Diabetes - Type 2 Diagnosis

  • Diagnosis

    Diabetes is a chronic disease in which the body makes little or no insulin, or is unable to use the insulin it makes. Insulin is a hormone produced by the pancreas that helps your body use the energy from sugar, starches, and other foods. When insulin is absent or ineffective, blood sugar (glucose) levels become higher than normal. Over time, high blood sugar levels can damage blood vessels and nerves, and lead to serious health problems such as blindness, kidney failure, heart attack, and stroke.

    Type 2 diabetes, previously called adult-onset diabetes or noninsulin-dependent diabetes mellitus (NIDDM), accounts for 90% of diabetes cases. While it tends to develop gradually after the age of 40, type 2 diabetes is now being diagnosed in many overweight children and young adults, and is beginning to reach epidemic proportions.

    Type 2 diabetes is associated with high levels of harmful blood fat (LDL cholesterol) and high blood pressure. The high blood glucose levels seen in type 2 diabetes cause high levels of a harmful blood fat (LDL cholesterol) and low levels of the good kind of blood fat (HDL cholesterol). This imbalance of cholesterol can lead to hardened arteries (atherosclerosis), which causes poor circulation and various other complications. Type 2 diabetes is also associated with high blood pressure.

    Type 2 diabetes occurs when your body responds inefficiently to the hormone insulin, which regulates blood sugar Figure 01. Insulin is secreted by the pancreas. Normally, when insulin interacts with cells, it starts a chain reaction that ends when simple sugar (glucose) from digested carbohydrates enters cells from the bloodstream and is turned into energy or fat.

    People with type 2 diabetes have cells that don't respond effectively to insulin. As a result of this inability to use insulin, glucose in the bloodstream goes unused, and can build to dangerous levels. This insulin resistance is pronounced in people with type 2 diabetes who are overweight or obese. Over time, type 2 diabetics may progress from having adequate or even greater than adequate amounts of insulin to insulin deficiency, as the insulin-producing cells in the pancreas “burn out.” This is why type 2 diabetics have blood sugar levels that become more difficult to control, and require increasing medication with time.

    Insulin resistance can be inherited, or can develop as a consequence of lifestyle. Twin studies show that diabetes is an inherited disorder; however, the genetic pattern of inheritance is not yet fully understood.

    Being overweight, having poor eating habits, and living a sedentary lifestyle also contribute to the risk of developing diabetes.

    Click to enlarge: Cellular mechanisms of diabetes (animation and audio)

    Figure 01. Cellular mechanisms of diabetes (animation and audio)

    You can have type 2 diabetes without having any symptoms. However, type 2 diabetes often causes frequent urination and thirst Table 01. Type 2 diabetes may come on so gradually that you don't even notice it. In these cases, the first symptoms you may experience will reflect nerve damage in your hands or feet because of impaired circulation. You may, however, feel the need to urinate frequently, or excrete a larger amount of urine than normal. These symptoms occur because your kidneys excrete extra water to dilute the sugar that has entered your urine. As your body excretes extra water, you will become dehydrated and thirsty.

    Later symptoms include weight loss despite increased hunger and food intake. This occurs because diabetics are unable to use their blood glucose for energy, so body fat is burned in an attempt to provide “fuel”. Other symptoms may include blurred vision, weakness and fatigue, recurring vaginal yeast infections, and skin infections.

    Table 1.  Common Symptoms of Type 2 Diabetes

    Increased thirst
    Frequent urination
    Weight loss
    Fatigue
    Numbness or tingling in the hands or feet
    Problems with sexual function
    Blurred vision
    Yeast infections, or other vaginal or urinary tract infections
    Skin infections or slow-healing cuts or sores

    Heredity and ethnicity can be risk factors for type 2 diabetes Table 02. Type 2 diabetes sometimes runs in families. Having a mother with the disease seems to be a particularly strong factor: research indicates that patients whose mothers have diabetes are twice as likely to get the disease as those whose father has it. Ethnic background influences risk as well. African Americans, Hispanics, and Native Americans account for a disproportionate number of type 2 diabetes cases. In fact, the Pima Indians of Arizona have the highest incidence in the world: 10 times that of the general U.S. population.

    Your risk for diabetes increases with age. The risk of developing type 2 diabetes increases after the age of 45, with significant increased risk in persons 65 years of age or older. However, as mentioned previously, type 2 diabetes is being diagnosed in more and more children and young adults who are obese and sedentary.

    Being overweight or obese increases your risk for type 2 diabetes. The vast majority of people with type 2 diabetes are obese.

