A new study conducted in mice revealed that over the long term, Avandia (rosiglitazone) used by millions of diabetes patients, may lead to bone loss.

According to researchers that tried the drug on lab mice, the mice administered the drug had increased production of osteoclasts, cells whose main function is to degrade bone.

Bones in the body are healthy when it is maintained a balance between osteoclasts and osteoblasts, the cells that build bone up. If any of these two cells suffers changes in number, bones become thinner, more fragile and easy to fracture.

The finding reported in this week’s online issue of Nature Medicine explained why people suffering from diabetes could have an increased risk of fractures.

"Our study suggests that long-term rosiglitazone usage in the treatment of type II diabetes may cause osteoporosis due to both increased bone resorption and decreased bone formation. Because Avandia is effective in controlling glucose and restoring the body's sensitivity to insulin, we do not recommend that people stop their treatment. You must balance the benefits against the complications," said study senior author Ron Evans, a professor at the Salk Institute for Biological Studies in La Jolla, Calif.

The drug, manufactured by GlaxoSmithKline, together with four other diabetes drugs from the same class, has already been found to raise a patient risk to develop heart disease and heart attacks. The U.S. Food and Drug Administration gave them “black box” warning, which is the agency’s strongest label.

Millions of people worldwide are living with diabetes most of them being administered Avandia to help control their blood sugar.

The finding contributes to a better understanding of the drug’ s side effect and provides a basis for developing a new drug, which can eliminate it.

The researchers advised patients who are on Avandia treatment to consider other alternatives to treat their disease.

"Anyone who is already at risk for osteoporotic fractures should consider an alternative anti-diabetic drug. There are many alternatives," said Paul Brandt, an associate professor of neuroscience and experimental therapeutics at Texas A&M Health Science Center College of Medicine, in College Station.

The Howard Hughes Medical Institute and the National Institutes of Health funded the research.

More information on diabetes drugs is found on the U.S. Food and Drug Administration.