Type 2 diabetes is closely linked to being overweight, inactive, and having a family history of diabetes. Nearly two-thirds of U.S. adults are overweight or obese, with a body mass index (BMI) of 25 or more. Among youth 2 to 19 years old, 17 percent are overweight (i.e., have a BMI at the 95th percentile or more for their age and sex) — triple the rate in 1980. About the same percentage of youth have a BMI between the 85th and 95th percentile for their age and sex, putting them at risk for becoming overweight.

Type 1 diabetes, which affects up to 1 million people in the United States, develops when the body's immune system destroys the insulin-producing beta cells of the pancreas. This form of diabetes usually strikes children and young adults, who need several insulin injections a day or an insulin pump to survive. The HEALTHY study is aimed at preventing type 2 diabetes. Other NIH-funded studies are trying to prevent type 1 diabetes in centers nationwide: http://www.nih.gov/news/pr/jun2006/niddk-09.htm.

The longer a person has diabetes, the greater the chances of developing serious damage to the eyes, nerves, heart, kidneys, and blood vessels. ?We're already seeing kids in their late teens with early complications from type 2 diabetes,? said Francine Kaufman, M.D., director of the Comprehensive Childhood Diabetes Center at the Childrens Hospital Los Angeles, where type 2 diabetes accounts for more than 20 percent of new childhood diabetes cases. ?As a society, we need to address the obesity epidemic if we?re going to have any success containing the rising rate of type 2 diabetes in kids. A logical place to start is in our schools.?

Once seen only in adults, type 2 diabetes has been rising steadily in youth. While there are no national data on the prevalence of type 2 diabetes in youth, clinics around the country are reporting that more young people, especially from minority groups, are developing the disease. Studies in Cincinnati, Los Angeles, San Antonio, and other cities conclude that cases of type 2 diabetes in youth have risen dramatically since 1994, when less than 5 percent of new childhood diabetes cases were type 2. By 1999, type 2 diabetes accounted for 8 to 45 percent of new childhood diabetes cases, varying by geographic location. Some diabetes centers are now seeing more new cases of type 2 diabetes than type 1.

Nearly 21 million people in the United States ? 7 percent of the population ? have diabetes, the most common cause of blindness, kidney failure, and amputations in adults and a major cause of heart disease and stroke. Type 2 diabetes accounts for up to 95 percent of all diabetes cases in adults, and about one-third of those affected don?t know they have it. The prevalence of type 2 diabetes has risen dramatically in the last 30 years, due mostly to the upsurge in obesity. In addition, at least 54 million U.S. adults age 20 and older have pre-diabetes, which independently raises the risk of developing type 2 diabetes and cardiovascular disease.