Diabetes
 

Overview
 

National Diabetes Information Clearinghouse 

U.S. Department 

of Health and 

Human Services 

NATIONAL 

INSTITUTES 

OF HEALTH 

Almost everyone knows someone who 

has diabetes. An estimated 23.6 million 

people in the United States—7.8 percent of 

the population—have diabetes, a serious, 

lifelong condition. Of those, 17.9 million 

have been diagnosed, and 5.7 million have 

not yet been diagnosed. In 2007, about 

1.6 million people ages 20 or older were 

diagnosed with diabetes. For additional 

statistics, see the National Diabetes Statistics, 

2007 fact sheet online at www.diabetes.niddk. 

nih.gov/dm/pubs/statistics or call the National 

Diabetes Information Clearinghouse (NDIC) 

at 1–800–860–8747 to request a copy. 

What is diabetes? 

Diabetes is a disorder of metabolism— 

the way the body uses digested food for 

growth and energy. Most of the food people 

eat is broken down into glucose, the form 

of sugar in the blood. Glucose is the main 

source of fuel for the body. 

After digestion, glucose passes into the 

bloodstream, where it is used by cells for 

growth and energy. For glucose to get into 

cells, insulin must be present. Insulin is a 

hormone produced by the pancreas, a large 

gland behind the stomach. 

When people eat, the pancreas automatically 

produces the right amount of insulin to move 

glucose from blood into the cells. In people 

with diabetes, however, the pancreas either 

produces little or no insulin, or the cells do 

not respond appropriately to the insulin that 

Estimated prevalence of diagnosed 

and undiagnosed diabetes in people 

ages 20 years or older, by age group, 

United States, 2007 

0

5

10

15

20

25

20–39 40–59 60+

Age Group 

2.6

10.8

23.8

Percent 

Source: 2003–2006 National Health and Nutrition 

Examination Survey estimates of total prevalence— 

both diagnosed and undiagnosed—were projected to 

year 2007. 

is produced. Glucose builds up in the blood, 

overflows into the urine, and passes out of 

the body in the urine. Thus, the body loses 

its main source of fuel even though the blood 

contains large amounts of glucose. 
What are the types of 

diabetes? 

The three main types of diabetes are 

• type 1 diabetes 

• type 2 diabetes 

• gestational diabetes 

Type 1 Diabetes 

Type 1 diabetes is an autoimmune disease. 

An autoimmune disease results when the 

body’s system for fi ghting infection—the 

immune system—turns against a part of 

the body. In diabetes, the immune system 

attacks and destroys the insulin-producing 

beta cells in the pancreas. The pancreas 

then produces little or no insulin. A person 

who has type 1 diabetes must take insulin 

daily 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 

autoimmune, genetic, and environmental factors, possibly viruses, are involved. 

Type 1 diabetes accounts for about 5 to 

10 percent of diagnosed diabetes in the 

United States. It develops most often in 

children and young adults but 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 may include increased thirst and 

urination, constant hunger, weight loss, 

blurred vision, and extreme fatigue. If not 

diagnosed and treated with insulin, a person 

with type 1 diabetes can lapse into a lifethreatening diabetic coma, also known as 

diabetic ketoacidosis. 

Type 2 Diabetes 

The most common form of diabetes is type 2 

diabetes. About 90 to 95 percent of people 

with diabetes have type 2. This form of diabetes is most often associated with older age, 

obesity, family history of diabetes, previous 

history of gestational diabetes, physical 

inactivity, and certain ethnicities. About 

80 percent of people with type 2 diabetes are 

overweight. 

Type 2 diabetes is increasingly being 

diagnosed in children and adolescents, especially among African American, Mexican 

American, and Pacific Islander youth. 

When type 2 diabetes is diagnosed, the pancreas is usually producing enough insulin, but 

for unknown reasons the body cannot use the 

insulin effectively, a condition called insulin 

resistance. After several years, insulin production decreases. The result is the same as 

for type 1 diabetes—glucose builds up in the 

blood and the body cannot make effi cient use 

of its main source of fuel. 

The symptoms of type 2 diabetes develop 

gradually. Their onset is not as sudden as 

in type 1 diabetes. Symptoms may include 

fatigue, frequent urination, increased thirst 

and hunger, weight loss, blurred vision, and 

slow healing of wounds or sores. Some 

people have no symptoms. 

Gestational Diabetes 

Some women develop gestational diabetes 

late in pregnancy. Although this form of 

diabetes usually disappears after the birth of 

the baby, women who have had gestational 

diabetes have a 40 to 60 percent chance 

of developing type 2 diabetes within 5 to 

10 years. Maintaining a reasonable body 

weight and being physically active may help 

prevent development of type 2 diabetes. 

2 Diabetes Overview 
About 3 to 8 percent of pregnant women 

in the United States develop gestational 

diabetes. As with type 2 diabetes, gestational diabetes occurs more often in some 

ethnic groups and among women with a 

family history of diabetes. Gestational 

diabetes is caused by the hormones of 

pregnancy or a shortage of insulin. Women 

with gestational diabetes may not experience any symptoms. 

