Diabetes (Type 1, 2, and Gestational)

What is type 1 diabetes?

Type 1 diabetes may also be known by a variety of other names, including the following:

• Insulin-dependent diabetes mellitus (IDDM)

• Juvenile diabetes

• Brittle diabetes

• Sugar diabetes

There are two forms of type 1 diabetes:

• Idiopathic type 1 diabetes. This refers to rare forms of the disease with no known cause.

• Immune-mediated diabetes. An autoimmune disorder in which the body's immune system destroys, or attempts to destroy, the cells in the pancreas that produce insulin.

Immune-mediated diabetes is the most common form of type 1 diabetes, and the one generally referred to as type 1 diabetes. The information on this page refers to this form of type 1 diabetes.

Type 1 diabetes accounts for 5 to 10 percent of all diagnosed cases of diabetes in the U.S. Type 1 diabetes usually develops in children or young adults, but can start at any age.

What causes type 1 diabetes?

The cause of type 1 diabetes is unknown, but it is believed that genetic and environmental factors (possibly viruses) may be involved. The body's immune system attacks and destroys the insulin producing cells in the pancreas. Insulin allows glucose to enter the cells of the body to provide energy.

When glucose cannot enter the cells, it builds up in the blood, depriving the cells of nutrition. People with type 1 diabetes must take daily insulin injections and regularly monitor their blood sugar levels.

What are the symptoms of type 1 diabetes?

Type 1 diabetes often appears suddenly. The following are the most common symptoms of type 1 diabetes. However, each individual may experience symptoms differently. Symptoms may include:

• High levels of sugar in the blood when tested

• High levels of sugar in the urine when tested

• Unusual thirst

• Frequent urination

• Extreme hunger but loss of weight

• Blurred vision

• Nausea and vomiting

• Extreme weakness and fatigue

• Irritability and mood changes

In children, symptoms may be similar to those of having the flu.

The symptoms of type 1 diabetes may resemble other conditions or medical problems. Always consult your physician for a diagnosis.

What complications may be associated with type 1 diabetes?

Type 1 diabetes can cause many different problems. However, the three key complications of diabetes include the following:

1. Hypoglycemia. Low blood sugar; sometimes called an insulin reaction; occurs when blood sugar drops too low.

2. Hyperglycemia. High blood sugar; occurs when blood sugar is too high, and can be a sign that diabetes is not well-controlled.

3. Ketoacidosis. High blood sugar and a build up of acids in the blood due to untreated or under-treated diabetes.

Treatment for type 1 diabetes

Specific treatment for type 1 diabetes will be determined by your physician based on:

• Your age, overall health, and medical history

• Extent of the disease

• Your tolerance for specific medications, procedures, or therapies

• Expectations for the course of the disease

• Your opinion or preference

People with type 1 diabetes must have daily injections of insulin to keep their blood sugar level within normal ranges. Other parts of the treatment protocol may include:

• Appropriate diet (to manage blood sugar levels)

• Exercise (to lower and help the body use blood sugar)

• Careful self-monitoring of blood sugar levels several times a day, as directed by your physician

• Careful self-monitoring of ketone levels in the urine several times a day, as directed by your physician

• Regular monitoring of the hemoglobin A1c levels

The hemoglobin A1c test (also called HbA1c test) shows the average amount of sugar in the blood over the last three months. The result will indicate if the blood sugar level is under control. The frequency of HbA1c testing will be determined by your physician. It is recommended that testing occur at least twice a year if the blood sugar level is in the target range and stable, and more frequently if the blood sugar level is unstable.

Advances in diabetes research have led to improved methods of managing diabetes and treating its complications. However, scientists continue to explore the causes of diabetes and ways to prevent and treat the disorder. Other methods of administering insulin through inhalers and pills are currently being studied. Scientists are investigating gene involvement in type 1 and type 2 diabetes, and some genetic markers for type 1 diabetes have been identified. Pancreas and islet cell transplants are also being performed.

What is type 2 diabetes?

Type 2 diabetes is a metabolic disorder resulting from the body's inability to make enough, or to properly use, insulin. It used to be called non-insulin-dependent diabetes mellitus (NIDDM).

Without adequate production or utilization of insulin, the body cannot move blood sugar into the cells. It is a chronic disease that has no known cure. It is the most common type of diabetes, accounting for about 95 percent of diabetes cases.

What is prediabetes?

Type 2 diabetes is commonly preceded by prediabetes. In prediabetes, blood glucose levels are higher than normal but not high enough to be defined as diabetes. However, many people with prediabetes develop type 2 diabetes within 10 years, states the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Prediabetes also increases the risk of heart disease and stroke. With modest weight loss and moderate physical activity, people with prediabetes can delay or prevent type 2 diabetes.

