The number of Americans with diabetes have increased to nearly 26 million as more people are developing the disease and many who have it are living longer, says the Centers for Disease Control and Prevention (CDC).

An estimated 79 million adults in the United States have prediabetes, a condition in which blood sugar levels are higher than normal, but not high enough to be diagnosed as diabetes. Prediabetes raises a person's risk of type 2 diabetes, heart disease and stroke.

In a study published last year, CDC projected that as many as 1 in 3 U.S. adults could have diabetes by 2050 if current trends continue.

In 2008, about 23.6 million people in the United States had diabetes and 57 million adults were classified as prediabetes, according to a study by the Centers for Disease Control.

Diabetes affects 8.3 percent of Americans of all ages, and 11.3 percent of adults aged 20 and older, according to the National Diabetes Fact Sheet for 2011. About 27 percent of those with diabetes - 7 million Americans - do not know they have the disease. Prediabetes affects 35 percent of adults aged 20 and older.

Diabetes, which is the seventh leading cause of death in the United States, is a disease in which blood glucose levels are above normal. It is marked by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. Diabetes can cause serious health complications such as heart attacks, strokes, high blood pressure, kidney failure, blindness and amputations of feet and legs. Diabetes costs $174 billion annually, including $116 billion in direct medical expenses.

These distressing numbers show how important it is to prevent type 2 diabetes and to help those who have diabetes manage the disease to prevent serious complications such as kidney failure and blindness, said Ann Albright, director of CDC's Division of Diabetes Translation. We know that a structured lifestyle program that includes losing weight and increasing physical activity can prevent or delay type 2 diabetes.