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Health Information
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Friday, July 04, 2008
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Diabetes Overview
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Almost every
one of us knows someone who has diabetes. An estimated 16
million people in the United States have diabetes mellitus--a
serious, lifelong condition. About half of these people
do not know they have diabetes and are not under care for
the disorder. Each year, about 798,000 people are diagnosed
with diabetes.
Although diabetes
occurs most often in older adults, it is one of the most
common chronic disorders in children in the United States.
About 123,000 children and teenagers age 19 and younger
have diabetes.
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Diabetes
is a disorder of metabolism--the way our bodies use digested
food for growth and energy. Most of the food we eat is broken
down by the digestive juices into a simple sugar called
glucose. Glucose is the main source of fuel for the body.
After digestion,
the glucose passes into our bloodstream where it is available
for body cells to use for growth and energy. For the glucose
to get into the cells, insulin must be present. Insulin
is a hormone produced by the pancreas, a large gland behind
the stomach.
When we eat,
the pancreas is supposed to automatically produce the
right amount of insulin to move the glucose from our blood
into our cells. In people with diabetes, however, the
pancreas either produces little or no insulin, or the
body cells do not respond to the insulin that is produced.
As a result, glucose builds up in the blood, overflows
into the urine, and passes out of the body. Thus, the
body loses its main source of fuel even though the blood
contains large amounts of glucose.
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The
three main types of diabetes are
- Type 1 diabetes
- Type 2 diabetes
- Gestational
diabetes.
Type 1 diabetes
Type 1 diabetes
(once known as insulin-dependent diabetes mellitus or juvenile
diabetes) is considered an autoimmune disease. An autoimmune
disease results when the body's system for fighting infection
(the immune system) turns against a part of the body. In
diabetes, the immune system attacks the insulin-producing
beta cells in the pancreas and destroys them. The pancreas
then produces little or no insulin.
Someone with
type 1 diabetes needs daily injections of insulin to live.
At present, scientists do not know exactly what causes
the body's immune system to attack the beta cells, but
they believe that both genetic factors and viruses are
involved. Type 1 diabetes accounts for about 5 to 10 percent
of diagnosed diabetes in the United States.
Type 1 diabetes
develops most often in children and young adults, but
the disorder can appear at any age. Symptoms of type 1
diabetes usually develop over a short period, although
beta cell destruction can begin years earlier.
Symptoms include
increased thirst and urination, constant hunger, weight
loss, blurred vision, and extreme tiredness. If not diagnosed
and treated with insulin, a person can lapse into a life-threatening
coma.
Type 2 diabetes
The most common
form of diabetes is type 2 diabetes (once known as noninsulin-dependent
diabetes mellitus or NIDDM). About 90 to 95 percent of people
with diabetes have type 2 diabetes. This form of diabetes
usually develops in adults over the age of 40 and is most
common among adults over age 55. About 80 percent of people
with type 2 diabetes are overweight.
In type 2 diabetes,
the pancreas usually produces insulin, but for some reason,
the body cannot use the insulin effectively. The end result
is the same as for type 1 diabetes--an unhealthy buildup
of glucose in the blood and an inability of the body to
make efficient use of its main source of fuel.
The symptoms
of type 2 diabetes develop gradually and are not as noticeable
as in type 1 diabetes. Symptoms include feeling tired
or ill, frequent urination (especially at night), unusual
thirst, weight loss, blurred vision, frequent infections,
and slow healing of sores.
Gestational
Diabetes
Gestational diabetes
develops or is discovered during pregnancy. This type usually
disappears when the pregnancy is over, but women who have
had gestational diabetes have a greater risk of developing
type 2 diabetes later in their lives.
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Diabetes
is widely recognized as one of the leading causes of death
and disability in the United States. According to death
certificate data, diabetes contributed to the deaths of
more than 193,140 persons in 1996.
Diabetes is
associated with long-term complications that affect almost
every major part of the body. It contributes to blindness,
heart disease, strokes, kidney failure, amputations, and
nerve damage. Uncontrolled diabetes can complicate pregnancy,
and birth defects are more common in babies born to women
with diabetes.
Diabetes cost
the United States $98 billion in 1997. Indirect costs,
including disability payments, time lost from work, and
premature death, totaled $54 billion; medical costs for
diabetes care, including hospitalizations, medical care,
and treatment supplies, totaled $44 billion.
