Definition

Type 2 diabetes is a disorder in which the body is resistant to high levels of insulin. Insulin is a hormone produced by the pancreas that helps the body convert food into energy. Without insulin, glucose (sugar) from the food you eat cannot enter cells. This causes glucose to build up in the blood. Meanwhile, your body tissues are starved for energy. However, in type 2 diabetes, there is plenty of insulin but the cells are resistant to its action.

Long-term, high blood sugar levels can damage the kidneys, eyes, nerves, and other tissues.

The Pancreas

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Causes

Two conditions contribute to type 2 diabetes:

  • Insulin resistance related to excess body fat (In this case, the body is unable to effectively use the insulin it produces.)
  • Failure of the body to make an adequate amount of insulin

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

  • Age: 40 or older
  • Sex: more common in older women than men
  • Obesity or being overweight (especially excess weight in the upper body and abdomen)
  • Lack of physical activity
  • Family members with type 2 diabetes
  • History of gestational diabetes
  • History of impaired glucose tolerance
  • Race: African American, Hispanic, Native American, Asian American, or Pacific Islander
  • Endocrine disorders ( Cushing’s syndrome , hyperthyroidism , acromegaly , polycystic ovary syndrome , pheochromocytoma, glucagonoma)
  • Medications (pentamidine, nicotinic acid, glucocorticoids, thiazide)
  • Genetic factors

Symptoms

Type 2 diabetes may not produce symptoms for years.

Symptoms in type 2 diabetes may be due to either high blood sugar or diabetic complications. These symptoms may include the following:

  • Weight loss
  • Increased urination
  • Extreme thirst
  • Hunger
  • Fatigue
  • Blurry vision
  • Irritability
  • Frequent or recurring infections
  • Poor wound healing
  • Angina
  • Painful leg cramps when walking
  • Numbness or tingling in the hands or feet
  • In women: frequent vaginal yeast infections
  • Problems with gums
  • Itching
  • Impotence

Diagnosis

The doctor will ask about your symptoms and medical and family history, and perform a physical exam.

Diagnosis is based on the results of blood tests and other criteria, including:

  • Symptoms of diabetes and a random blood test revealing a blood sugar level greater than or equal to 200 milligrams per deciliter of blood (mg/dL)
  • Blood sugar tests after you have not eaten for eight or more hours revealing blood sugar levels greater than or equal to 126 mg/dL on two different days
  • A glucose tolerance test measuring blood sugar two hours after you consume glucose with a measurement greater than or equal to 200 mg/dL

Based on a 12-month study, researchers found that group education may help people recently diagnosed with type 2 diabetes reach their goals in losing weight and quitting smoking, but not in controlling their blood sugar levels. * 8

Treatment

Diabetes treatment aims to maintain blood sugar at levels as close to normal as possible. Regular medical care is essential for preventing or delaying complications.

In a recent study, patients who received brief counseling during their regular doctor's appointments reported an increase in physical activity, but no difference in weight loss. * 9

Diet

  • Follow a balanced meal plan, eating consistent and moderate amounts of food at regular times.
  • Do not skip meals.
  • Eat plenty of fruits, vegetables, and fiber.
  • Eat limited amounts of fat.
  • Eat moderate amounts of protein and low-fat dairy products.
  • Carefully limit foods containing sugar, which may be included as part of a balanced diet plan.
  • Eat a bedtime snack with protein and a starchy food.
  • Keep a record of your food intake to help a dietitian or doctor advise you based on your nutritional needs.

Weight Loss

If you are overweight, talk to your doctor about a reasonable weight goal and a safe diet program.

Exercise

Physical activity helps the body use blood sugar. It will also help you reach and maintain a healthy weight, and lower the levels of fat in your blood. Follow your doctor's recommendations for activity levels and restrictions. In a recent review, exercise was found to improve blood sugar control in patients with type 2 diabetes. * 2

Oral Medication

Medications taken by mouth may be used to lower blood sugar. These may include:

  • Drugs that prompt the beta cells in the pancreas to make more insulin (eg, sulfonylureas [glyburide, tolazamide])
  • Insulin sensitizers—a class of drugs that help the body better use insulin (eg, rosiglitazone and pioglitazone)
    • See paragraph below on rosiglitazone.
  • Starch blockers—a class of drugs (eg, acarbose and miglitol) that helps decrease the absorption of glucose into the bloodstream (through the intestine), resulting in better blood sugar control (a blunted increase) after a meal
  • Drugs that help reduce the production of glucose by the liver (eg, metformin)
  • Amylin analogues (eg, pramlintide)
  • Dipeptidyl peptidase IV (DDPP-4) inhibitor (eg, sitagliptin)
  • Incretin-mimetic (eg, exenatide)

An analysis of 42 trials showed that patients with diabetes or prediabetes who took rosiglitazone (Avandamet) were 43% more likely to have a heart attack compared to those who did not take the medication. Talk to your doctor if you are taking rosiglitazone. * 3

A study involving intensive blood sugar goals for patients with type 2 diabetes was stopped due to increased mortality for those receiving the treatment. Researchers have not yet determined a specific cause for the increased deaths. * 6 In contrast, preliminary evidence from another trial shows no increased mortality with intensive treatment to lower blood glucose. Analyses are still being conducted for both trials. * 7

Insulin

Insulin by injection supplement the insulin produced by the body. Insulin therapy is needed when blood sugar levels are not kept low enough with diet, exercise, and oral medications, usually in advanced cases.

Blood Sugar Testing

Checking blood sugar levels during the day (fasting and 2 hours after meals) helps you and your doctor track the amount of glucose in your blood and determine if the dose or the type of antidiabetic treatment needs to be adjusted. Testing is easy with a blood glucose monitor. Keeping track of blood glucose levels is particularly important if you take insulin.

However, many patients with type 2 diabetes can be adequately managed by using another test called glycosylated hemoglobin or hemoglobin A1c (HbA1c), which is performed in a doctor’s office. Unlike blood sugar levels, HbA1c has the advantage of measuring average blood glucose levels over the previous three-month period, which marks the effectiveness of diabetes management over the long-term. Most diabetics are recommended to keep their HBA1c levels below 7 mg/dl.

A study suggests that regular blood sugar testing may not be necessary in patients with type 2 diabetes whose condition is under reasonably good control without insulin. * 4 However, talk with your doctor before stopping blood sugar monitoring.

Alternative Therapies

Researchers studies vitamin E supplementation in a particular group of patients—those with type 2 diabetes mellitus and a certain genotype (called Haptoglobin 2-2). Vitamin E was associated with a decrease in the rates of cardiovascular events. * 5

Prevention

Regular physical activity and maintaining a healthy weight can reduce your chance of developing type 2 diabetes. In a trial of patients who were overweight and had prediabetes, lifestyle changes reduced the incidence of diabetes for up to seven years. * 1

Although lifestyle changes appear to be more effective than medications in individuals with glucose intolerance, ask your doctor if taking a drug, such as metformin or rosiglitazone, may help reduce your risk of developing type 2 diabetes.