What is diabetes?
Diabetes mellitus is a group of diseases characterized by high levels of blood glucose resulting from defects in insulin secretion, insulin action, or both. Diabetes can be associated with serious complications and premature death, but persons with diabetes can take measures to reduce the likelihood of such occurrences.
The four types of diabetes
- Type 1 diabetes was previously called insulin-dependent diabetes mellitus (IDDM) or juvenile-onset diabetes. Type 1 diabetes accounts for 5% to 10% of all diagnosed cases of diabetes. Risk factors are less well defined for type 1 diabetes than for type 2 diabetes, but autoimmune, genetic, and environmental factors are involved in the development of this type of diabetes.
- Type 2 diabetes was previously called non-insulin dependent diabetes mellitus (NIDDM) or adult-onset diabetes. Type 2 diabetes accounts for about 90% to 95% of all diagnosed cases of diabetes. Risk factors for type 2 diabetes include older age, obesity, family history of diabetes, prior history of gestational diabetes, impaired glucose tolerance, physical inactivity, and race/ethnicity.
- Gestational diabetes develops in 2% to 5% of all pregnancies but disappears when a pregnancy is over. Obesity is also associated with higher risk. Women who have had gestational diabetes are at increased risk for later developing type 2 diabetes. In some studies, nearly 40% of women with a history of gestational diabetes developed diabetes in the future.
- "Other specific types" of diabetes result from specific genetic syndromes, surgery, drugs, malnutrition, infections, and other illnesses. Such types of diabetes account for 1% to 2% of all diagnosed cases of diabetes.
Complications of diabetes
Heart disease Heart disease is the leading cause of diabetes-related deaths. Adults with diabetes have heart disease death rates about two to four times as high as that of adults without diabetes.
- Stroke: The risk of stroke is two to four times higher in people with diabetes.
- High blood pressure: An estimated 60% to 65% of people with diabetes have high blood pressure.
- Diabetes is the leading cause of new cases of blindness in adults 20 to 74 years old.
- Diabetic retinopathy causes from 12,000 to 24,000 new cases of blindness each year.
- Kidney disease Diabetes is the leading cause of end-stage renal disease, accounting for about 40% of new cases.
- Nervous system disease
- About 60% to 70% of people with diabetes have mild to severe forms of nervous system damage (which often includes impaired sensation or pain in the feet or hands, slowed digestion of food in the stomach, carpal tunnel syndrome, and other nerve problems).
- Severe forms of diabetic nerve disease are a major contributing cause of lower extremity amputations.
- Amputations: More than half of lower limb amputations in the United States occur among people with diabetes.
- Dental disease: Periodontal disease (a type of gum disease that can lead to tooth loss) occurs with greater frequency and severity among people with diabetes. Periodontal disease has been reported to occur among 30% of people aged 19 years or older with type 1 diabetes.
- Complications of pregnancy: The rate of major congenital malformations in babies born to women with preexisting diabetes varies from 0% to 5% among women who receive preconception care to 10% among women who do not receive preconception care.
- Other complications
- Diabetes can directly cause acute life-threatening events, such as diabetic ketoacidosis* and hyperosmolar nonketotic coma.*
- People with diabetes are more susceptible to many other illnesses. For example, they are more likely to die of pneumonia or influenza than people who do not have diabetes.
Remark: *Diabetic ketoacidosis and hyperosmolar nonketotic coma are medical conditions that can result from very high glucose level and biochemical imbalance in uncontrolled diabetes.
New diagnostic criteria for diabetes*
The new diagnostic criteria for diabetes include the following changes:
- The routine diagnostic test for diabetes is now a fasting plasma glucose test. However, in certain clinical circumstances, physicians may choose to perform oral glucose tolerance test.
- A confirmed** fasting plasma glucose value of greater than or equal to 126 milligrams/deciliter (mg/dL) indicates a diagnosis of diabetes.
- In the presence of symptoms of diabetes, a confirmed** nonfasting plasma glucose value of greater than or equal to 200 mg/dL indicates a diagnosis of diabetes.
- When a doctor chooses to perform an oral glucose tolerance test (by administering 75 grams of glucose dissolved in water, then measuring the plasma glucose concentration 2 hours later), glucose value of greater than or equal to 200 mg/dL indicates a diagnosis of diabetes.
- In pregnant women, different requirements are used to identify the presence of gestational diabetes.