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Diabetes
is not contagious. People cannot "catch" it from each other.
However, certain factors can increase one's risk of developing
diabetes. People who have family members with diabetes (especially
type 2 diabetes ), who are overweight, or who are African
American, Hispanic, or Native American are all at greater
risk of developing diabetes.
Type 1 diabetes
occurs equally among males and females, but is more common
in whites than in nonwhites. Data from the World Health
Organization's Multinational Project for Childhood Diabetes
indicate that type 1 diabetes is rare in most Asian, African,
and American Indian populations. On the other hand, some
northern European countries, including Finland and Sweden,
have high rates of type 1 diabetes. The reasons for these
differences are not known.
Type 2 diabetes
is more common in older people, especially older women
who are overweight, and occurs more often among African
Americans, Hispanics, and American Indians. Compared with
non-Hispanic whites, diabetes rates are about 60 percent
higher in African Americans and 110 to 120 percent higher
in Mexican Americans and Puerto Ricans. American Indians
have the highest rates of diabetes in the world. Among
Pima Indians living in the United States, for example,
half of all adults have type 2 diabetes. The prevalence
of diabetes is likely to increase because older people,
Hispanics, and other minority groups make up the fastest
growing segments of the U.S. population.
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Before
the discovery of insulin in 1921, all people with type 1
diabetes died within a few years after the appearance of
the disease. Although insulin is not considered a cure for
diabetes, its discovery was the first major breakthrough
in diabetes treatment.
Today, daily
injections of insulin are the basic therapy for type 1
diabetes. Insulin injections must be balanced with meals
and daily activities, and glucose levels must be closely
monitored through frequent blood sugar testing.
Diet, exercise,
and blood testing for glucose are also the basis for management
of type 2 diabetes. In addition, some people with type
2 diabetes take oral drugs or insulin to lower their blood
glucose levels.
People with
diabetes must take responsibility for their day-to-day
care. Much of the daily care involves trying to keep blood
sugar levels from going too low or too high. When blood
sugar levels drop too low--a condition known as hypoglycemia--a
person can become nervous, shaky, and confused. Judgment
can be impaired. Eventually, the person could pass out.
The treatment for low blood sugar is to eat or drink something
with sugar in it.
On the other
hand, a person can become very ill if blood sugar levels
rise too high, a condition known as hyperglycemia. Hypoglycemia
and hyperglycemia, which can occur in people with type
1 diabetes or type 2 diabetes, are both potentially life-threatening
emergencies.
People with
diabetes should be treated by a doctor who monitors their
diabetes control and checks for complications. Doctors
who specialize in diabetes are called endocrinologists
or diabetologists. In addition, people with diabetes often
see ophthalmologists for eye examinations, podiatrists
for routine foot care, dietitians for help in planning
meals, and diabetes educators for instruction in day-to-day
care.
The goal of
diabetes management is to keep blood glucose levels as
close to the normal (nondiabetic) range as safely possible.
A recent Government study, sponsored by the National Institute
of Diabetes and Digestive and Kidney Diseases (NIDDK),
proved that keeping blood sugar levels as close to normal
as safely possible reduces the risk of developing major
complications of diabetes.
The 10-year
study, called the Diabetes Control and Complications Trial
(DCCT), was completed in 1993 and included 1,441 people
with type 1 diabetes. The study compared the effect of
two treatment approaches--intensive management and standard
management--on the development and progression of eye,
kidney, and nerve complications of diabetes. Researchers
found that study participants who maintained lower levels
of blood glucose through intensive management had significantly
lower rates of these complications.
Researchers
believe that DCCT findings have important implications
for the treatment of type 2 diabetes, as well as type
1 diabetes.
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NIDDK
supports basic and clinical research in its own laboratories
and in research centers and hospitals throughout the United
States. It also gathers and analyzes statistics about diabetes.
Other institutes at the National Institutes of Health also
carry out research on diabetes-related eye diseases, heart
and vascular complications, pregnancy, and dental problems.
Other Government
agencies that sponsor diabetes programs are the Centers
for Disease Control and Prevention, the Indian Health
Service, the Health Resources and Services Administration,
the Bureau of Veterans Affairs, and the Department of
Defense.