Diabetes in Youth 

The SEARCH for Diabetes in Youth multicenter study, funded by the Centers for Disease Control and Prevention (CDC) and 

the National Institutes of Health (NIH), 

has determined that 

• 	 based on data from 2002 to 2003, a 

total of 15,000 youth in the United 

States were newly diagnosed with 

type 1 diabetes each year. In addition, about 3,700 youth were newly 

diagnosed with type 2 diabetes each 

year. 

• 	 non-Hispanic white youth had the 

highest rate of new cases of type 1 

diabetes. 

• 	type 2 diabetes was rarely diagnosed 

among youth younger than 10 years 

of age. 

Additional information about specifi c rates 

of new cases of type 1 and type 2 diabetes 

among youth younger than age 20 can be 

found in the fact sheet National Diabetes 

Statistics, 2011, available online at www. 

diabetes.niddk.nih.gov/dm/pubs/statistics. 

Other Types of Diabetes 

A number of other types of diabetes exist. A 

person may exhibit characteristics of more 

than one type. For example, in latent autoimmune diabetes in adults (LADA), also 

called type 1.5 diabetes or double diabetes, 

people show signs of both type 1 and type 2 

diabetes. 

Other types of diabetes include those caused 

by 

• 	 genetic defects of the beta cell—the 

part of the pancreas that makes 

insulin—such as maturity-onset 

diabetes of the young (MODY) or 

neonatal diabetes mellitus (NDM) 

• 	 genetic defects in insulin action, resulting in the body’s inability to control 

blood glucose levels, as seen in leprechaunism and the Rabson-Mendenhall 

syndrome 

• 	 diseases of the pancreas or conditions 

that damage the pancreas, such as pancreatitis and cystic fibrosis 

• 	 excess amounts of certain hormones 

resulting from some medical 

conditions—such as cortisol in 

Cushing’s syndrome—that work 

against the action of insulin 

• 	 medications that reduce insulin action, 

such as glucocorticoids, or chemicals 

that destroy beta cells 

• 	 infections, such as congenital rubella 

and cytomegalovirus 

3 	 Diabetes Overview 
• 	rare immune-mediated disorders, such 

as stiff-man syndrome, an autoimmune 

disease of the central nervous system 

• 	 genetic syndromes associated with 

diabetes, such as Down syndrome and 

Prader-Willi syndrome 

Latent Autoimmune Diabetes 

in Adults (LADA) 

People who have LADA show signs of both 

type 1 and type 2 diabetes. Diagnosis usually occurs after age 30. Researchers estimate that as many as 10 percent of people 

diagnosed with type 2 diabetes have LADA. 

Some experts believe that LADA is a slowly 

developing kind of type 1 diabetes because 

patients have antibodies against the insulinproducing beta cells of the pancreas. 

Most people with LADA still produce their 

own insulin when first diagnosed, like those 

with type 2 diabetes. In the early stages 

of the disease, people with LADA do not 

require insulin injections. Instead, they 

control their blood glucose levels with meal 

planning, physical activity, and oral diabetes 

medications. However, several years after 

diagnosis, people with LADA must take 

insulin to control blood glucose levels. As 

LADA progresses, the beta cells of the pancreas may no longer make insulin because 

the body’s immune system has attacked and 

destroyed them, as in type 1 diabetes. 

Diabetes Caused by Genetic 

Defects of the Beta Cell 

Genetic defects of the beta cell cause several 

forms of diabetes. For example, monogenic 

forms of diabetes result from mutations, or 

changes, in a single gene. In most cases of 

monogenic diabetes, the gene mutation is 

inherited. In the remaining cases, the gene 

mutation develops spontaneously. Most 

mutations in monogenic diabetes reduce the 

body’s ability to produce insulin. Genetic 

testing can diagnose most forms of monogenic diabetes. 

NDM and MODY are the two main forms 

of monogenic diabetes. NDM is a form of 

diabetes that occurs in the first 6 months 

of life. Infants with NDM do not produce 

enough insulin, leading to an increase in 

blood glucose. NDM can be mistaken for 

the much more common type 1 diabetes, but 

type 1 diabetes usually occurs after the fi rst 

6 months of life. More information about 

the two types of NDM, permanent neonatal 

diabetes and transient neonatal diabetes mellitus, is provided in the fact sheet Monogenic 

Forms of Diabetes, available online from the 

NDIC at www.diabetes.niddk.nih.gov/dm/ 

pubs/mody. For printed copies of the fact 

sheet, call the NDIC at 1–800–860–8747. 

MODY usually first occurs during adolescence or early adulthood. However, MODY 

sometimes remains undiagnosed until later 

in life. A number of different gene mutations have been shown to cause MODY, 

all of which limit the pancreas’ ability to 

produce insulin. This process leads to the 

high blood glucose levels characteristic of 

diabetes. More information about specifi c 

types of MODY is provided in the fact sheet 

Monogenic Forms of Diabetes. 

4 	 Diabetes Overview 
Diabetes Caused by Genetic 

Defects in Insulin Action 

A number of types of diabetes result from 

genetic defects in insulin action. Changes 

to the insulin receptor may cause mild 

hyperglycemia—high blood glucose—or 

severe diabetes. Symptoms may include 

acanthosis nigricans, a skin condition 

characterized by darkened skin patches, 

and, in women, enlarged and cystic ovaries 

plus virilization and the development of 

masculine characteristics such as excess 

facial hair. Two syndromes in children, 

leprechaunism and the Rabson-Mendenhall 

syndrome, cause extreme insulin resistance. 

