Now doctors are studying ways to cure the disease before it happens and even get rid of the disease in people who already have it.
It can be a pain, but it's a necessity for millions. Checking your insulin level every day is something Kerby Bennet is trying to avoid. A few years ago her twin sister Taylor was diagnosed with type-one diabetes.
"It was a shock to us, especially because she was 17 when she was diagnosed," Kerby said.
Because her identical twin has it, Kerby has a 65 percent chance of developing the disease too
"It's nerve wracking," Kerby said.
Now, she's the first person to enroll in a clinical trial at Vanderbilt University testing the drug Teplizumab.
"It's been well studied in individuals who have been newly diagnosed with diabetes," Dr. William Russell, director of pediatric endocrinology and diabetes at Vanderbilt University said. "What if we take someone who is at high risk to develop diabetes, can we actually prevent it?"
The drug battles an immune system protein called CD3. The goal is to find out if it can also stop the destruction of the insulin-producing cells in the pancreas before diabetes occurs. Meanwhile researchers at the University of Colorado are curing it in animals. By isolating the specific t-cells that attack the pancreas, they developed a drug that can stop diabetes from developing and even reverse it in mice that already have it.
Kerby hopes the drugs will help prevent her from developing diabetes and someday cure her twin sister.
"I think research like this makes it possible," Kerby said.
Researchers will follow Kerby for up to four years. Doctors say their ultimate goal for the trial is to enroll 150 people in the U.S. and at a few foreign sites. For more information on how to enroll go to www.diabetestrialnet.org