According to National Diabetes Education Program, "diabetes is a group of diseases marked by high levels of blood glucose resulting from defects in insulin production, insulin action, or both." Diabetes can have a harmful effect on most organ systems in the human body; it is a frequent cause of renal disease and lower-extremity amputation, and a leading cause of blindness among working age adults. Persons with diabetes are also at increased risk for ischemic heart disease, neuropathy, and stroke. The prevalence of diagnosed type 2 diabetes increased sixfold in the latter half of the last century according to the Centers for Disease Control and Prevention (CDC). Diabetes risk factors such as obesity and physical inactivity have played a major role in this dramatic increase. Age, race, and ethnicity are also important risk factors. The CDC estimates the direct economic cost of diabetes in the United States to be about $100 billion per year. This figure does not take into account the indirect economic costs attributable to potential work time lost to diabetes- related illness or premature death.