How does cystic fibrosis related diabetes occur?

• A. Autoimmune destruction of pancreatic beta cells
• B. Mucus obstruction of pancreatic beta cells, which prevents insulin secretion and may lead to beta cell destruction
• C. Insulin resistance due to obesity
• D. Exocrine pancreatic insufficiency causing low insulin production

Answer: (B)

Cystic fibrosis–related diabetes mainly arises from damage to the pancreatic beta cells caused by the CF disease process. Thick, sticky mucus blocks the pancreatic ducts, leading to chronic inflammation and fibrosis of the pancreas. This injures the islets and specifically reduces insulin production, so the body becomes insulin deficient.

This differs from autoimmune destruction seen in Type 1 diabetes, and from obesity-related insulin resistance typical of Type 2 diabetes, which CFRD does not primarily reflect. Exocrine pancreatic insufficiency is common in CF and signals pancreatic damage, but the diabetes comes from the impact on the endocrine pancreas and beta cells, not simply a lack of digestive enzymes.