Diabetes Caused by Diseases 

of the Pancreas 

Injuries to the pancreas from trauma or 

disease can cause diabetes. This category 

includes pancreatitis, infection, and cancer 

of the pancreas. Cystic fibrosis and hemochromatosis can also damage the pancreas 

enough to cause diabetes. 

Diabetes Caused by 

Endocrinopathies 

Excess amounts of certain hormones that 

work against the action of insulin can cause 

diabetes. These hormones and their related 

conditions include growth hormone in 

acromegaly, cortisol in Cushing’s syndrome, 

glucagon in glucagonoma, and epinephrine 

in pheochromocytoma. 

Diabetes Caused by 

Medications or Chemicals 

A number of medications and chemicals 

can interfere with insulin secretion, leading 

to diabetes in people with insulin resistance. These medications and chemicals 

include pentamidine, nicotinic acid, glucocorticoids, thyroid hormone, phenytoin 

(Dilantin), and Vacor, a rat poison. 

Diabetes Caused by Infections 

Several infections are associated with the 

occurrence of diabetes, including congenital rubella, coxsackievirus B, cytomegalovirus, adenovirus, and mumps. 

Rare Immune-mediated 

Types of Diabetes 

Some immune-mediated disorders are 

associated with diabetes. About one-third 

of people with stiff-man syndrome develop 

diabetes. In other autoimmune diseases, 

such as systemic lupus erythematosus, 

patients may have anti-insulin receptor 

antibodies that cause diabetes by interfering with the binding of insulin to body 

tissues. 

Other Genetic Syndromes 

Sometimes Associated with 

Diabetes 

Many genetic syndromes are associated 

with diabetes. These conditions include 

Down syndrome, Klinefelter’s syndrome, 

Huntington’s chorea, porphyria, PraderWilli syndrome, and diabetes insipidus. 

5 Diabetes Overview 
6    Diabetes Overview

How is diabetes diagnosed?

The fasting blood glucose test is the preferred test for diagnosing diabetes in children and nonpregnant adults.  The test is 

most reliable when done in the morning.  

However, a diagnosis of  diabetes can be 

made based on any of the following test 

results, confirmed by retesting on a different 

day:

• A blood glucose level of 126 milligrams    

per deciliter (mg/dL) or higher after an 

8-hour fast.  This test is called the fasting blood glucose test.

•  A blood glucose level of 200 mg/dL or 

higher 2 hours after drinking a beverage containing 75 grams of glucose dissolved in water.  This test is called the 

oral glucose tolerance test (OGTT).

• A random —taken at any time of 

day—blood glucose level of 200 mg/dL 

or higher, along with the presence of 

diabetes symptoms.

Gestational diabetes is diagnosed based  

on blood glucose levels measured during the 

OGTT.  Glucose levels are normally lower 

during pregnancy, so the cutoff levels for 

diagnosis of diabetes in pregnancy are  lower.  

Blood glucose levels are measured before a 

woman drinks a beverage containing glucose.  

Then levels are checked 1, 2, and 3 hours 

afterward.  If a woman has two blood glucose 

levels meeting or exceeding any of the 

following   numbers, she has gestational 

 diabetes:  a fasting blood  glucose level 

of 95 mg/dL, a 1-hour level of 180 mg/dL, a 

2-hour level of 155 mg/dL, or a 3-hour level 

of 140 mg/dL.

What is prediabetes?

People with prediabetes have blood glucose 

levels that are higher than normal but not 

high enough for a diagnosis of diabetes.  

This condition raises the risk of developing 

type 2 diabetes, heart disease, and stroke.

Prediabetes is also called impaired fasting glucose (IFG) or impaired glucose 

tolerance (IGT), depending on the test used 

to diagnose it.  Some people have both IFG 

and IGT.

• IFG is a condition in which the  

blood glucose level is high—100 to  

125 mg/dL—after an overnight fast, 

but is not high enough to be classified 

as diabetes.  The former definition of 

IFG was 110 mg/dL to 125 mg/dL.

• IGT is a condition in which the  

blood glucose level is high—140 to  

199 mg/dL—after a 2-hour OGTT, 

but is not high enough to be  classified 

as diabetes.

Prediabetes is becoming more common in 

the United States.  The U.S. Department of 

Health and Human Services estimates that 

at least 57 million U.S. adults ages 20 or 

older had prediabetes in 2007.  Those with 

prediabetes are likely to develop type 2 diabetes within 10 years, unless they take steps 

to prevent or delay diabetes.

The good news is that people with prediabetes can do a lot to prevent or delay diabetes. 

Studies have clearly shown that people can 

lower their risk of developing diabetes by 

losing 5 to 7 percent of their body weight 

through diet and increased physical activity.  
7    Diabetes Overview

A major study of more than 3,000 people 

with IGT found that diet and exercise resulting in a 5 to 7 percent weight loss—about 

10 to 14 pounds in a person who weighs 200 

pounds— lowered the incidence of type 2 

diabetes by nearly 60 percent.  Study participants lost weight by cutting fat and calories 

in their diet and by exercising—most chose 

walking—at least 30 minutes a day, 5 days 

a week.

What are the scope and 

impact of diabetes?