    The combination of obesity, hypertension, and high cholesterol, known as the metabolic syndrome, is a risk factor for diabetes. This condition also puts people at risk for heart disease and strokes Hardening of the arteries (atherosclerosis), caused by accumulated cholesterol and other blood fats and cellular debris, is twice as common in people with diabetes. Therefore, diabetics have a higher risk for heart attacks and strokes than non-diabetics. This increase in cardiovascular risk in type 2 diabetics is associated with the combination of insulin resistance due to obesity, problems with lipid (fat) metabolism, and hypertension.

    Having diabetes during pregnancy, having delivered a large baby (more than 9 pounds), or having impaired glucose tolerance increases your chances of developing Type 2 diabetes.

    Table 2.  Risk Factors for Type 2 Diabetes

    Obesity (weighing 20% or more over desired body weight)
    Impaired glucose tolerance
    Having a parent or sibling with diabetes
    African-American, Hispanic, Asian-Americans/Pacific Islander, or Native-American ethnicity
    Age of 45 years or older
    Having delivered a baby weighing more than 9 pounds
    History of diabetes during pregnancy
    Blood pressure of 140/90 mmHg or higher
    HDL cholesterol of 35 mg/dL or lower and/or triglyceride level of 250 or higher

    To diagnose diabetes, your doctor will take your medical history and conduct a physical examination. Your doctor will check your height, weight, and blood pressure, and will look for evidence of nerve damage. Your doctor will also do an eye exam to look for a complication that results when blood vessels supplying the retina are damaged (retinopathy). The doctor will also examine your mouth, heart, skin, and feet (people with diabetes sometimes lose sensation in their feet, and may not notice sores that have been caused by trauma).

    Your doctor will run blood tests to confirm a diagnosis of diabetes. Your blood sugar level will help determine whether or not you have diabetes.Your doctor may do a random blood test, or may ask you to fast before coming to your appointment. A glucose concentration of 200 mg/dL or above with symptoms of diabetes on a random sample and one of 126 mg/dL or above on a fasting sample reveals diabetes. If your fasting level falls between 110 and 125 mg/dL, your doctor may wish to do another test (glucose tolerance test), which involves drinking a 75-g glucose solution and having your blood collected at one and two hours. At 2 hours, a glucose concentration of 200 mg/dL or higher is diagnostic of diabetes. If you have a fasting blood glucose between 110 and 125, you are considered to have impaired fasting glucose (IFG). If you have a two-hour value on a glucose tolerance test between 140 and 199 mg/dL, you are considered to have impaired glucose tolerance (IGT). Both IFG and IGT are risk factors for future diabetes and cardiovascular disease.

    Your doctor may also do a blood test called the hemoglobin A1C test (also referred to as glycohemoglobin or glycosylated hemoglobin test). This is a measure of blood sugar control over time (the preceding three months), and is the standard for predicting the risk of developing long-term complications. According to the American Diabetes Association, a hemoglobin A1C level of <7% in diabetics is the target value for blood sugar control.

    You should be screened for type 2 diabetes every three years starting at age 45. If you are younger than 45 but have risk factors for diabetes, you should be screened more frequently.

    Get regular exercise. Research is showing that exercise appears to lower your chance of getting diabetes. In one study, middle-aged men who did at least 40 minutes of brisk walking daily, slow swimming, bicycling, or other moderate-intensity physical activity had half the risk for developing Type 2 diabetes than did men who exercised less. If you have a family history of diabetes, the benefits of exercise for preventing diabetes are even greater. Regular exercise also helps to control weight and blood lipid (fat) levels.

    Pay close attention to your diet, and lose weight if you are overweight Figure 02. Leading a sedentary lifestyle and eating a nutrient-poor diet high in sugar, calories, and fat contributes to obesity, which is a major risk factor for diabetes. Getting exercise and eating a balanced diet can help you lose weight and prevent diabetes.

    Click to enlarge: Body mass index (BMI)

    Figure 02. Body mass index (BMI)

  • Prevention and Screening

    You should be screened for type 2 diabetes every three years starting at age 45. If you are younger than 45 but have risk factors for diabetes, you should be screened more frequently.

    Get regular exercise. Research is showing that exercise appears to lower your chance of getting diabetes. In one study, middle-aged men who did at least 40 minutes of brisk walking daily, slow swimming, bicycling, or other moderate-intensity physical activity had half the risk for developing Type 2 diabetes than did men who exercised less. If you have a family history of diabetes, the benefits of exercise for preventing diabetes are even greater. Regular exercise also helps to control weight and blood lipid (fat) levels.

    Pay close attention to your diet, and lose weight if you are overweight Figure 02. Leading a sedentary lifestyle and eating a nutrient-poor diet high in sugar, calories, and fat contributes to obesity, which is a major risk factor for diabetes. Getting exercise and eating a balanced diet can help you lose weight and prevent diabetes.

    Click to enlarge: Body mass index (BMI)

    Figure 02. Body mass index (BMI)

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