who are taking acid-depressing medications long term should be screened for vitamin B12 deficiency," Corley said in a release. "It's a relatively simple blood test, and vitamin supplements are an effective way of managing the vitamin deficiency, if it is found."

For the study, researchers looked at electronic health records of 25,956 adults diagnosed with vitamin B12 deficiency in Northern California between January 1997 and June 2011, and compared them with 184,199 patients without B12 deficiency during the same time period.

Among the 25,956 patients who had vitamin B12 deficiency, 12 per cent used proton pump inhibitors for at least two years, compared with 7.2 per cent of those in the control group.

At a minimum, the findings point to a population at higher risk of vitamin B12 deficiency, the researchers said.

Acid inhibitors for heartburn and ulcers are among the most commonly used pharmaceuticals in the U.S., and 14.9 million patients received prescriptions for the drugs last year, a previous study found.

The association was stronger in women, younger age groups and for the stronger proton pump inhibitors compared with another class of the medications, called histamine 2 receptor antagonists.

The association decreased when people stopped taking the heartburn medications.

The researchers cautioned the findings do not recommend against using the heartburn medications when it is clearly indicated, but that clinicians should use the lowest possible effective dose.

The study was funded by the Kaiser Permanente Community Benefit Grant. Corley has received or sought a grant from Wyeth/Pfizer.