Diabetes is widely recognized as one of 

the leading causes of death and disability 

in the United States.  In 2006, it was the 

seventh leading cause of death.  However, 

diabetes is likely to be underreported as the 

under lying cause of death on death certificates.  In 2004, among people ages 65 years 

or older, heart disease was noted on 68 percent of diabetes-related death certificates; 

stroke was noted on 16 percent of diabetesrelated death certificates for the same age 

group.

Diabetes is associated with long-term 

complications that affect almost every part of 

the body.  The disease often leads to blindness, heart and blood vessel disease, stroke, 

kidney failure, amputations, and nerve damage.  Uncontrolled diabetes can complicate 

pregnancy, and birth defects are more common in babies born to women with diabetes.

In 2007, diabetes cost the United States 

$174 billion.  Indirect costs, including disability payments, time lost from work, and 

reduced productivity, totaled $58 billion. 

Direct medical costs for diabetes care, 

including hospitalizations, medical care, and 

treatment supplies, totaled $116 billion.

Who gets diabetes?

Diabetes is not contagious.  People cannot 

“catch” it from each other.  However, certain 

factors can increase the 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 African, American 

Indian, and Asian populations.  However, 

some northern European countries, including Finland and Sweden, have high rates of 

type 1 diabetes.  The reasons for these differences are unknown.  Type 1 diabetes develops most often in children but can occur at 

any age.

Type 2 diabetes is more common in older 

people, especially in people who are overweight, and occurs more often in African 

Americans, American Indians, some Asian 

Americans, Native Hawaiians and other 

Pacific Islander Americans, and Hispanics/

Latinos.  National survey data in 2007 

indicate a range in the prevalence of diagnosed and undiagnosed diabetes in various 

populations ages 20 years or older:

• Age 20 years or older:  23.5 million, or 

10.7 percent, of all people in this age 

group have diabetes.

•  Age 60 years or older:  12.2 million, or 

23.1 percent, of all people in this age 

group have diabetes.

• Men:  12.0 million, or 11.2 percent, 

of all men ages 20 years or older have 

diabetes.

• Women:  11.5 million, or 10.2 percent, 

of all women ages 20 years or older 

have diabetes.
• 	Non-Hispanic whites: 14.9 million, or 

9.8 percent, of all non-Hispanic whites 

ages 20 years or older have diabetes. 

• 	Non-Hispanic blacks: 3.7 million, 

or 14.7 percent, of all non-Hispanic 

blacks ages 20 years or older have 

diabetes. 

Diabetes prevalence in the United States 

is likely to increase for several reasons. First, 

a large segment of the population is aging. 

Also, Hispanics/Latinos and other minority 

groups at increased risk make up the fastestgrowing segment of the U.S. population. 

Finally, Americans are increasingly overweight and sedentary. According to recent 

estimates from the CDC, diabetes will 

affect one in three people born in 2000 in 

the United States. The CDC also projects 

that the prevalence of diagnosed diabetes in 

the United States will increase 165 percent 

by 2050. 

How is diabetes managed? 

Before the discovery of insulin in 1921, 

everyone with type 1 diabetes died within a 

few years after diagnosis. Although insulin 

is not considered a cure, its discovery was 

the first major breakthrough in diabetes 

treatment. 

Today, healthy eating, physical activity, and 

taking insulin are the basic therapies for type 

1 diabetes. The amount of insulin must be 

balanced with food intake and daily activities. Doctors may also prescribe another 

type of injectable medicine. Blood glucose 

levels must be closely monitored through 

frequent blood glucose checking. People 

with diabetes also monitor blood glucose 

levels several times a year with a laboratory 

test called the A1C. Results of the A1C test 

reflect average blood glucose over a 2- to 

3-month period. 

Healthy eating, physical activity, and blood 

glucose testing are the basic management 

tools for type 2 diabetes. In addition, many 

people with type 2 diabetes require one or 

more diabetes medicines—pills, insulin, and 

other injectable medicine—to control their 

blood glucose levels. 

Adults with diabetes are at high risk for 

cardiovascular disease (CVD). In fact, at 

least 65 percent of those with diabetes die 

from heart disease or stroke. Managing 

diabetes is more than keeping blood glucose 

levels under control—it is also important 

to manage blood pressure and cholesterol 

levels through healthy eating, physical activity, and the use of medications, if needed. 

By doing so, those with diabetes can lower 

their risk. Aspirin therapy, if recommended 

by a person’s health care team, and smoking 

cessation can also help lower risk. 

People with diabetes must take 

responsibility for their day-to-day care. 

Much of the daily care involves keeping 

blood glucose levels from going too low 

or too high. When blood glucose levels 

drop too low—a condition known as 

hypoglycemia—a person can become 

nervous, shaky, and confused. Judgment 

can be impaired, and if blood glucose falls 

too low, fainting can occur. 

A person can also become ill if blood 

glucose levels rise too high. 

People with diabetes should see a health 

care provider who will help them learn 

to manage their diabetes and who will 

monitor their diabetes control. Most 

8 	 Diabetes Overview 
people with diabetes get care from primary 

care physicians—internists, family practice 

doctors, or pediatricians. Often, having a 

team of providers can improve diabetes care. 