Prediabetes affects 79 million people in the US, according to the American Diabetes Association (ADA).

What causes type 2 diabetes?

The exact cause of type 2 diabetes is unknown. However, there does appear to be a genetic factor which causes it to run in families. And, although a person can inherit a tendency to develop type 2 diabetes, it usually takes another factor, such as obesity, to bring on the disease.

Prevention or delay of onset of type 2 diabetes:

Type 2 diabetes may be prevented or delayed by following a program to eliminate or reduce risk factors - particularly losing weight and increasing exercise. Information gathered by the Diabetes Prevention Program, sponsored by the National Institutes of Health and the American Diabetes Association, continues to study this possibility.

What are the symptoms of type 2 diabetes?

The following are the most common symptoms of type 2 diabetes. However, each individual may experience symptoms differently. Symptoms may include:

• Frequent infections that are not easily healed

• High levels of sugar in the blood when tested

• High levels of sugar in the urine when tested

• Unusual thirst

• Frequent urination

• Extreme hunger but loss of weight

• Blurred vision

• Nausea and vomiting

• Extreme weakness and fatigue

• Irritability and mood changes

• Dry, itchy skin

• Tingling or loss of feeling in the hands or feet

Some people who have type 2 diabetes exhibit no symptoms. Symptoms may be mild and almost unnoticeable, or easy to confuse with signs of aging. Half of all Americans who have diabetes do not know it.

The symptoms of type 2 diabetes may resemble other conditions or medical problems. Always consult your physician for a diagnosis.

What are the risk factors for type 2 diabetes?

Risk factors for type 2 diabetes include the following:

• Age. People over the age of 45 are at higher risk for diabetes.

• Family history of diabetes. 

• Being overweight.

• Not exercising regularly.

• Race and ethnicity. Being a member of certain racial and ethnic groups, such as African-Americans, Hispanic Americans, and American Indians increases the risk for type 2 diabetes.

• Pregnancy.

• History of gestational diabetes, or giving birth to a baby who weighed more than 9 pounds.

• A low level HDL (high-density lipoprotein - the "good cholesterol").

• A high triglyceride level.

Treatment for type 2 diabetes:

Specific treatment for type 2 diabetes will be determined by your physician based on:

• Your age, overall health, and medical history

• Extent of the disease

• Your tolerance for specific medications, procedures, or therapies

• Expectations for the course of the disease

• Your opinion or preference

The goal of treatment is to keep blood sugar levels as close to normal as possible. Emphasis is on control of blood sugar (glucose) by monitoring the levels, regular physical activity, meal planning, and routine health care. Treatment of diabetes is an ongoing process of management and education that includes not only the person with diabetes, but also health care professionals and family members.

Often, type 2 diabetes can be controlled through losing weight, improved nutrition, and exercise alone. However, in some cases, these measures are not enough and either oral or injected medications and/or insulin must be used. Treatment often includes:

• Proper diet.

• Weight control.

• An appropriate exercise program.

• Regular foot inspections.

• Oral medications, other medications, and/or insulin replacement therapy, as directed by your physician. There are various types of medications that may be used to treat type 2 diabetes when lifestyle changes such as diet, exercise, and weight loss are not effective. Oral medications of several different types are available, with each type working in a different manner to lower blood sugar. One medication may be combined with another one to improve blood sugar control. When oral medications are no longer effective, insulin may be required. New medications for treating diabetes are in development. GLP-1 agonists are one of the new types of medications. GLP-1 agonists work by stimulating insulin production by the pancreas, slowing the emptying of food from the stomach, and inhibiting the production of glucagon in the pancreas (glucagon is a hormone produced by the pancreas that stimulates release of glucose by the liver). Byetta®, a GLP-1 agonist approved by the FDA in 2005, is given by injection.

• Regular monitoring of the hemoglobin A1c levels. The hemoglobin A1c test (also called HbA1c test) shows the average amount of sugar in the blood over the last three months. The result will indicate if the blood sugar level is under control. The frequency of HbA1c testing will be determined by your physician. It is recommended that testing occur at least twice a year if the blood sugar level is in the target range and stable, and more frequently if the blood sugar level is unstable.

Untreated or inappropriately-treated diabetes can cause problems with the kidneys, legs, feet, eyes, heart, nerves, and blood flow, which could lead to kidney failure, gangrene, amputation, blindness, or stroke. For these reasons, it is important to follow a strict treatment plan.

