Short answers, pulled from the story.
Diabetes mellitus is a group of common endocrine diseases characterized by sustained high blood sugar levels. It results either from reduced production of the hormone insulin by the pancreas or from the body's cells being unresponsive to insulin's effects.
Type 1 diabetes is an autoimmune condition in which a T cell-mediated attack destroys the insulin-producing beta cells of the pancreas, and it accounts for 5 to 10% of cases. Type 2 diabetes is marked by insulin resistance, accounts for more than 95% of cases, and stems primarily from lifestyle factors and genetics.
The classic symptoms of diabetes are the three Ps: polydipsia or excessive thirst, polyuria or excessive urination, and polyphagia or excessive hunger. These appear alongside weight loss and blurred vision, though about half of affected individuals may be asymptomatic.
The number of people diagnosed with diabetes worldwide rose from 200 million in 1990 to 828 million in 2024. It affects one in seven adults, and more than half of those affected are unaware of their condition.
Diabetes is diagnosed by a fasting plasma glucose level at or above 7.0 mmol/L, which is 126 mg/dL, or a plasma glucose at or above 11.1 mmol/L, which is 200 mg/dL, two hours after a 75 gram oral glucose load. A glycated hemoglobin, or HbA1C, at or above 48 mmol/mol, which is 6.5 percent, also confirms the diagnosis.
Type 1 diabetes requires insulin, ideally a basal bolus regimen of long-acting and short-acting insulin. Type 2 diabetes is generally first treated with metformin and lifestyle changes, with a treatment goal of keeping HbA1C below 7%.
The Canadians Frederick Banting and Charles Best isolated and purified insulin in 1921 and 1922, the first effective treatment for diabetes. The long-acting insulin NPH followed in the 1940s.