Diabetes mellitus (DM) is a disease in which altered carbohydrate metabolism leads to high blood glucose levels (Huether & Tomky, 1998). DM has several causes and can be categorized into several types (Table 10-1). DM also frequently occurs with other diseases and conditions, such as hypertension, metabolic syndrome, cardiac disease (Nathan et al., 2005) and vascular disease (Ganne et al., 2007).

Each year since 1997, the number of new diabetic cases has increased nationwide (CDC, 2007a). In 2004 alone, approximately 1.4 million adults were newly diagnosed with the disease (CDC-e, 2007a). The Centers for Disease Control and Prevention (CDC, 2005) estimate that 21 million Americans have diabetes, and an additional 41 million are prediabetic (CDC, 2005b). Prediabetes manifests as impaired glucose tolerance or impaired fasting glucose. The incidence of diabetes increases with advancing age, with most cases attributable to type 2 diabetes. However, although the incidence of diabetes increased for all age groups from 1997 to 2004 (CDC-c), the largest increase occurred among individuals age 18 to 44 (45%).

Type 2 diabetes occurs almost twice as often in African Americans and one and a half times as often in Hispanics as in Caucasians (CDC, 2007b). Native Americans by far are the ethnic group most highly at risk. More than one fourth of Native American adults living in the southeastern United States (27.8%) have diabetes (CDC, 2005a). Family history, advancing age (over 40), and gestational diabetes are uncontrollable risk factors for type 2 diabetes. However, hypertension, obesity, and lack of exercise are modifiable risk factors. Recent research has found genetic risk factors for diabetes: for type 2, these are human INS (insulin) gene promoter (Karaca et al., 2007), genes TCF7L2 (Owen & McCarthy, 2007) and CDKAL1 (Steinthorsdottir et al., 2007), and a mutant 128R allele of the E-selectin gene (Abu-Amero et al., 2007); for gestational diabetes, the genetic risk factor is a INS-VNTR class III gene (Litou et al., 2007).

Even though it is underreported, diabetes is the sixth leading cause of death in the United States. People with diabetes are twice as likely to die of heart disease and stroke and one and one half times more likely to have hypertension (CDC, 2005a). The incidence of retinopathy, nephropathy, and neuropathies is significantly higher in the diabetic population (CDC, 2005a), and these conditions are worsened by periods of poorly controlled serum glucose levels (–Diabetic control study, Genuth, 2006). Diabetes is the major contributing factor in new cases of blindness, end-stage renal disease, and nontraumatic lower limb amputations. The CDC’s National Center for Chronic Disease Prevention and Health Promotion estimates the death risk for individuals with diabetes to be twice that of the nondiabetic population (CDC, 2005c). Recent research has revealed racial and gender disparities among Medicare patients treated for diabetes mellitus; Caucasians appear to receive better treatment than African Americans, and women receive less intensive cholesterol treatment than men (Chou et al., 2007).