Diabetes mellitus and bone disease in cystic fibrosis

Patients with cystic fibrosis are frequently affected with pancreatic insufficiency and are predisposed to the development of diabetes mellitus (DM) and bone demineralization. Cystic fibrosis-related diabetes mellitus is a clinical entity distinct from type 1 and type 2 diabetes, with important implications for the nutritional and pulmonary health of cystic fibrosis patients. This form of diabetes owes largely to insulin deficiency, but alterations in insulin sensitivity and hepatic glucose production have also been described. Therapy for cystic fibrosis-related diabetes differs substantially from type 2 DM, with careful attention to prandial glycemic excursions crucial to controlling its metabolic effects. Bone disease, including osteopenia and osteoporosis, also occurs with increased frequency in cystic fibrosis, owing to defects in intestinal absorption, chronic inflammation, lung disease, low body weight, and gonadal dysfunction. The pathogenesis, implications, diagnosis, and therapy of cystic fibrosis-related bone demineralization are discussed, with attention to recommended approaches to prevention of and treatment of established bone disease.