Overview, Causes, & Risk Factors
Type 2 diabetes mellitus, more often known as type 2 diabetes, is the most common type of
diabetes. Unlike in type 1 diabetes,
people with type 2 diabetes may make healthy or even high levels of insulin. But, their body cells do not use
insulin effectively. This resistance to insulin is often caused by obesity.
Insulin is a hormone that helps control the level of glucose in the blood. Glucose is the main form of sugar in
the body. When the body cannot control the level of glucose, it has a hard time converting food into the
energy that the body needs to work. There are other forms of diabetes
as well.
What is going on in the body?
The pancreas, a long, thin organ located behind the stomach, makes insulin. In healthy people,
the pancreas makes extra insulin when a person eats. Insulin moves glucose from the bloodstream
into the body cells. The cells use glucose as their main energy source.
In a person with type 2 diabetes, however, even though the pancreas may make enough insulin,
the body cells are resistant to the effects of insulin. So they don't receive enough glucose and the blood
glucose level rises too high. This causes a condition called hyperglycemia, and it can cause damage to the
body, if left untreated.
What are the causes and risks of the disease?
Obesity is the
main cause of type 2 diabetes in both adults and children. A recent study showed a 33% increase in
the number of Americans with type 2 diabetes during the past 8 years. The increase was 70% in people
who were 30 to 39 years of age.
Type 2 diabetes accounts for about 90% to 95% of the cases of
diabetes in the US.
Type 2 diabetes used to be rare in children, but is now diagnosed in 20% of the children who
have diabetes. Of the children diagnosed with type 2 diabetes, 85% are
obese. At this time, most
children diagnosed with type 2 diabetes are 10 years of age or older. Researchers believe there will
be an increase in type 2 diabetes in younger children who become obese.
Type 2 diabetes is more common in people with a family history of the disease. It's also
more common among African Americans, Hispanic Americans, Pacific Islanders, Asian Americans, and Native
Americans.
Other risk factors for the development of type 2 diabetes include:
age of 45 or older
an HDL, the so-called
good cholesterol, level equal to or less than 35 mg/dL (milligrams per deciliter)
high blood pressure,
defined as a reading of 140/90 mmHg or higher
a history of gestational diabetes
or of having babies that weighed more than 9 pounds at birth
lack of physical activity
a triglyceride level
equal to or more than 250 mg/dL
A recent study of 16,000 American women between the ages of 40 and 65 years showed
that diabetes was listed as one of the top six diagnoses. A long-term study is under way to see if
menopause and
changes in hormone levels are factors in developing type 2 diabetes.
Almost all people who develop type 2 diabetes have a condition called
prediabetes first. This
condition used to be known as impaired glucose tolerance or impaired fasting
glucose, and the ADA estimates that almost 16 million people over the age of 40
have it. This condition occurs when blood glucose levels are higher than healthy
levels but too low to be diagnosed as diabetes. Without lifestyle changes, most
people who have prediabetes will progress to type 2 diabetes within 10 years.
Symptoms & Signs
What are the signs and symptoms of the disease?
Symptoms of type 2 diabetes usually develop slowly over time. They are not as noticeable
as in type 1 diabetes. Many people who have type 2 diabetes never have any symptoms at all. If they do
develop symptoms, they are usually linked to high levels of glucose in the blood and can include:
excessive hunger
excessive thirst
fatigue
and weakness
frequent urination
and an increase in the amount of urine passed
infections of the skin, vagina, bladder, or other areas
nausea
vomiting
visual problems,
such as blurred vision
weight loss in spite of
increased appetite and thirst
Diabetic ketoacidosis
sometimes occurs in people with type 2 diabetes. When the cells in the body don't get enough glucose,
the body starts to burn fat for energy. This produces waste products known as ketones. High levels of
ketones can result in too much acid in the body, called ketoacidosis. This condition requires medical
attention right away to prevent coma and death. Symptoms it can cause include:
dehydration
dry lips
sunken eyes
labored breathing
vomiting
abdominal distress,
fruity-smelling breath
Diagnosis & Tests
How is the disease diagnosed?
A doctor may suspect diabetes after taking a person's health history and
doing a physical exam. Based on those results, the doctor may want to check for a
high glucose level in the blood. There are several types of blood tests doctors can
use to diagnose diabetes, including:
fasting plasma glucose test,
which is the most common method to diagnose most cases of diabetes. In this test,
a person is asked to fast overnight for at least 8 hours. In the morning, the level of
glucose in the blood is then checked. Healthy fasting plasma glucose levels are
less than 110 milligrams per deciliter or mg/dL. A fasting plasma glucose level of
more than 126 mg/dL usually suggests diabetes. Levels between 110 and 126 mg/dL
are seen in prediabetes.
oral glucose tolerance test,
which is the preferred way to diagnose gestational diabetes.
It can also be used to diagnose type 2 diabetes and prediabetes. In this test, a
person is asked to drink a sweet liquid. Blood samples are then drawn at timed
intervals. If a person does not have diabetes, the glucose levels will rise and then
fall quickly after drinking the sweet liquid. When a person has diabetes, glucose
levels will rise higher and fail to come down as fast as those in a person without
diabetes. If the blood glucose level is 140 to 199 mg/dL 2 hours after drinking the
liquid, a diagnosis of prediabetes can be made.
plasma glucose test,
which can be done without fasting and is used as a screening tool. A level of
200 mg/dL or higher suggests diabetes. If the level is above 200 mg/dL on two separate days,
a fasting glucose test or oral glucose tolerance test
can be done to confirm the diagnosis of diabetes.