A team can include 

• 	 a primary care provider such as an 

internist, a family practice doctor, or 

a pediatrician 

• 	 an endocrinologist—a specialist in 


 diabetes care
 

• 	 a dietitian, a nurse, and other 

health care providers who are certified diabetes educators—experts 

in providing information about 

managing diabetes 

• 	 a podiatrist—for foot care 

• 	 an ophthalmologist or an 


optometrist—for eye care
 

The team can also include other health care 

providers, such as cardiologists and other 

specialists. The team for a pregnant woman 

with type 1, type 2, or gestational diabetes 

should include an obstetrician who specializes in caring for women with diabetes. The 

team can also include a pediatrician or a 

neonatologist with experience taking care of 

babies born to women with diabetes. 

The goal of diabetes management is to keep 

levels of blood glucose, blood pressure, and 

cholesterol as close to the normal range as 

safely possible. A major study, the Diabetes 

Control and Compli cations Trial (DCCT), 

sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases 

(NIDDK), showed that keeping blood glucose levels close to normal reduces the risk 

of developing major complications of type 1 

diabetes. 

This 10-year study, completed in 1993, 

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, nerve, and cardiovascular 

complications of diabetes. Intensive 

treatment aimed to keep A1C levels as 

close to normal—6 percent—as possible. 

Researchers found that study participants 

who maintained lower levels of blood 

glucose through intensive management 

had significantly lower rates of these 

complications. More recently, a follow-up 

study of DCCT participants showed that 

the ability of intensive control to lower the 

complications of diabetes has persisted more 

than 10 years after the trial ended. 

The United Kingdom Prospective Diabetes 

Study, a European study completed in 1998, 

showed that intensive control of blood glucose and blood pressure reduced the risk of 

blindness, kidney disease, stroke, and heart 

attack in people with type 2 diabetes. 

Hope through Research 

The NIDDK conducts research in its own 

laboratories and supports a great deal of 

basic and clinical research in medical centers and hospitals throughout the United 

States. It also gathers and analyzes statistics 

about diabetes. Other Institutes at the NIH 

conduct and support research on diabetesrelated eye diseases, heart and vascular 

complications, autoimmunity, pregnancy, 

and dental problems. 

Other Government agencies that sponsor 

diabetes programs are the CDC, the Indian 

Health Service, the Health Resources and 

Services Administration, the Department 

of Veterans Affairs, and the Department 

of Defense. 

9 	 Diabetes Overview 
Many organizations outside the Government support diabetes research and education activities. These organizations include 

the American Diabetes Association (ADA), 

the Juvenile Diabetes Research Foundation 

International (JDRF), and the American 

Association of Diabetes Educators. 

In recent years, advances in diabetes 

research have led to better ways of managing diabetes and treating its complications. 

Major advances include 

• 	 development of quick-acting and 


long-acting insulins
 

• 	 better ways to monitor blood glucose 

and for people with diabetes to check 

their blood glucose levels 

• 	 development of external insulin pumps 

that deliver insulin, replacing daily 

injections 

• 	 laser treatment for diabetic eye disease, reducing the risk of blindness 

• 	successful kidney and pancreas transplantation in people whose kidneys 

fail because of diabetes 

• 	 better ways of managing diabetes in 

pregnant women, improving their 

chances of a successful outcome 

• 	 new drugs to treat type 1 and type 2 

diabetes and better ways to manage these forms of diabetes through 

weight control 

• 	 evidence that intensive management 

of blood glucose reduces and may 

prevent development of diabetes 

complications 

• 	demonstration that two types of 

antihypertensive drugs, angiotensinconverting enzyme (ACE) inhibitors 

and angiotensin receptor blockers 

(ARBs), are more effective than other 

antihypertensive drugs in reducing a 

decline in kidney function in people 

with diabetes 

• 	 advances in transplantation of islets— 

clusters of cells that produce insulin 

and other hormones—for type 1 

diabetes 

• 	 evidence that people at high risk for 

type 2 diabetes can lower their chances 

of developing the disease through diet, 

weight loss, and physical activity 

What will the future bring? 

Researchers continue to look for the cause 

or causes of diabetes and ways to manage, 

prevent, or cure the disorder. Scientists are 

searching for genes that may be involved 

in type 1 or type 2 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 

determine whether they are at risk. 

Type 1 Diabetes 

A number of federally funded research studies and clinical trials are under way. Studies 

focus on the prevention and causes of type 1 

diabetes as well as experimental treatments 

such as islet transplantation. 

Diabetes Prevention Trial–Type 1 

(DPT–1) 

The NIDDK and other groups sponsored 

DPT–1, which showed that people at risk for 

developing type 1 diabetes can be identifi ed. 

The DPT–1 researchers discovered ways to 

10 Diabetes Overview 
identify two populations at risk of developing type 1 diabetes within 5 years—those at 

high risk, with at least a 50 percent chance, 

and those at intermediate risk, with a 25 to 

50 percent risk. Then researchers explored 

possible ways of preventing type 1 diabetes 

in both groups. Although the study found 

that neither low-dose insulin injections nor 

insulin capsules taken orally prevented or 

delayed type 1 diabetes in the study population, research that follows up on DPT–1 

findings is under way. For more information about DPT–1, see www.niddk.nih.gov/ 

patient/dpt_1/dpt_1.htm. 

