70 years ago this year, a researcher at University College of the West Indies in Jamaica published a paper in The Lancet describing a case series of patients with diabetes who did not have the typical hallmarks of type 1 or type 2 disease. They were young, underweight, resistant to insulin, and did not tend to have ketoacidosis. The condition was coined J-type diabetes, after Jamaica, and it was briefly recognised by WHO as malnutrition-related diabetes. However, WHO removed it from its...