Prevention & Expectations
What can be done to prevent the disease?
The best way to prevent type 2 diabetes is through modest lifestyle changes. These
changes can be helpful to almost any person's health, but if a person has been diagnosed with
prediabetes, lifestyle changes are essential. The key is to:
maintain a healthy body weight
eat a healthy diet for diabetes
exercise 30 minutes a day at least 5 days a week
The Disease Prevention Program, a federally funded study, demonstrated the effect of
lifestyle changes on a person's risk factors for type 2 diabetes. Participants in the study exercised
moderately for 150 minutes a week. Most of them chose to walk briskly for 30 minutes, 5 days a
week. They also ate a reduced-fat diet with large amounts of vegetables. The weight loss goal was 7%,
or 14 pounds for a person weighing 200 pounds. With these changes, the individuals lowered their
risk of developing type 2 diabetes by 58%.
What are the long-term effects of the disease?
Over time, high blood sugar levels damage blood vessels, nerves, and
other internal structures. Long-term effects of diabetes may include:
Retinopathy, a disease in the retina of the eye that can cause blindness.
Diabetes is the number one cause of blindness in adults who are younger than
age 40.
Diabetic nephropathy,
which is a disease of the kidneys. This disease can progress to a form of kidney
failure known as chronic renal failure.
Diabetes is the leading cause of chronic renal failure.
Atherosclerosis,
also known as hardening of the arteries. Atherosclerosis can lead to
heart attacks
and strokes.
It can also cause poor circulation in the legs and feet.
Diabetic neuropathy,
which means damage to nerves in the arms and legs. This damage can cause numbness and pain in
the hands and feet. When combined with poor circulation, neuropathy can result in
diabetic foot ulcers
and leg infections that may require amputation.
Autonomic neuropathy, which is a disorder that affects certain nerves. It
may cause problems with digestion,
diarrhea,
erectile dysfunction, a rapid heartbeat,
and low blood pressure.
Coma
or death may occur as a result of diabetic ketoacidosis.
In addition, smoking
greatly increases the risk of getting many of these long-term effects. People with
diabetes who smoke are a much higher risk for heart attacks,
strokes,
infections, and problems with circulation.
What are the risks to others?
Type 2 diabetes is not catching and poses no risk to others. It does tend to
run in families.
Treatment & Monitoring
What are the treatments for the disease?
The most effective treatment for type 2 diabetes is a change in lifestyle, including the following:
Weight loss. Loss
of as little as 10 to 15 pounds can help keep blood glucose levels under control.
Healthy eating. A healthy
diet can help with weight loss. And that can prevent the need for medicine.
Regular exercise.
Walking only 30 minutes a day can lead to better glucose control.
A person with type 2 diabetes may also be treated with
oral medicines and/or insulin shots. Diabetes pills can work in four ways.
They can stimulate the pancreas to make more insulin.
They can help the cells in the body use insulin and glucose better.
They can keep the starches that are eaten from being broken down into glucose in
your intestines.
They can reduce the amount of glucose that is released from the liver.
Careful monitoring and management help keep diabetes under
control and reduce the risk of long-term effects. A person with diabetes should:
monitor his or her blood glucose levels at home
take medicines as prescribed by the doctor
know how to recognize and treat hypoglycemia,
which is low blood glucose
get regular eye checkups that include an examination of the retina after the
pupil of the eye has been dilated with eye drops
do thorough foot care
on a daily basis
follow a plan to monitor and treat changing blood glucose levels when sick or
under stress
follow a healthy diet
have regular checkups with the doctor
get a pneumonia shot
get a flu shot each fall
Treating the complications of diabetes may involve many different
specialists. For example, a person with diabetes may need to see eye, heart, foot,
hormone, and circulation specialists. Dieticians also help people with diabetes by
designing a healthy eating plan. Dieticians can also suggest healthy calorie intake levels
and types of foods to eat.
What are the side effects of the treatments?
The oral medicines used for type 2 diabetes may cause weight gain, diarrhea,
gas, allergic reactions,
or liver damage. Some may also cause blood glucose levels to go too low. This condition is known as
hypoglycemia. It can
cause:
nervousness
shakiness
confusion
hunger
sweating
nausea
If this condition goes untreated, a person can pass out. The usual treatment for low blood
glucose is to drink a sweet beverage or eat a sweet food. If low blood glucose goes untreated, a person
may pass out or have seizures. Emergency medical care is crucial in this situation.
What happens after treatment for the disease?
Although type 2 diabetes cannot be cured, it can be controlled with careful management.
The person will need lifelong monitoring and treatment to help prevent serious complications.
How is the disease monitored?
A person with diabetes should keep all of appointments
with his or her primary doctor, as well as other scheduled specialists.
Physical exams, blood tests, urine tests, foot and skin care, routine eye exams,
and routine dental care are all part of basic care for a person with diabetes. The
main goal of treatment is to keep blood glucose levels as close to a healthy range
as is safely possible. In general, ideal ranges of blood glucose levels are 80 to 120
milligrams per deciliter (mg/dL) before meals and 100 to 140 mg/dL at bedtime. Any
new or worsening symptoms should be reported to the doctor.