Long-term use of proton pump inhibitors may reduce bone strength.
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Acid reflux disease is the most common upper gastrointestinal disease in the Western world. Proton pump inhibitors -- medications many people reach for when dealing with persistent heartburn -- are among the most widely used medications in the U.S. Proton pump inhibitors, including omeprazole (Prilosec), lansoprazole (Prevacid), esomeprazole (Nexium) and others, effectively suppress stomach acid and alleviate acid reflux symptoms. These medications may increase your risk for hip, wrist or spine fractures.
Proton pumps are specialized proteins embedded within the membranes of cells throughout your body. By moving hydrogen ions from one side of a membrane to the other, proton pumps create electrical and chemical "gradients" that can be used to generate energy or acidify a cell's environment. The proton pumps are responsible for producing stomach acid. Similar pumps in specialized cells, called osteoclasts, within your bones allow them to remodel your bones. Proton pump inhibitors interfere with all proton pumps in your body.
Calcium is 1 of the principal minerals in bone, and an adequate supply of calcium is essential for bone health. Stomach acid helps your body absorb calcium from food. Researchers theorize that reduced calcium absorption could partially account for the increased incidence of hip fractures seen in people who regularly use proton pump inhibitors. A December 2010 review in "Current Gastroenterology Reports" established that this question is far from being answered, as it is not even clear if proton pump inhibitors interfere with calcium absorption.
Increased Bone Breakdown
Your body is adept at compensating for mechanisms that are disrupted by medications. When the acid levels in your stomach decline as the result of proton pump inhibitor therapy, cells in your stomach lining release gastrin. This hormone stimulates neighboring acid-producing cells to work harder. The elevated gastrin level is usually not sufficient to overcome the effects of proton pump inhibitors on stomach acid secretion, but it may have other effects.
In addition to stimulating acid-producing cells within your stomach, gastrin stimulates your parathyroid gland, which releases another hormone that accelerates the removal of calcium from your bones. It is not yet clear if parathyroid stimulation contributes to the fractures associated with proton pump inhibitor therapy.
Altered Bone Remodeling
Bone is a living, dynamic tissue that is constantly being remodeled. Bone remodeling is dependent on 2 cell types -- osteoclasts and osteoblasts -- that reabsorb and rebuild bone in a balanced fashion. This allows for bone repair and growth without sacrificing strength. The proton pumps in osteoclasts allow them to acidify and break down bone tissue that needs repair and replacement. By interfering with the proton pumps within osteoclasts, proton pump inhibitors may alter the density of your bones. This is only 1 of several mechanisms that could play a role in heightened fracture risk among proton pump inhibitor users.
Putting It in Perspective
Proton pump inhibitors are generally well tolerated, and their use has revolutionized the treatment of acid reflux, ulcers and other conditions associated with excess acid. Most studies show the risk for fractures in people who use proton pump inhibitors is quite low -- about 1.5 times the risk of non-users. This elevated risk is confined to people who take high doses, use the medications for 2 years or more and have at least 1 other risk factor for fractures, such as alcohol abuse, diabetes, long-term use of medicinal steroids or kidney disease. So, as with all medications, the risks and benefits of treatment must be weighed on a personal basis. Your doctor can help you decide if Prilosec or any other proton pump inhibitor is appropriate for you.