Diabetes Mellitus: An Overview
What is diabetes mellitus?
Diabetes mellitus (commonly referred to as diabetes) is a disease of the pancreas, an organ behind your stomach that produces the hormone insulin. Insulin helps the body use food for energy. When a person has diabetes, the pancreas either cannot produce enough insulin, uses the insulin incorrectly, or both. Insulin works together with glucose (sugar) in the bloodstream to help it enter the body's cells to be burned for energy. If the insulin isn't functioning properly, glucose cannot enter the cells. This causes glucose levels in the blood to rise, creating a condition of high blood sugar or diabetes, and leaving the cells without fuel.
What are the common types of diabetes?
There are two common forms of diabetes: type 1 and type 2.
- Type 1: Type 1 diabetes occurs because the insulin-producing cells of the pancreas (beta cells) are damaged. In type 1 diabetes, the pancreas makes little or no insulin, so sugar cannot get into the body's cells for use as energy. People with type 1 diabetes must use insulin injections to control their blood glucose. Type 1 is the most common form of diabetes in people under age 20-30, but it can occur at any age. Ten percent of people with diabetes are diagnosed with type 1.
- Type 2: In type 2 diabetes, the pancreas makes insulin, but it either doesn't produce enough insulin or the insulin does not work properly. Type 2 diabetes may sometimes be controlled with a combination of diet, weight management and exercise. However, treatment also may include oral glucose-lowering medications or insulin injections.
Generally, type 2 diabetes is more common in people over age 40 who are overweight. However, the prevalence of obesity among people in North America has increased the number of people under age 40 who are diagnosed with type 2 diabetes. Nine out of 10 people with diabetes have type 2.
What causes diabetes?
Health care providers do not yet know what causes diabetes. The following factors may increase your chance of getting diabetes:
- Family history of diabetes or inherited tendency
- African-American, Hispanic, Native American or Asian-American race or ethnic background
- Being overweight (20 percent or more over your desired body weight)
- Physical stress (such as surgery or illness)
- Use of certain medications, including steroid and blood pressure medications
- Injury to pancreas (such as infection, tumor, surgery or accident)
- Autoimmune disease
- High blood pressure
- Abnormal blood cholesterol or triglyceride levels
- Age (risk increases with age)
- Alcohol (risk increases with years of heavy alcohol use)
- Pregnancy (see “What is gestational diabetes?” on the last page)
It is important to note that sugar itself does not cause diabetes. Eating a lot of sugar can lead to tooth decay, but it does not cause diabetes.
How is diabetes diagnosed?
The preferred method of diagnosing diabetes is the fasting plasma glucose test (FPG). The FPG measures your blood glucose level after you have fasted (not eaten anything) for 10 to 12 hours.
Normal fasting blood glucose is between 70 and 100 mg/dl for people who do not have diabetes. The standard diagnoses of diabetes is made when:
- A patient has a fasting blood glucose level of 126 mg/dl or higher on two separate occasions; or
- A patient has a random blood glucose level of 200 mg/dl or greater and has common symptoms of diabetes, such as:
- On occasion, an oral glucose tolerance test may aid in the diagnosis of diabetes or an earlier abnormality that may become diabetes - called impaired glucose tolerance.
Another test, the A1C test, measures your average percentage of glycated hemoglobin, or HbA1c, in the blood. This test tells you about your blood glucose control for the past 2 to 3 months. It gives you an idea of how your treatment plan is coming along but does not replace daily testing.
Other symptoms of diabetes may include:
What are some of the long-term complications of diabetes?
Retinopathy (eye disease): All patients with diabetes should see an ophthalmologist (eye specialist) yearly for a dilated eye examination. Patients with known eye disease, symptoms of blurred vision in one eye or who have blind spots may need to see their ophthalmologist more frequently.
Nephropathy (kidney disease): Urine testing should be performed yearly. Regular blood pressure checks also are important because control of high blood pressure is essential in slowing kidney disease. Generally, blood pressure should be maintained less than 130/80 in adults. Persistent leg or feet swelling also may be a symptom of kidney disease and should be reported to your doctor.
Neuropathy (nerve disease): Numbness or tingling in your feet should be reported to your doctor at your regular visits. You should check your feet daily for redness, calluses, cracks or breakdown in skin tissue. If you notice these symptoms before scheduled visits, notify your doctor immediately.
Other long-term may complications include:
- Eye problems including glaucoma and cataracts
- Dental problems
- High blood pressure
- Heart disease
How is diabetes managed?
There is no cure for diabetes, but it can be treated and controlled. The goals of managing diabetes are to:
- Keep your blood glucose levels as near to normal as possible by balancing food intake with medication and activity.
- Maintain your blood cholesterol and triglyceride (lipid) levels as near the normal ranges as possible by decreasing the total amount of fat to 30% or less of your total daily calories and by reducing saturated fat and cholesterol.
- Control your blood pressure. (Your blood pressure should not go over 130/80.)
- Decrease or possibly prevent the development of diabetes-related health problems.
You hold the keys to managing your diabetes by:
- Planning what you eat and following a balanced meal plan
- Exercising regularly
- Taking medication, if prescribed, and closely following the guidelines on how and when to take it
- Monitoring your blood glucose and blood pressure levels at home
- Keeping your appointments with your health care providers and having laboratory tests completed as ordered by your doctor.
What you do at home every day affects your blood glucose more than what your doctor can do every few months during your check-ups.
What is gestational diabetes?
Gestational diabetes occurs when there is a high blood glucose level during pregnancy. As pregnancy progresses, the developing baby has an increased need for glucose. Hormone changes during pregnancy also affect the action of insulin, resulting in high blood glucose levels.
Pregnant women who have an increased risk of developing gestational diabetes include those who:
- Are over 25 years old
- Are above their desired body weight
- Have a family history of diabetes
- Are Hispanic, African-American, Native American or Asian-American
Usually, blood glucose levels return to normal after childbirth. However, women who have had gestational diabetes have an increased risk of developing type 2 diabetes later in life.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 4/2/2013...#7104