Diabetes is a chronic, metabolic disease characterized by elevated levels of blood glucose (or blood sugar), which leads over time to serious damage to the heart, blood vessels, eyes, kidneys and nerves, affecting all age groups. It is one of the leading causes of mortality and morbidity worldwide. n diabetes type 1, the pancreas does not make insulin, because the body's immune system attacks the islet cells in the pancreas that make insulin. In diabetes type 2, the pancreas makes less insulin than used to, and your body becomes resistant to insulin