Type 2 diabetes is a chronic (lifelong) disease marked by high levels of sugar in the blood. It begins when the body does not respond correctly to insulin, a hormone released by the pancreas. Type 2 diabetes is the most common form of diabetes.

See also:

• Diabetes
• Gestational diabetes
• Type 1 diabetes

Diabetes is caused by a problem in the way your body makes or uses insulin. Insulin is needed to move glucose (blood sugar) into cells, where it is used for energy.

If glucose does not get into the cells, the body cannot use it for energy. Too much glucose will stay in the blood, causing the symptoms of diabetes.

There are several types of diabetes. This article focuses on type 2, which usually occurs with obesity and insulin resistance.

Insulin resistance means that fat, liver and muscle cells do not respond normally to insulin. As a result they do not store sugar for energy. Since the tissues do not respond well to insulin, the pancreas produces more and more insulin.

Because sugar is not getting into the tissues, abnormally high levels of sugar build up in the blood. This is called hyperglycemia. Many people with insulin resistance have hyperglycemia and high blood insulin levels at the same time. People who are overweight have a higher risk of insulin resistance, because fat interferes with the body's ability to use insulin.

Type 2 diabetes usually occurs gradually. Most people with the disease are overweight at the time of diagnosis. However, type 2 diabetes can also develop in those who are thin, especially the elderly.

Family history and genetics play a large role in type 2 diabetes. Low activity level, poor diet, and excess body weight (especially around the waist) significantly increase your risk for type 2 diabetes.

Other risk factors include:

• Age greater than 45 years
• HDL cholesterol of less than 35 mg/dL or triglyceride level of greater than 250 mg/dL
• High blood pressure
• History of gestational diabetes
• Previously identified impaired glucose tolerance by your doctor
• Race/ethnicity (African Americans, Hispanic Americans, and Native Americans all have high rates of diabetes)

Often, people with type 2 diabetes have no symptoms at all. If you do have symptoms, they may include:

• Blurred vision
• Erectile dysfunction
• Fatigue
• Frequent or slow-healing infections
• Increased appetite
• Increased thirst
• Increased urination

Type 2 diabetes is diagnosed with the following blood tests:

• Fasting blood glucose level -- diabetes is diagnosed if higher than 126 mg/dL on 2 occasions.
• Oral glucose tolerance test -- diabetes is diagnosed if glucose level is higher than 200 mg/dL after 2 hours.
• Random (non-fasting) blood glucose level -- diabetes is suspected if higher than 200 mg/dL and accompanied by the classic symptoms of increased thirst, urination, and fatigue (this test must be confirmed with a fasting blood glucose test).

Have your hemoglobin A1c (HbA1c) level checked every 3 - 6 months. The HbA1c is a measure of average blood glucose during the past 2 -3 months. It is a very helpful way to determine how well treatment is working.

The immediate goal of treatment is to lower high blood glucose levels. The long-term goals of treatment are to prevent diabetes-related complications, such as:

• Amputation of limbs
• Blindness
• Heart disease
• Kidney failure

The primary treatment for type 2 diabetes is exercise and diet.

LEARN THESE SKILLS

You should learn basic diabetes management skills. They will help prevent complications and the need for medical care. These skills include:

• How to test and record your blood glucose (See: blood glucose monitoring)
• What to eat and when
• How to take medications, if needed
• How to recognize and treat low and high blood sugar
• How to handle sick days
• Where to buy diabetes supplies and how to store them

It may take several months to learn the basic skills. Always continue to educate yourself about the disease and its complications. Learn how to control and live with diabetes. Over time, stay current on new research and treatment.

SELF-TESTING

Regular self-testing of your blood sugar tells you how well your combination of diet, exercise, and medication are working. Tests are usually done before meals and at bedtime. More frequent testing may be needed when you are sick or under stress.

A device called a glucometer can provide an exact blood sugar reading. There are different types of devices. Usually, you prick your finger with a small needle called a lancet. This gives you a tiny drop of blood. You place the blood on a test strip and put the strip into the device. Results are available in 30 - 45 seconds.

