London, May 30 (IANS) Drugs used by millions of patients to treat indigestion and heartburn have been linked to an increased risk of the bone disease osteoporosis.

Research shows that long-term use of indigestion drugs, called proton pump inhibitors (PPIs), is linked with broken bones later in life, reports express.co.uk.

Osteoporosis affects an estimated three million people in Britain. One in three women and one in 12 men develop it at some point.

The National Institute for Health and Clinical Excellence recommends patients use PPI drugs for two to four weeks for indigestion. They work by blocking the action of cells called proton pumps, which produce stomach acid.

Although they are very effective, they should only be used for a short time to get the condition under control. But patients with chronic heartburn have to take them daily for up to two months.

The problem is many patients end up staying on the drugs permanently to keep symptoms at bay.

It is not clear how the drugs might damage bones. But one theory is that by blocking acid production they stop the body from absorbing calcium.

Two studies have raised fears over the drugs' effects.

In 2006, experts at the University of Pennsylvania found patients taking PPIs for more than a year were 44 percent more likely to suffer a hip fracture.

In 2008, a team at the University of Manitoba in Canada found a similar increase in risk among those taking the drugs regularly for five years.