The Environmental Determinants 

of Diabetes in the Young (TEDDY) 

Consortium 

The main mission of the TEDDY consortium, an international group of clinical centers, is to identify infectious agents, dietary 

factors, or other environmental factors— 

including psychosocial events—that trigger 

type 1 diabetes in those who are genetically 

susceptible. In addition, the consortium 

aims to 

• 	 create a central repository of data 

and biological samples for use by 

researchers 

• 	 develop novel approaches to finding 

the causes of type 1 diabetes 

• 	find ways to understand how the 


disease starts and progresses
 

• 	 discover new methods to prevent, 


delay, and reverse type 1 diabetes
 

TEDDY is funded by the NIDDK, the 

National Institute of Allergy and Infectious 

Diseases (NIAID), the National Institute 

of Child Health and Human Development 

(NICHD), the National Institute of Environmental Health Sciences, the CDC, the 

JDRF, and the ADA. For more information, see http://teddy.epi.usf.edu. 

Type 1 Diabetes Genetics 

Consortium (T1DGC) 

The T1DGC is a group of researchers from 

around the world who are studying the 

genetics of type 1 diabetes. They are studying families with siblings who have type 1 

diabetes to look for genes that may show a 

person’s risk of getting type 1 diabetes or 

might keep someone from getting type 1 

diabetes. For more information, see 

www.t1dgc.org. 

Type 1 Diabetes TrialNet 

Type 1 Diabetes TrialNet is a network of 

experts and facilities dedicated to developing new approaches to the understanding, prevention, and treatment of type 1 

diabetes. Clinical centers are located in 

the United States, Canada, Europe, and 

Australia. 

TrialNet studies are focusing on 

• 	 understanding the natural history 


of type 1 diabetes to determine its 


causes and progression
 

• 	 preventing type 1 diabetes in those 

at risk 

• 	 developing ways to preserve the function of the insulin-producing cells in 

the pancreas in people recently diagnosed with type 1 diabetes 

For more information, see 

www.DiabetesTrialNet.org or call 

1–800–HALT–DM1 (1–800–425–8361). 

TrialNet will identify people at risk who 

may be eligible for clinical trials. In addition, TrialNet will conduct trials to save beta 

cell function in those with new onset type 1 

diabetes. 

11 Diabetes Overview 
TrialNet is funded by the NIDDK, NICHD, 

and NIAID. The JDRF and ADA also 

support this effort. 

The Immune Tolerance Network 

TrialNet works closely with the Immune 

Tolerance Network, another international, 

collaborative consortium. Its goal is to fi nd 

safe and effective ways to induce longterm immune tolerance—prevention of an 

unwanted immune response by the body. 

For example, type 1 diabetes might be 

prevented if scientists could learn how to 

prevent the immune system from mistakenly attacking the insulin-producing cells in 

the pancreas. Effective immune tolerance 

could possibly 

• 	 prevent the body’s rejection of organ 

or tissue transplants 

• 	 prevent or treat autoimmune diseases 

• 	 prevent or treat allergies and asthma 

For more information, see 

www.immunetolerance.org or call 

415–514–2530. 

The Trial to Reduce IDDM in the 

Genetically at Risk (TRIGR) 

The TRIGR study will help determine 

whether delayed exposure to cow’s milk 

can prevent type 1 diabetes in infants at 

risk of developing the disease. Instead of 

receiving cow’s milk, infants in the TRIGR 

study will primarily breastfeed. Babies 

whose mothers cannot breastfeed will be 

given a special formula made with milk 

proteins that may be easier for babies to 

tolerate. The TRIGR study will help clarify 

whether infant feeding practices are related 

to the development of diabetes. For more 

information, see www.trigrnorthamerica.org 

or call 1–888–STOP–T1D (1–888–786–7813). 

Islet Transplantation 

Researchers are working on a way for people 

with type 1 diabetes to live without daily 

insulin injections. In an experimental procedure called islet transplantation, islets are 

taken from a donor pancreas and transferred 

into a person with type 1 diabetes. Once 

implanted, the beta cells in these islets begin 

to make and release insulin. 

Although scientists have made many 

advances in islet transplantation in recent 

years, transplanted islets tend to lose function over time, and few transplant recipients are able to stop using insulin for very 

long. But even partial islet function can 

help patients reduce their need for insulin, 

achieve better glucose stability, and reduce 

problems with hypoglycemia. 

Problems with islet transplantation include 

the severe shortage of islets available for 

transplants and the need for patients to take 

drugs with significant side effects to stop the 

immune system from rejecting 

the transplanted islets. Researchers are 

seeking solutions to these problems. 

For more information about islet transplantation, see the fact sheet Pancreatic Islet 

Transplantation at www.diabetes.niddk.nih. 

gov/dm/pubs/pancreaticislet. 

Type 2 Diabetes 

Diabetes Prevention Program 

In 1996, the NIDDK launched its Diabetes 

Prevention Program (DPP). The goal of this 

research effort was to learn how to prevent 

or delay type 2 diabetes in people with 

impaired glucose tolerance, a strong risk factor for type 2 diabetes. 

