What Was Known About Childhood Diabetes Mellitus Before the Discovery of Insulin?

It has been widely reported by historians that physicians were aware of two distinct types of diabetes mellitus by the 1880s, and that these were both similar to and the direct forerunners of type 1, juvenile-onset and type 2, adult-onset diabetes. The writings of prominent specialist physicians practicing just prior to the discovery of insulin in 1921–1922 were reviewed and there is little evidence that experts believed that adult and childhood diabetes were different. In fact, more than a decade passed after the discovery of insulin before diabetes in children and adults even began to be distinguished. Childhood diabetes was exceedingly rare in the early 20th century and diabetes was believed to be primarily a chronic disease of adults. It is interesting to speculate about what might have happened if the first pancreatic extract tests had been performed on adult-onset diabetics with insulin-resistant diabetes mellitus. Clearly, the results would have been disappointing and the discovery of insulin delayed. This essay explores how the test subject decision was made. It is fortuitous that a 14 year old boy with what was unequivocally type 1 diabetes was selected to be the first insulin recipient, and the rest is history.