A health care provider or diabetes educator will help set up an appropriate testing schedule for you. You will also be taught how to respond to different ranges of glucose values when you self-test.

The results of the test can be used to adjust meals, activity, or medications to keep your blood sugar levels in an appropriate range. Testing provides valuable information for the health care provider. It can identify high and low blood sugar levels before serious problems develop.

Keeping accurate records of test results will help you and your health care provide plan how to best control your diabetes.

DIET AND WEIGHT CONTROL

Meal planning includes choosing healthy foods, eating the right amount of food, and eating meals at the right time. You should work closely with your health care provider to learn how much fat, protein, and carbohydrates you need in your diet. Your specific meal plans need to be tailored to your food habits and preferences.

Managing your weight and eating a well-balanced diet are important. Some people with type 2 diabetes can stop taking medications after losing weight (although the diabetes is still there). A registered dietitian can help determine your dietary needs. (See diabetes diet)

REGULAR PHYSICAL ACTIVITY

Regular exercise is important for everyone, but especially if you have diabetes. Regular exercise helps control the amount of glucose in the blood. It also helps burn excess calories and fat so you can manage your weight.

Exercise can help your overall health by improving blood flow and blood pressure. It decreases insulin resistance even without weight loss. Exercise also increases the body's energy level, lowers tension, and improves your ability to handle stress.

Consider the following when starting an exercise routine:

• Always check with your health care provider before starting an exercise program.
• Ask your health care provider whether you have the right footwear.
• Choose an enjoyable physical activity that is appropriate for your current fitness level.
• Exercise every day, and at the same time of day, if possible.
• Monitor blood glucose levels at home before and after exercise.
• Carry food that contains a fast-acting carbohydrate in case blood glucose levels get too low during or after exercise.
• Wear a diabetes identification bracelet and carry a cell phone in case of emergency.
• Drink extra fluids that do not contain sugar before, during, and after exercise.
• You may need to modify your diet or medication if you exercise longer or more intensely, to keep blood glucose levels in the correct range.

MEDICATION

When diet and exercise do not help maintain normal or near-normal blood glucose levels, your doctor may prescribe medication. Most people with type 2 diabetes will eventually need more than one medication to maintain good blood sugar control. Different groups of medications may be combined or used with insulin.

Some of the most common types of medication are listed below. They are taken by mouth or injection.

• Alpha-glucosidase inhibitors (such as acarbose) decrease the absorption of carbohydrates from the digestive tract to lower after-meal glucose levels.
• Biguanides (Metformin) tell the liver to decrease its production of glucose. This decreases glucose levels in the bloodstream.
• Injectible medications (including exenatide and pramlintide) can lower blood sugar.
• Meglitinides (including repaglinide and nateglinide) trigger the pancreas to make more insulin in response to the level of glucose in the blood.
• Oral sulfonylureas (like glimepiride, glyburide, and tolazamide) trigger the pancreas to make more insulin.
• Thiazolidinediones (such as rosiglitazone) help insulin work better at the cell site. They increase the cell's sensitivity (responsiveness) to insulin. Rosiglitazone may increase the risk of heart problems. Talk to your doctor.

If you continue to have poor blood glucose control despite lifestyle changes and taking medicines by mouth, your doctor will prescribe insulin. Insulin may also be prescribed if you have had a bad reaction to other medicines. Insulin must be injected under the skin using a syringe. It cannot be taken by mouth.

Insulin preparations differ in how fast they start to work and how long they work. Your healthcare provider will determine the appropriate type of insulin to use and will tell you what time of day to use it.

More than one type may be mixed together in an injection to achieve the best blood glucose control. Usually injections are needed one to four times a day. Your doctor or diabetes educator will show you how to give yourself an injection.

Some people with type 2 diabetes find they no longer need medication if they lose weight and increase activity. When they reach their ideal weight, their own insulin and a careful diet can control their blood glucose levels.