The findings of the DPP, released in 

August 2001, showed that people at high risk 

for type 2 diabetes could sharply lower their 

chances of developing the disorder through 

12 Diabetes Overview 
diet and exercise. In addition, treatment 

with the oral diabetes drug metformin also 

reduced diabetes risk, though less dramatically. Metformin lowers the amount of 

glucose released by the liver and also fi ghts 

insulin resistance, a condition in which the 

body doesn’t use insulin properly. 

Participants randomly assigned to intensive 

lifestyle intervention reduced their risk of 

getting type 2 diabetes by 58 percent. On 

average, this group maintained their physical 

activity at 30 minutes per day, usually with 

walking or other moderate intensity exercise, 

and lost 5 to 7 percent of their body weight. 

Participants randomized to treatment with 

metformin reduced their risk of getting type 2 

diabetes by 31 percent. 

Of the 3,234 participants enrolled in the 

DPP, 45 percent were from minority groups 

that suffer disproportionately from type 2 

diabetes: African Americans, Hispanics/ 

Latinos, Asian Americans and Pacifi c Islanders, and American Indians. The DPP also 

recruited other groups known to be at higher 

risk for type 2 diabetes, including individuals ages 60 or older, women with a history 

of gestational diabetes, and people with a 

first-degree relative with type 2 diabetes. 

Participants are still being followed to check 

for long-term effects of the interventions, 

including the effects on CVD. Recent analyses of data from the DPP have added to the 

evidence that lifestyle changes are especially 

effective in helping to reduce the risk of 

developing conditions associated with type 2 

diabetes, including high blood pressure and 

the metabolic syndrome. Researchers also 

confirmed that study participants carrying 

two copies of a gene variant that signifi cantly 

increased their risk of developing diabetes 

benefited from lifestyle changes as much as 

or more than those without the gene variant. 

Type 2 Diabetes in Children 

and Teens 

Two studies focusing on type 2 diabetes 

in children and teens are under way. The 

Treatment Options for type 2 Diabetes in 

Adolescents and Youth (TODAY) study, 

a 13-site study sponsored by the NIDDK, 

will compare treatments for type 2 diabetes in children and teens. Participants will 

undergo one of three treatments: 

• 	taking one diabetes medication—
 

metformin
 

• 	taking two diabetes medications—
 

metformin and rosiglitazone, 


another medication that fights 


insulin resistance
 

• 	taking metformin and participating 

in an intensive lifestyle change program designed to promote weight 

loss by cutting calories and increasing 

physical activity 

The main goal of the study is to determine 

how well each type of treatment controls 

blood glucose levels. The study also will 

evaluate how long each type of treatment 

is effective. 

Current NIDDK-sponsored research 

includes the HEALTHY study, which is 

part of a broad research initiative called 

STOPP T2D (Studies to Treat or Prevent 

Pediatric Type 2 Diabetes). The study 

explores whether improving nutrition, 

promoting physical activity, and making 

changes in behavior can lower risk factors 

for type 2 diabetes in children from 42 middle 

schools across the country. Participating 

schools are randomly assigned to a program 

group, which implements the changes, or 

to a comparison group, which continues to 

offer food choices and physical education 

programs typically found in middle schools 

13 Diabetes Overview 
across the country. Students in the program 

group will have healthier choices available in 

the cafeteria and vending machines; longer, 

more intense periods of physical activity; and 

activities and awareness campaigns that promote long-term healthy behaviors. Results 

from the HEALTHY study are expected in 

2009. 

Preventing and Treating CVD in 

People with Type 2 Diabetes 

CVD is the main killer of people with type 2 

diabetes. For this reason, the NIH is studying the best strategies to prevent and treat 

CVD in people with diabetes in three major 

studies. These studies are all joint efforts of 

the NIDDK and the National Heart, Lung, 

and Blood Institute (NHLBI). 

The Look AHEAD (Action for Health in 

Diabetes) trial is the largest clinical trial 

to date to examine the long-term health 

effects of voluntary weight loss. This multicenter, randomized clinical trial is studying 

the effects of a lifestyle inter vention designed 

to achieve and maintain weight loss over the 

long-term through decreased caloric intake 

and increased exercise. Look AHEAD will 

focus on the disorder most associated with 

being overweight or obese, type 2 diabetes, 

and on the outcome that causes the greatest 

morbidity and mortality in people with type 2 

diabetes, CVD. Results after 1 year of the 

study show that people receiving the lifestyle 

intervention lost an average of 8.6 percent 

of their initial body weight. In addition, they 

showed improved control of diabetes as well 

as improvements in cardiovascular risk factors, such as high blood pressure and blood 

fat levels. 

The Action to Control Cardiovascular 

Risk in Diabetes (ACCORD) trial, a 

multicenter, randomized trial, is studying 

three approaches to preventing major 

cardiovascular events in individuals with 

type 2 diabetes. ACCORD was designed 

to compare current practice guidelines 

with more intensive glycemic control in 

10,000 individuals with type 2 diabetes, 

including those at especially high risk 

for cardiovascular events because of age, 

evidence of subclinical atherosclerosis, 

or existing clinical CVD. More intensive 

control of blood pressure than is called for 

in current guidelines and a medication to 

reduce triglyceride levels and raise HDL, or 

“good,” cholesterol levels will also be studied 

in subgroups of these 10,000 volunteers. 

Each treatment strategy will be accompanied 

by standard advice regarding lifestyle 

choices, including diet, physical activity, 

and smoking cessation, appropriate for 

individuals with diabetes. 

