Nearly 21 million people in the United States are living with diabetes. New research has found a major cause of type 2 diabetes and an old drug that could treat it.

Treating type 2 diabetes has been a tough challenge for doctors.

"None of the currently available medications are perfect, and one of the biggest problems we have with the current medications is they don't really treat the basic problem," said Dr. Steve Shoelson.

But Dr. Shoelson says the drug Salsalate could change that. It's an anti-inflammatory drug for arthritis that's been around since the 1800s.

"It's strange that we are using a drug that has been around for a long time to treat a disease that has been around for a long time," said Dr. Shoelson.

New research shows a protein that triggers inflammation is turned on in overweight people. The inflammation leads to insulin resistance and type 2 diabetes. Salsalate shuts off that protein.

"We think getting at the cause may have beneficial effects that we have not even anticipated," said Dr. Shoelson.

An early study shows the drug significantly improves blood sugar levels.

"The people who got no drug at all had absolutely no change in their blood sugars," said Dr. Shoelson.

Jerry Silva was in that early study and saw his blood sugars drop.

"I tend to be the kind of person who does not like to take medications if I don't have to," said Silva.

Since the study ended, he's lost 20 pounds. Instead of drugs, he now controls his diabetes with diet and exercise.

A large study is now underway to find out how much impact this drug will have.

The drug also lowers triglyceride levels, and it may reduce the risk of heart disease as well.

Researchers are currently recruiting patients for the larger trial on diabetes at 16 sites across the country.