It is not known whether hypoglycemia medications taken by mouth are safe for use in pregnancy. Women who have type 2 diabetes and take these medications may be switched to insulin during pregnancy and while breastfeeding.

FOOT CARE

People with diabetes are more likely to have foot problems. Diabetes can damage nerves, which means you may not feel an injury to the foot until a large sore or infection develops. Diabetes can also damage blood vessels.

In addition, diabetes affects the body's immune system. This decreases the body's ability to fight infection. Small infections can quickly get worse and cause the death of skin and other tissues. Amputation may be needed.

To prevent injury to the feet, check and care for your feet every day.

See also: Diabetes foot care

CONTINUING CARE

A person with type 2 diabetes should visit a diabetes care provider every 3 months. A complete examination includes:

• Blood pressure check
• Foot and skin examination
• Glycosylated hemoglobin (HbA1c)
• Neurological examination
• Ophthalmoscopy examination

The following evaluations should be done at least once a year:

• BUN and serum creatinine
• Dilated retinal exam
• ECG
• Random microalbumin (urine test for protein)
• Serum cholesterol, HDL, and triglycerides

For additional information, see diabetes resources.

The risk of long-term complications from diabetes can be reduced. If you control your blood glucose and blood pressure, you can reduce your risk of death, stroke, heart failure, and other complications. Reduction of HbA1c by even 1% can decrease your risk for complications by 25%.

Emergency complications include diabetic coma.

Long-term complications include:

• Atherosclerosis
• Coronary artery disease
• Diabetic nephropathy (kidney disease)
• Diabetic neuropathy (nerve damage)
• Diabetic retinopathy (eye disease)
• Erection problems
• High blood pressure
• High cholesterol
• Infections of the skin, female genital tract, and urinary tract
• Peripheral vascular disease (damage to blood vessels/circulation)
• Stroke

Call your health care provider immediately if you have:

• Confusion
• Dizziness
• Double vision
• Drowsiness
• Headache
• Lack of coordination
• Trembling
• Weakness

These symptoms can quickly get worse and become emergency conditions (such as convulsions, unconsciousness, or hypoglycemic coma).

Screening for type 2 diabetes and people with no symptoms is recommended for:

• Overweight children who have other risk factors for diabetes, starting at age 10 and repeating every 2 years
• Overweight adults (BMI greater than 25) who have other risk factors
• Adults over 45, repeated every 3 years

Maintain a healthy body weight and keep an active lifestyle to help prevent type 2 diabetes.

To prevent complications of diabetes, visit your health care provider or diabetes educator at least four times a year. Talk about any problems you are having.

Regularly have the following tests:

• Have your blood pressure checked every year (blood pressure goals should be 130/80 mm/Hg or lower).
• Have your glycosulated hemoglobin (HbA1c) checked every 6 months if your diabetes is well controlled, otherwise every 3 months.
• Have your cholesterol and triglyceride levels checked yearly (aim for LDL levels below 100 mg/dL).
• Get yearly tests to make sure your kidneys are working well (microalbuminuria and serum creatinine).
• Visit your ophthalmologist (preferably one who specializes in diabetic retinopathy) at least once a year, or more often if you have signs of diabetic retinopathy.
• See the dentist every 6 months for a thorough dental cleaning and exam. Make sure your dentist and hygienist know that you have diabetes.
• Make sure your health care provider inspects your feet at each visit.

Stay up-to-date with all of your vaccinations and get a flu shot every year in the fall.

American Diabetes Association. Standards of medical care in diabetes -- 2008. Diabetes Care. 2008/31:S12-S54.

American Diabetes Association (ADA). Standards of medical care in diabetes IV. Prevention/delay of type 2 diabetes. Diabetes Care. 2007;30:S7-S8.

In the clinic. Type 2 diabetes. Ann Intern Med. 2007;146:ITC-1-15.

Psaty BM, Furberg CD. Rosiglitazone and Cardiovascular Risk. N Engl J Med. 2007 May 21; [Epub ahead of print].