In type 1 diabetes, the body no longer makes insulin because the body's own immune system has attacked and destroyed the cells where insulin is made. The cause of this isn't entirely clear but it may include genetic risk factors and environmental factors. One theory is that type 1 diabetes may occur after having a specific virus.People with type 1 diabetes must take insulin every day to live. There is no known way to prevent or cure type 1 diabetes, but it can be controlled by keeping blood glucose (sugar) levels within a normal range.Causes of Type 2 DiabetesType 2 diabetes is the most common form of diabetes. In type 2 diabetes, the body either doesn't make enough insulin or can't use its own insulin as well as it should. The risk of having type 2 diabetes increases as a person gets older.The cause of type 2 diabetes is largely unknown, but genetics and lifestyle clearly play roles. Type 2 diabetes has been linked to obesity, genetic risk factors, and inactivity. Some racial and ethnic groups are at higher risk for type 2 diabetes. These include American Indians, African Americans, Hispanics/Latinos, Asian Americans and Pacific Islanders.There is no known way to cure type 2 diabetes, but it can be controlled by keeping the level of glucose (sugar) in the blood within a normal range.