** Except in certain specified circumstances, abnormal tests must be confirmed by repeat testing on another day.
Treatment of diabetes
Diabetes knowledge, treatment, and prevention strategies advance daily. Treatment is aimed at keeping blood glucose near normal levels at all times. Training in self- management is integral to the treatment of diabetes. Treatment must be individualized and must address medical, psychosocial, and lifestyle issues.
- Treatment of type 1 diabetes: Lack of insulin production by the pancreas can make type 1 diabetes difficult to control. Treatment requires a regimen that includes a carefully calculated diet, planned physical activity, home blood glucose testing and multiple daily insulin injections.
- Treatment of type 2 diabetes: Treatment includes diet control, exercise, home blood glucose testing, and in some cases, oral medication and/or insulin. Approximately 40% of people with type 2 diabetes require insulin injections.
Impaired fasting glucose
Impaired fasting glucose is a new diagnostic category in which persons have fasting plasma glucose values of 110-125 mg/dL. These glucose values are greater than the level considered normal but less than the level that is diagnostic of diabetes. Scientists are trying to learn how to predict which of these persons will go on to develop diabetes and how to prevent such progression.
What Is Insulin?
Inside the pancreas, beta cells make the hormone insulin. With each meal, beta cells release insulin to help the body use or store the glucose it gets from food.
In people with type 1 diabetes, the pancreas no longer makes insulin. The beta cells have been destroyed. They need insulin shots to use glucose from meals.
People with type 2 diabetes make insulin, but their bodies don't respond well to it. Some people with type 2 diabetes need diabetes pills or insulin shots to help their bodies use glucose for energy.
Insulin cannot be taken as a pill. It would be broken down during digestion just like the protein in food. Insulin must be injected into the fat under your skin for it to get into your blood.
There are more than 20 types of insulin sold. These insulins differ in how they are made, how they work in the body, and price.
- There are four types of insulin, based on
- How soon the insulin starts working (onset)
- When it works the hardest (peak time)
- How long it lasts in your body (duration)
Pills to treat type 2 diabetes
The first treatment for type 2 diabetes is often meal planning for blood glucose (sugar) control, weight loss, and exercising. But sometimes these measures are not enough to bring blood sugar down near the normal range. The next step is taking a medicine that lowers blood sugar levels. There are two kinds of medicines: oral medications (pills) and insulin shots. Diabetes pills are not insulin.
How They Work
In people with diabetes, blood sugar levels are too high. These high levels occur because glucose remains in the blood rather than entering cells, where it belongs. But for glucose to pass into a cell, insulin must be present, and the cell must be "hungry" for glucose.
- People with type 1 diabetes don't make insulin. For them, insulin shots are the only way to keep blood sugar levels down.
- People with type 2 diabetes tend to have two problems. They don't make quite enough insulin, and the cells of their bodies don't seem to take in glucose as eagerly as they should.
All diabetes pills sold today are members of three classes of drugs. They work in different ways to lower blood sugar.
The first class of drugs stimulates the beta cells to release more insulin.
- Sulfonylurea drugs have been in use since the 1950s. These drugs are generally taken one to two times a day, before meals. All sulfonylurea drugs have similar effects on blood sugar levels, but they differ in side effects, how often they are taken, and interactions with other drugs.
- Repaglinide is a short acting drug. It is taken three times per day before meals. Because this class of drugs stimulates the release of insulin, it is possible to cause hypoglysemia (low blood sugar).
The second class of diabetes drugs sensitizes the body to the insulin that is already present.
- Metformin is a biguanide. It lowers blood sugar by helping insulin work better, mostly in the liver. It is usually taken two or three times a day. A side effect of metformin includes bloating which usually improves once you take the medication for one or two weeks.
- The glitazones, rosiglitazone, and pioglitazone, form a group of drugs called thiazolidinediones. They help insulin work better in the muscle and fat. litazones can cause fluid retention, please consult your physician if you experience signs or symptoms of fluid retention.
The third class of oral drugs slows or blocks the breakdown of starches and certain sugars.
- Acarbose and meglitol are alpha-glucosidase inhibitors. They help the body lower blood sugar by blocking the breakdown of starches, such as bread, potatoes, and pasta. They also slow the breakdown of some sugars, such as table sugar. Their action slows the rise in blood sugar levels after a meal. They should be taken with the first bite of a meal. These drugs may have side effects, including gas and diarrhea.
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