Type 1 diabetes occurs when the body doesn't produce insulin at all, and type 2 diabetes happens when the body can't make enough insulin, or properly use it. Insulin is a hormone that allows glucose (blood sugar) to enter the body's cells and provide fuel for everyday activities. Type 2 diabetes is the most common type of diabetes, accounting for 90 to 95% of diabetes cases. The exact cause of the disease is unknown. However, it sometimes runs in families. Although a person can inherit a tendency to develop type 2 diabetes, it usually takes another factor, such as obesity, to bring on the disease. It is a chronic disease with no known cure. Risk factors for type 2 diabetes include a family history of diabetes; being overweight; not exercising regularly; being a member of certain racial and ethnic groups, such as African-Americans, Hispanic Americans, and Native Americans; a low level HDL (high density lipoprotein, the "good" cholesterol); or a high triglyceride level. Some people who have type 2 diabetes don't exhibit symptoms, and one-third of all people with diabetes don't know they have the disease. In order to screen for type 2 diabetes, people age 45 and older should have their blood sugar tested every three years. After an overnight fast, normal blood sugar levels should be 99 mg/dL or lower. The goal of type 2 diabetes treatment is to keep blood sugar levels as close to normal as possible. The key to accomplishing this is to monitor blood sugar levels regularly. Physical activity and meal planning are also important because they can help control blood sugar. However, sometimes, these are not enough and either oral medications and/or insulin must be used. Type 2 diabetes treatment and daily management are vital because the disease can cause serious complications. People with diabetes can develop heart disease or have strokes at an earlier age than people without it. In addition, uncontrolled diabetes can contribute to eye disorders and blindness, kidney failure, and nerve damage. Type 1 diabetes accounts for 5 to 10 percent of all diagnosed cases of diabetes in the United States. Type 1 diabetes usually develops in children or young adults, but it can start at any age. The disease often appears suddenly. In children, symptoms may be similar to those of the flu. The cause of type 1 diabetes is unknown, but it is believed that genetic and environmental factors (possibly viruses) may be involved. What is known is that the body's immune system attacks and destroys the insulin-producing cells in the pancreas. When glucose cannot enter the cells, it builds up in the blood, depriving the cells of nutrition. Complications that may result from type 1 diabetes include heart disease, kidney disease, eye problems, neuropathy (nerve problems), and foot problems. People with type 1 diabetes must have daily injections of insulin to keep their blood sugar level within normal ranges. Other parts of treatment may include adapting a more healthy diet (to better manage blood sugar levels), exercising (to achieve a healthy weight and help the body better use blood sugar), daily monitoring of blood sugar levels, careful self-monitoring of ketone levels in the urine several times a day, and checking hemoglobin A1c levels regularly.