The primary outcome to be measured is 

the first occurrence of a major cardiovascular event, specifically heart attack, stroke, or 

cardiovascular death. In addition, the study 

will investigate the impact of the treatment 

strategies on other cardiovascular outcomes; 

total mortality; limb amputation; eye, kidney, 

or nerve disease; health-related quality of 

life; and cost-effectiveness. 

In February 2008, the NHLBI decided to stop 

one part of the study—the intensive glycemic 

control treatment—before the end of the 

entire trial because of safety concerns. However, the trial will continue with the other 

treatments until the planned end in 2009. 

The Bypass Angioplasty Revascularization 

Investigation 2 Diabetes (BARI 2D) trial, 

a 5-year, multicenter clinical trial, is 

comparing medical versus early surgical 

management of patients with type 2 diabetes 

who also have coronary artery disease and 

stable angina or ischemia. At the same 

time, BARI 2D will study the effect of 

two different strategies to control blood 

glucose—providing insulin versus increasing 

the sensitivity of the body to insulin—on 

the risk of cardiovascular mortality and 

morbidity. 

14 Diabetes Overview 
Participants in clinical trials can play a 

more active role in their own health care, 

gain access to new research treatments 

before they are widely available, and help 

others by contributing to medical research. 

For information about current studies, visit 

www.ClinicalTrials.gov. 

Points to Remember 

What is diabetes? 

• 	 a disorder of metabolism—the way 

the body uses or converts food for 

energy and growth 

What are the main types of diabetes? 

• 	type 1 diabetes 

• 	type 2 diabetes 

• gestational diabetes 

What is the impact of diabetes? 

• It affects 23.6 million people— 

7.8 percent of the U.S. population. 

• 	It is a leading cause of death and 

disability. 

• 	It costs $174 billion per year. 

Who gets diabetes? 

• 	 people of any age 

• 	 people with a family history of 


diabetes
 

• 	others at high risk for type 2 diabetes: older people, overweight and 

sedentary people, African Americans, Alaska Natives, American 

Indians, Asian Americans, Native 

Hawaiians, some Pacific Islander 

Americans, and Hispanics/Latinos 

For More Information 

To learn more about type 1, type 2, and 

gestational diabetes, as well as diabetes 

research, statistics, and education, contact 

National Diabetes Education Program 

1 Diabetes Way 

Bethesda, MD 20814–9692 

Phone: 1–888–693–NDEP 

 (1–888–693–6337) 

TTY: 1–866–569–1162 

Fax: 703–738–4929 

Email: ndep@mail.nih.gov 

Internet: www.ndep.nih.gov 

www.yourdiabetesinfo.org 

American Diabetes Association 

1701 North Beauregard Street 

Alexandria, VA 22311 

Phone: 1–800–DIABETES 

 (1–800–342–2383) 

Email: AskADA@diabetes.org 

Internet: www.diabetes.org 

Juvenile Diabetes Research Foundation 

International 

26 Broadway, 14th Floor 

New York, NY 10004 

Phone: 1–800–533–CURE 

 (1–800–533–2873) 

Email: info@jdrf.org 

Internet: www.jdrf.org 

Acknowledgments 

Publications produced by the Clearinghouse 

are carefully reviewed by both NIDDK scientists and outside experts. 

15 Diabetes Overview 
You may also find additional information about this 

topic by visiting MedlinePlus at www.medlineplus.gov. 

This publication may contain information about 

medications. When prepared, this publication 

included the most current information available. 

For updates or for questions about any medications, 

contact the U.S. Food and Drug Administration tollfree at 1–888–INFO–FDA (1–888–463–6332) or visit 

www.fda.gov. Consult your health care provider for 

more information. 

The U.S. Government does not endorse or favor any 

specific commercial product or company. Trade, 

proprietary, or company names appearing in this 

document are used only because they are considered 

necessary in the context of the information provided. 

If a product is not mentioned, the omission does not 

mean or imply that the product is unsatisfactory. 

National Diabetes 

Information Clearinghouse 

1 Information Way 

Bethesda, MD 20892–3560 

Phone: 1–800–860–8747 

TTY: 1–866–569–1162 

Fax: 703–738–4929 

Email: ndic@info.niddk.nih.gov 

Internet: www.diabetes.niddk.nih.gov 

The National Diabetes Information 

Clearinghouse (NDIC) is a service of the 

National Institute of Diabetes and Digestive 

and Kidney Diseases (NIDDK). The 

NIDDK is part of the National Institutes of 

Health of the U.S. Department of Health 

and Human Services. Established in 1978, 

the Clearinghouse provides information 

about diabetes to people with diabetes and 

to their families, health care professionals, 

and the public. The NDIC answers inquiries, 

develops and distributes publications, and 

works closely with professional and patient 

organizations and Government agencies to 

coordinate resources about diabetes. 

This publication is not copyrighted. The Clearinghouse 

encourages users of this publication to duplicate and 

distribute as many copies as desired. 

This publication is available at 

www.diabetes.niddk.nih.gov. 

U.S. DEPARTMENT OF HEALTH 

AND HUMAN SERVICES 

National Institutes of Health 

NIH Publication No. 09–3873 

November 2008 

The NIDDK prints on recycled paper with bio-based ink.