What is gestational diabetes?

Gestational diabetes is a condition in which the glucose level is elevated and other diabetic symptoms appear during pregnancy in a woman who has not previously been diagnosed with diabetes. All diabetic symptoms disappear following delivery.

Unlike type 1 diabetes, gestational diabetes is not caused by a lack of insulin, but by blocking effects of other hormones on the insulin that is produced, a condition referred to as insulin resistance.

According to the ADA, approximately 4 to 8 percent of all pregnant women in the United States are diagnosed with gestational diabetes.

What causes gestational diabetes mellitus (GDM)?

Although the cause of GDM is not known, there are some theories as to why the condition occurs.

The placenta supplies a growing fetus with nutrients and water, as well as produces a variety of hormones to maintain the pregnancy. Some of these hormones (estrogen, cortisol, and human placental lactogen) can have a blocking effect on insulin. This is called contra-insulin effect, which usually begins about 20 to 24 weeks into the pregnancy.

As the placenta grows, more of these hormones are produced, and insulin resistance becomes greater. Normally, the pancreas is able to make additional insulin to overcome insulin resistance, but when the production of insulin is not enough to overcome the effect of the placental hormones, gestational diabetes results.

What are the risks factors associated with GDM?

Although any woman can develop GDM during pregnancy, some of the factors that may increase the risk include the following:

• Overweight or obesity

• Family history of diabetes

• Having given birth previously to a very large infant, a still birth, or a child with a birth defect

• Age (women who are age 25 or older are at a greater risk for developing gestational diabetes than younger women)

• Race (women who are African- American, American Indian, Asian-American, Hispanic, or Pacific Islander have a higher risk.

• Prediabetes

Although increased glucose in the urine is often included in the list of risk factors, it is not believed to be a reliable indicator for GDM.

How is gestational diabetes mellitus diagnosed?

New Standards of Medical Care in Diabetes-2011 from the American Diabetes Association (ADA) recommend screening for undiagnosed type 2 diabetes at the first prenatal visit in women with diabetes risk factors. In pregnant women not known to have diabetes, GDM testing should be performed at 24 to 28 weeks of gestation.

In addition, women with diagnosed GDM should be screened for persistent diabetes six to 12 weeks postpartum. Women with a history of GDM are now recommended to have life-long screening for the development of diabetes or prediabetes at least every three years.

Treatment for gestational diabetes

Specific treatment for gestational diabetes will be determined by your physician based on:

• Your age, overall health, and medical history

• Extent of the disease

• Your tolerance for specific medications, procedures, or therapies

• Expectations for the course of the disease

• Your opinion or preference

Treatment for gestational diabetes focuses on keeping blood glucose levels in the normal range. Treatment may include:

• Special diet

• Exercise

• Daily blood glucose monitoring

• Insulin injections

Possible complications for the baby:

Unlike type 1 diabetes, gestational diabetes generally does not cause birth defects. Birth defects usually originate sometime during the first trimester (before the 13th week) of pregnancy. But, the insulin resistance from the contra-insulin hormones produced by the placenta does not usually occur until approximately the 24th week. Women with gestational diabetes generally have normal blood sugar levels during the critical first trimester.

The complications of gestational diabetes are usually manageable and preventable. The key to prevention is careful control of blood sugar levels just as soon as the diagnosis of gestational diabetes is made.

Infants of mothers with gestational diabetes are vulnerable to several chemical imbalances, such as low serum calcium and low serum magnesium levels, but, in general, there are two major problems of gestational diabetes: macrosomia and hypoglycemia.

• Macrosomia. Macrosomia refers to a baby that is considerably larger than normal. All of the nutrients the fetus receives come directly from the mother's blood. If the maternal blood has too much glucose, the pancreas of the fetus senses the high glucose levels and produces more insulin in an attempt to use this glucose. The fetus converts the extra glucose to fat. Even when the mother has gestational diabetes, the fetus is able to produce all the insulin it needs. The combination of high blood glucose levels from the mother and high insulin levels in the fetus results in large deposits of fat which causes the fetus to grow excessively large.

• Hypoglycemia. Hypoglycemia refers to low blood sugar in the baby immediately after delivery. This problem occurs if the mother's blood sugar levels have been consistently high, causing the fetus to have a high level of insulin in its circulation. After delivery, the baby continues to have a high insulin level, but it no longer has the high level of sugar from its mother, resulting in the newborn's blood sugar level becoming very low. The baby's blood sugar level is checked after birth, and if the level is too low, it may be necessary to give the baby glucose intravenously.