Here's a look at diabetes, a disease that affects millions of people around the world. Diabetes is characterized by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. The disease can lead to serious complications such as blindness, kidney damage, cardiovascular disease, limb amputations and premature death. Facts Worldwide, the number of people living with the potentially fatal disease has quadrupled since 1980, to around 422 million, according to the World Health Organization (WHO). 34.2 million people in the United States have diabetes, about 10.5% of the population. Of this number, 7.3 million (21.4%) are undiagnosed. Diabetes is the seventh leading cause of death in the United States. There are several types of diabetes: Type 1, Type 2 and gestational diabetes. Prediabetes occurs when blood glucose levels are higher than normal but not yet high enough to be diagnosed as diabetes. Before developing Type 2 diabetes, people almost always have prediabetes. Research has shown that some long-term damage to the body may occur during prediabetes. Type 1 diabetes develops when the body's immune system destroys pancreatic beta cells, the only cells in the body that make insulin. This form of diabetes usually strikes children and young adults. Only 5-10% of people with diabetes have Type 1. Risk factors for Type 1 diabetes may be autoimmune, genetic or environmental. There is no known way to prevent Type 1 diabetes. Type 2 diabetes occurs when the body does not produce enough insulin or the cells do not use insulin properly. Type 2 diabetes is the most common form of diabetes and in adults, it accounts for about 90% to 95% of all diagnosed cases of diabetes. It is associated with older age, obesity, family history, physical inactivity and race/ethnicity. It is more common in African Americans, Latino Americans, American Indians, Asian Americans, Native Hawaiians and other Pacific Islanders. Type 2 diabetes in children and adolescents, although still rare, is being diagnosed more frequently. Gestational diabetes is a form of glucose intolerance diagnosed during pregnancy. It affects about 4% of all pregnant women. A diagnosis of gestational diabetes doesn't mean that a woman had diabetes before she conceived, or that she will have diabetes after giving birth. Other types of diabetes result from genetic conditions, surgery, medications, infections and other illnesses. Such types of diabetes account for 1% to 5% of all diagnosed cases. Possible Symptoms Frequent urination Excessive thirst Unexplained weight loss Extreme hunger Sudden changes in vision Numbness in hands or feet Tiredness Dry skin Slow healing wounds Frequent infections Complications Adults with diabetes have heart disease death rates about two to four times higher than adults without diabetes. The risk for stroke is two to four times higher among people with diabetes. People with diabetes are at high risk for high blood pressure Diabetes is the leading cause of new cases of blindness among adults aged 20-74 years. Diabetes is the leading cause of kidney failure. Between 60% and 70% of people with diabetes have mild to severe forms of nervous system damage or neuropathy. US Diabetes Statistics 1.5 million new cases are diagnosed every year in the United States. In 2015, about 88 million people 18 or older had pre-diabetes. About 210,000 people under 20 years old have type 1 or type 2 diabetes. $327 billion - Cost to treat diabetes in the US in 2017.