Diabetes is a disease in which the level of glucose in the blood is too high. Glucose—a sugar needed by all cells of the body for energy—is normally transported to the cells with the help of the hormone insulin, which is produced by the pancreas. In type 1 diabetes, which is partly genetically inherited, the pancreas cannot make enough insulin because its insulin-producing cells have been destroyed by the body's own immune system. Thus, glucose accumulates in the blood. In contrast, people with type 2 diabetes can produce insulin, but their bodies are unable to utilize it effectively. Type 2 diabetes may be caused by lifestyle factors, such as high consumption of sugar, in addition to genetics. Type 1 diabetes has a lower prevalence than type 2, accounting for just five to ten percent of diabetes cases. The two conditions also differ by age of onset. Type 1 diabetes typically develops during childhood, while type 2 most commonly occurs in mid- to late adulthood. What is the main idea of the passage?