Editor’s note: This is the second in a two-part series commemorating the 100-year anniversary of the first use of insulin in humans. Part 1 of this series examined the rivalry behind the discovery and use of insulin.
One hundred years ago, teenager Leonard Thompson was the first patient with type 1 diabetes to be successfully treated with insulin, granting him a reprieve from what was a certain death sentence at the time.
Since then, research has gathered pace. In the century since insulin’s discovery and first use, recombinant DNA technology has allowed for the engineering of the insulin molecule, providing numerous short- and long-acting analog versions. At the same time, technological leaps in automated insulin delivery and monitoring of blood glucose ensure more time with glucose in range and fewer life-threatening complications for those with type 1 diabetes fortunate enough to have access to the technology.
In spite of these advancements, there is still scope for further evolution of disease management, with the holy grail being the transplant of stem cell–derived islet cells capable of making insulin, ideally encased in some kind of protective device so that immunosuppression is not required.
Indeed, it is not unreasonable to “hope that type 1 diabetes will be a curable disease in the next 100 years,” said Elizabeth Stephens, MD, an endocrinologist who has type 1 diabetes and practices in Portland, Ore.
Type 1 diabetes: The past 100 years
The epidemiology of type 1 diabetes has shifted considerably since 1922. A century ago, given that average life expectancy in the United States was around 54 years, it was pretty much the only type of diabetes that doctors encountered. “There was some type 2 diabetes about in heavier people, but the focus was on type 1 diabetes,” noted Dr. Stephens.
Originally called juvenile diabetes because it was thought to only occur in children, “now 50% of people are diagnosed with type 1 diabetes ... over [the age of] 20,” explained Dr. Stephens.
In the United States, around 1.4 million adults 20 years and older, and 187,000 children younger than 20, have the disease, according to data from the National Diabetes Statistics Report 2020 by the Centers for Disease Control and Prevention. This total represents an increase of nearly 30% from 2017.
Over the years, theories as to the cause, or trigger, for type 1 diabetes “have included cow’s milk and [viral] infections,” said Dr. Stephens. “Most likely, there’s a genetic predisposition and some type of exposure, which creates the perfect storm to trigger disease.”
There are hints that COVID-19 might be precipitating type 1 diabetes in some people. Recently, the CDC found SARS-CoV-2 infection was associated with an increased risk for diabetes (all types) among youth, but not other acute respiratory infections. And two further studies from different parts of the world have recently identified an increase in the incidence of type 1 diabetes in children since the COVID-19 pandemic began, but the reasons remain unclear.
The global CoviDiab registry has also been established to collect data on patients with COVID-19–related diabetes.
The million-dollar question: Is COVID-19 itself is propagating type 1 diabetes or unmasking a predisposition to the disease sooner? The latter might be associated with a lower type 1 diabetes rate in the future, said Partha Kar, MBBS, OBE, national specialty advisor, diabetes, for National Health Service England.
“Right now, we don’t know the answer. Whichever way you look at it, it is likely there will be a rise in cases, and in countries where insulin is not freely available, healthcare systems need to have supply ready because insulin is lifesaving in type 1 diabetes,” Dr. Kar emphasized.