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.
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
Complications of diabetes
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.
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
- Diabetic retinopathy causes from 12,000 to 24,000 new cases of blindness each year.
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
More than half of lower limb amputations
in the United States occur among people with diabetes.
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
- 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
* Diabetic ketoacidosis and hyperosmolar nonketotic coma are medical conditions
that can result from very high glucose level and biochemical imbalance in uncontrolled
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
- 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
** 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.
Impaired fasting glucose
- 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 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.
Pills to treat type 2 diabetes
- 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)
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
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
- 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
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.