Many organizations
outside of the Government support diabetes research and
education activities. These organizations include the
American Diabetes Association, the Juvenile Diabetes Foundation
International, and the American Association of Diabetes
Educators.
In recent years,
advances in diabetes research have led to better ways
to manage diabetes and treat its complications. Major
advances include:
- New forms
of purified insulin, such as human insulin produced
through genetic engineering.
- Better ways
for doctors to monitor blood glucose levels and for
people with diabetes to test their own blood glucose
levels at home.
- Development
of external and implantable insulin pumps that deliver
appropriate amounts of insulin, replacing daily injections.
- Laser treatment
for diabetic eye disease, reducing the risk of blindness.
- Successful
transplantation of kidneys in people whose own kidneys
fail because of diabetes.
- Better ways
of managing diabetic pregnancies, improving chances
of successful outcomes.
- New drugs
to treat type 2 diabetes and better ways to manage this
form of diabetes through weight control.
- Evidence
that intensive management of blood glucose reduces and
may prevent development of microvascular complications
of diabetes.
- Demonstration
that antihypertensive drugs called ACE-inhibitors prevent
or delay kidney failure in people with diabetes.
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In
the future, it may be possible to administer insulin through
nasal sprays or in the form of a pill or patch. Devices
that can "read" blood glucose levels without having to prick
a finger to get a blood sample are also being developed.
Researchers
continue to search for the cause or causes of diabetes
and ways to prevent and cure the disorder. Scientists
are looking for genes that may be involved in type 2 diabetes
and type 1 diabetes. Some genetic markers for type 1 diabetes
have been identified, and it is now possible to screen
relatives of people with type 1 diabetes to see if they
are at risk for diabetes.
The new Diabetes
Prevention Trial-- type 1 diabetes, sponsored by NIDDK,
identifies relatives at risk for developing type 1 diabetes
and treats them with low doses of insulin or with oral
insulin-like agents in the hope of preventing type 1 diabetes.
Similar research is carried out at other medical centers
throughout the world.
Transplantation
of the pancreas or insulin-producing beta cells offers
the best hope of cure for people with type 1 diabetes.
Some pancreas transplants have been successful. However,
people who have transplants must take powerful drugs to
prevent rejection of the transplanted organ. These drugs
are costly and may eventually cause serious health problems.
Scientists
are working to develop less harmful drugs and better methods
of transplanting pancreatic tissue to prevent rejection
by the body. Using techniques of bioengineering, researchers
are also trying to create artificial islet cells that
secrete insulin in response to increased sugar levels
in the blood.
For type 2 diabetes,
the focus is on ways to prevent diabetes. Preventive approaches
include identifying people at high risk for the disorder
and encouraging them to lose weight, exercise more, and
follow a healthy diet. The Diabetes Prevention Program,
another new NIDDK project, will focus on preventing the
disorder in high-risk populations.
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For
more information about type 1 diabetes, type 2 diabetes,
and gestational diabetes, as well as diabetes research,
statistics, and education, contact:
National Diabetes
Information Clearinghouse
1 Information Way
Bethesda, MD 20892-3560
(301) 654-3327.
The following
organizations also distribute materials and support programs
for people with diabetes and their families and friends:
American Association
of Diabetes Educators
100 West Monroe Street, 4th Floor
Chicago, IL 60603
(800) 338-3633 or (312) 424-2426
http://www.aadenet.org/
American Diabetes
Association
ADA National Service Center
1660 Duke Street
Alexandria, VA 22314
(800) 232-3472
(703) 549-1500
Juvenile Diabetes
Foundation International
120 Wall Street, 19th Floor
New York, NY 10005
(800) 223-1138
(212) 785-9500.
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What Is Diabetes?
- A disorder
of metabolism--the way the body digests food for energy
and growth.
What Are the
Different Types of Diabetes?
- Type 1 diabetes
- Type 2 diabetes
- Gestational
diabetes.
What Is the
Scope and Impact of Diabetes?
- Affects
16 million people
- A leading
cause of death and disability
- Costs $98
billion per year.
Who Gets Diabetes?
- People of
any age
- More common
in older people, African Americans, Hispanics, and American
Indians.
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National Diabetes
Information Clearinghouse
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NIH
Publication No. 96-3873
November 1998 |
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