Diabetes Mellitus Type II

Risk: Gender, age, family history of diabetes, and ethnic background are important risk factors for developing type 2 diabetes. Risk is greater among women than men and greater among inactive rather than active individuals of either sex. Individuals with a family history of type 2 diabetes in a parent or sibling, who are over the age of 45, or who are obese (body mass index [BMI] greater than 30) have a greater likelihood of developing the disease. Ninety percent of individuals with type 2 diabetes are obese (Votey). A previously identified abnormal fasting plasma glucose, high blood pressure, and high cholesterol (generally total cholesterol >200mg/dL) are considered to be major risk factors for type 2 diabetes. This disorder is more common among Hispanics, Native Americans, blacks, Asians and Pacific Islanders than non-Hispanic whites (Votey).

Incidence and Prevalence: An estimated 8% of the population of the US or 23.6 million people diabetes and another 54 million have pre-diabetes ("National Diabetes Fact Sheet"). Pre-diabetes is a condition in which blood glucose levels are higher than normal but not high enough to diagnose diabetes. Each year, about 1.6 million people aged 20 years or older are newly diagnosed with diabetes ("National Diabetes Fact Sheet"). Approximately 90% of these individuals have type 2 diabetes (Lithgary).

Incidence of type 2 diabetes mellitus is rising and is expected to increase worldwide in the coming decade. Incidence is also rapidly increasing in US children and adolescents due to the rise of childhood obesity; 2 million American adolescents have pre-diabetes ("National Diabetes Fact Sheet"). The incidence of type 2 diabetes now exceeds type 1 diabetes in the pediatric population. Increases among Hispanic and African-American children are greater than among other ethnic populations.

History: Individuals often are asymptomatic and only occasionally report the classic symptoms of diabetes mellitus, including increased urination (polyuria), excessive thirst (polydipsia), and excessive hunger (polyphagia). The individual may complain of frequent skin infections that are slow to heal, itching, blurred vision, tingling, numbness, and pain in the arms and legs. There may be a feeling of general fatigue and drowsiness. Women may experience chronic vaginal infections (vaginitis).

Physical exam: High blood pressure is present in at least half the individuals with type 2 diabetes, and obesity is a very common finding. The feet and lower legs are examined carefully for signs of ulceration, persistent infection, or gout. Blood pressure in the leg may be lower than in the arm (ankle-brachial index) indicating poor circulation to the extremities. A decreased sensation of pain may be detected in the legs and feet consistent with peripheral nerve dysfunction (diabetic neuropathy). An eye exam may reveal changes in the blood vessels, bleeding, and yellow or white patches in the retina (diabetic retinopathy).

Tests: Diagnosis depends primarily on plasma glucose levels, especially an elevated level of fasting plasma glucose (FPG) and the presence of impaired glucose tolerance (IGT). Glucose tolerance testing measures and compares fasting and non-fasting blood glucose levels to evaluate glucose metabolism. The oral glucose tolerance test measures blood glucose at half-hour intervals within 2 hours after drinking a set amount of a glucose solution. Individuals with diabetes show abnormal rises in blood glucose (hyperglycemia) within the 2-hour period.

Urinalysis is performed to measure the amount of glucose excreted in the urine; elevated urine glucose (glycosuria) is a typical abnormal finding in diabetes. The absence of ketosis (abnormally elevated concentration of ketones in the blood) is a primary feature that distinguishes type 2 from type 1 diabetes. A blood chemistry profile is performed to evaluate lipid levels, fluid and electrolyte balance, and to measure serum creatinine, an indicator of kidney function. Periodic testing of the amount of glucose bound to a protein (hemoglobin) in red blood cells (glycosylated hemoglobin or HbA1c) may be used to estimate plasma glucose levels over the preceding 1 to 3 months, and may help the physician recommend changes in diet, exercise, and insulin therapy. However, lack of standardization of assays for HbA1c has discouraged physicians from using it for diagnosis even though it may be used to monitor effectiveness of treatment (Kronenberg).