What is the underlying mechanism of type 1 diabetes?

• A. Autoimmune destruction of insulin-producing beta cells
• B. Obesity-induced insulin resistance
• C. Pancreatic exocrine deficiency
• D. Excess glucagon production

Answer: (A)

Autoimmune destruction of insulin-producing beta cells in the pancreatic islets leads to absolute insulin deficiency. In type 1 diabetes, the immune system—often involving autoreactive T cells and autoantibodies against beta-cell antigens—gradually eliminates these cells. As insulin production drops, glucose cannot be effectively taken up by tissues, causing hyperglycemia and the need for insulin therapy. This autoimmune beta-cell loss distinguishes it from type 2 diabetes, where insulin resistance (often linked to obesity) is the primary issue. Pancreatic exocrine deficiency would affect digestive enzymes, not insulin production, and while excessive glucagon can worsen glucose levels, it is not the root mechanism of type 1 diabetes.