For centuries, diabetes meant an early death sentence. After the discovery of insulin, researchers then came to believe that all people with type 1 diabetes would inevitably experience complications. But in 2007, researchers at the Joslin Diabetes Center in Boston conducted a study that proved people with type 1 diabetes can live long, complication-free lives. The 50-Year Medalist Study, published in Diabetes Care, analyzed survey data on 326 patients who had type 1 diabetes for 50 years or longer. To the researchers' surprise, nearly half of the patients showed no sign of complications like kidney disease, retinopathy, or nerve damage.

In a follow-up, yet-to-be-published study, researchers led by George King, MD, director of research and head of vascular cell biology and complications at the Joslin Diabetes Center and professor of medicine at Harvard Medical School, examined eye, heart, nerve, and beta cell functions of 400 medalists. King and his colleagues confirmed the earlier research: Approximately 30 percent of the patients didn't have significant eye or kidney disease. And even more surprising: The researchers found no connection between a person's A1C level and incidence of complications.

"Most of these people developed diabetes in the '40s, '50s, and tight glucose control was not possible. They must have some factor in them that's protective against complications," says King, who plans to study biomarkers, cell markers, and genetic markers that may protect against the complications.

In the same study, King and colleagues made a landmark discovery that suggests a segment of the medalist group still has the ability to produce insulin. The findings, presented this year at the American Diabetes Association's 68th Scientific Sessions, showed that about 17 percent of participants continued to make a significant amount of c peptide in their blood even after living with diabetes for an average of 58 years. (C peptide levels indicate how much insulin is being produced by the beta cells.)

While researchers aren't sure what causes these patients to retain the capacity to produce insulin, King says he and his colleagues plan to study the presence of beta cells in an additional 300 medalists. "If we can find that these medalists with over 50 or 70 years of diabetes [have beta cells], once we have some sort of treatment potentially we have some way to treat those who have had the disease for 10, 15 years," he says, noting that any would-be treatment is still far off. But despite ongoing research, this much is true as of now: Living a healthy, long life with type 1 diabetes is by no means impossible.