Diabetes is a serious, life-long disease. It can lead to problems such as heart disease, stroke, vision loss, kidney disease, and nerve damage. More than 8 million people in the United States have type 2 diabetes and dont know it. Many people dont find out they have diabetes until they are faced with problems such as blurry vision or heart trouble. Certain factors can increase your risk for diabetes, and its important to know what they are. Type 1 Diabetes Type 1 diabetes is an autoimmune disease. In an autoimmune reaction, antibodies, or immune cells, attach to the bodys own healthy tissues by mistake, signaling the body to attack them. At present, scientists do not know exactly what causes the body's immune system to attack the cells, but many believe that both genetic factors and environmental factors, such as viruses, are involved. Studies are now underway to identify these factors and prevent type 1 diabetes in people at risk.  Learn more about the causes of type 1 diabetes.  Type 2 Diabetes Type 2 diabetes -- the most common form -- is linked closely to overweight and obesity, high blood pressure, and abnormal cholesterol levels. Many people with type 2 diabetes are overweight. Being overweight can keep your body from using insulin properly. Genes also play an important role in a person's risk for type 2 diabetes. Having certain genes or combinations of genes may increase or decrease a persons risk for developing the disease.  Here are the risk factors for type 2 diabetes. -  being over 45 years of age  -  being overweight or obese  - having a first-degree relative -- a parent, brother, or sister -- with diabetes  - being African American, American Indian or Alaska Native, Asian American or Pacific Islander, or Hispanic American/Latino. (Watch the video to learn more about native Americans and diabetes risk. To enlarge the video, click the brackets in the lower right-hand corner. To reduce the video, press the Escape (Esc) button on your keyboard.) being over 45 years of age being overweight or obese having a first-degree relative -- a parent, brother, or sister -- with diabetes being African American, American Indian or Alaska Native, Asian American or Pacific Islander, or Hispanic American/Latino. (Watch the video to learn more about native Americans and diabetes risk. To enlarge the video, click the brackets in the lower right-hand corner. To reduce the video, press the Escape (Esc) button on your keyboard.) - having gestational diabetes, or giving birth to at least one baby weighing more than 9 pounds  - having blood pressure of 140/90 or higher, or having been told that you have high blood pressure.  - having abnormal cholesterol levels -- an HDL cholesterol level of 35 or lower, or a triglyceride level of 250 or higher  - being inactive or exercising fewer than three times a week.  - having polycystic ovary syndrome, also called PCOS (women only)  - on previous testing, having prediabetes (an A1C level of 5.7 to 6.4 percent), impaired glucose tolerance (IGT) or impaired fasting glucose (IFG)  - history of cardiovascular disease (disease affecting the heart and blood vessels). having gestational diabetes, or giving birth to at least one baby weighing more than 9 pounds having blood pressure of 140/90 or higher, or having been told that you have high blood pressure. having abnormal cholesterol levels -- an HDL cholesterol level of 35 or lower, or a triglyceride level of 250 or higher being inactive or exercising fewer than three times a week. having polycystic ovary syndrome, also called PCOS (women only) on previous testing, having prediabetes (an A1C level of 5.7 to 6.4 percent), impaired glucose tolerance (IGT) or impaired fasting glucose (IFG) history of cardiovascular disease (disease affecting the heart and blood vessels).  Learn more about the causes of type 2 diabetes.  Prediabetes and Type 2 Diabetes Before people develop type 2 diabetes, they usually have prediabetes -- a condition in which blood glucose levels are higher than normal, but not high enough for a diagnosis of diabetes. People with prediabetes are more likely to develop diabetes within 10 years and also are more likely to have a heart attack or stroke. Prediabetes is increasingly common in the U.S. adult population. In 2012, about 86 million people in the U.S. had pre-diabetes, and 51% of those 65 or older had prediabetes. Learn more about prediabetes.  Gestational Diabetes Some women develop diabetes during the late stages of pregnancy. This is called gestational diabetes. Although this form of diabetes usually goes away after the baby is born, a woman who has had it has a lifelong risk for developing diabetes, mostly type 2.