MONDAY, May 9 (HealthDay News) -- Reinforcing U.S. health officials' concerns, new Korean research suggests that long-term use of popular heartburn drugs such as Prilosec, Prevacid and Nexium is linked to an increased risk of fractures.

Scientists conducting a meta-analysis of 11 studies published between 1997 and 2011 found that proton pump inhibitors (PPIs), which reduce stomach acid production, were associated with a 29 percent increased risk of fracture. This included a 31 percent higher risk of hip fractures and a 54 percent heightened risk of vertebral fractures.

Another class of heartburn drugs known as H2-receptor antagonists or H2 blockers -- which include brand names such as Zantac and Pepcid -- were not significantly linked to fracture risk, according to the study authors. H2 blockers, however, are less powerful than PPIs at suppressing acid production, blocking only about 70 percent rather than the estimated 98 percent that can be blocked by PPIs.

"It is difficult to say uniformly what the absolute risk is because fracture risk shows many differences according to age, sex, race and ethnicity," said study lead author Dr. Chun-Sick Eom, a clinical instructor in the Department of Family Medicine at Hallym University Hospital in Chuncheon, Korea.

"Clinicians should carefully consider their decision to prescribe PPIs for patients at elevated risk for fracture, especially women older than 65 years of age," he added. "We recommend that drug doses be chosen thoughtfully with consideration of what is necessary to achieve desired therapeutic goals."

In addition, a subset of high-quality studies -- and studies adjusting for at least five variables that could also influence fracture risk -- did show an increase in fractures in people taking H2 blockers. For this reason, the study authors also recommended further study on that topic.

The study is published in the May/June issue of the journal Annals of Family Medicine.

In May 2010, the U.S. Food and Drug Administration decided that PPIs would carry a warning on their labels about their possible fracture risk. The drugs -- which include esomeprazole (Nexium), dexlansoprazole (Dexilant), omeprazole (Prilosec, Zegerid), lansoprazole (Prevacid), pantoprazole (Protonix) and rabeprazole (Aciphex) -- are used to treat stomach and small intestine ulcers, gastro-esophageal reflux disease (GERD) and inflammation of the esophagus.

Acid suppressors are the second leading medication used worldwide, Eom said, with sales in the United States in 2005 totaling nearly $27 billion.

PPIs and H2 blockers are thought to have different effects on bone metabolism, Eom noted, accounting for their disparate fracture risks. PPIs may interfere with the digestive tract's ability to absorb calcium -- a process aided by acid -- as well as the process of new bone cell growth.

Eom acknowledged that the study was limited by lack of access to individual data on nutrients that might have affected participants' fracture risks.

An editorial accompanying the study noted that the key was to balance absolute risks and benefits -- for physicians to reduce PPI use whenever appropriate, but not to worry about using them for patients such as those with acute gastric ulcers or other potentially life-threatening conditions.

Dr. David Bernstein, chief of the division of gastroenterology at North Shore University Hospital in Manhasset, N.Y., said that while the study was observational, it should prompt physicians to question the ongoing need for patients to take acid-suppressing drugs.

"We need to look at it case by case," Bernstein said. "If someone has uncontrollable reflux and needs PPI therapy long-term, they're probably going to get it. They feel better, and it's easy."

But, "at some point, the doctor and patient need to think of a different strategy -- either stop the medication or switch medications," he added. "We should give the minimal amount for the patient to get well, and then stop."

More information

The U.S. National Library of Medicine has more information about heartburn.