Diabetes is a condition in which the body’s levels of blood sugar and the hormone insulin are out of balance. It is one of the most common diseases in the United States, and its numbers are constantly rising. There are three main forms of diabetes:
- Type 1, in which the body does not make enough insulin
- Type 2, in which the body does not make enough insulin or it doesn’t use the insulin properly
- Gestational (pronounced je-STEY-shuhn-ul), which occurs only during pregnancy
The NICHD is one of many federal agencies and NIH Institutes that supports research on diabetes. Although the Institute studies different aspects of all three types of diabetes, the NICHD is not the primary resource for patient information about type 1 or type 2 diabetes. The National Diabetes Information Clearinghouse at https://www.niddk.nih.gov/health-information/diabetes and the National Diabetes Education Program at http://ndep.nih.gov provide detailed patient information about type 1 and type 2 diabetes.
The patient information provided in this topic focuses on gestational diabetes.
In addition, the Research Information section of this topic describes the NICHD’s research efforts related to all three types of diabetes—type 1 diabetes (also known as juvenile diabetes), type 2 diabetes, and gestational diabetes. The Institute also studies factors that contribute to diabetes, such as obesity, and conditions that are associated with diabetes, such as polycystic ovary syndrome.
Medical or Scientific Names
- Diabetes mellitus (pronounced mell-EH-tiss)
- Gestational diabetes mellitus
Diabetes: Condition Information
What is diabetes?
Diabetes is a disease of metabolism, which is the way your body uses food for energy and growth.1 In particular, it's related to one of the food nutrients that supply energy, called carbohydrates.2 Normally, your stomach and intestines digest the carbohydrates in your food into a sugar called glucose. Glucose is your body's main source of energy. After digestion, the glucose moves into your blood to give your body energy.
To get the glucose out of your blood and into the cells of your body, your pancreas makes a hormone called insulin. If you have diabetes, either your body doesn't make enough insulin, or your cells can't use it the way they should. Instead, the glucose builds up in your blood, causing diabetes, otherwise known as high blood sugar.
Diabetes is generally divided into three categories:
- Type 1—Also known as juvenile diabetes, type 1 diabetes is a condition in which the pancreas does not make enough insulin.3
- Type 2—This develops when the body becomes resistant insulin, and as a result the pancreas can no longer make enough insulin to keep blood sugar levels in balance.3 It used to be known as adult-onset diabetes, because it was seen mainly in adults, especially older ones (age 40 and up)4. Today, many obese children are developing type 2 diabetes.
- Gestational diabetes—Also known as gestational diabetes mellitus, this is a type of diabetes that only occurs in pregnant women. If a pregnant woman develops diabetes, but she didn't have it before becoming pregnant, then she has gestational diabetes.
For information about the number of people affected by or at risk for diabetes, visit the Centers for Disease Control and Prevention website.
What are the symptoms of diabetes?
One of the key dangers of diabetes is that it often doesn’t display any symptoms at all, making it hard to diagnose until it’s severe.
Common symptoms generally include:1
- Unusual thirst
- Frequent urination
- Extreme hunger
- Irritability, mood changes
Other symptoms that can occur:
- Cuts that are difficult or slow to heal
- Tingling/numbness in hands and/or feet
- Blurred vision
- Frequent infections
For pregnant women, swelling in the hands and face and may also be symptoms of gestational diabetes.
Although the NICHD studies different aspects of all types of diabetes, the NICHD is not the primary resource for patient information about type 1 or type 2 diabetes. The National Diabetes Information Clearinghouse at https://www.niddk.nih.gov/health-information/diabetes and the National Diabetes Education Program at http://ndep.nih.gov provide detailed patient information about type 1 and type 2 diabetes, including their symptoms.
What causes diabetes?
Diabetes is a disease of metabolism, which is the way the body uses food for energy and growth.1 In particular, it's related to one of the food nutrients that supply energy, called carbohydrates.2 Normally, the stomach and intestines digest the carbohydrates in food into a sugar called glucose. Glucose is the body's main source of energy. After digestion, the glucose moves into the blood to give the body energy.
To get the glucose out of blood and into the body's cells, the pancreas makes a hormone called insulin. In diabetes, either the body doesn't make enough insulin, or the cells can't use it the way they should. Instead, the glucose builds up in the blood, causing diabetes, otherwise known as high blood sugar.
The exact causes of diabetes are not fully understood and typically involve multiple factors, such as genetics and interactions with the environment.
The majority of cases of type 1 diabetes are "sporadic" meaning there is no family history of the condition. Likewise, the rates of type 1 diabetes in both members of set of identical twins is lower than would be expected if the condition was caused by genetics alone. The environmental component is strong and could result from a combination of factors, such as exposure to viruses in the small intestine or to foreign proteins from foods at a time when the immune system of the digestive tract is too immature to process them.
Researchers leading the Trial to Reduce the Incidence of Type 1 Diabetes Mellitus in the Genetically at Risk (TRIGR), which is supported in part by the NICHD, are examining whether exposure to foreign proteins from cow's milk or cow milk-based infant formula can cause type 1 diabetes, especially in children who are at high risk for the condition based on their family history and genetic profile. The Trial aims to determine whether a nutritional intervention—feeding cow milk-based formulas that have been specially processed to remove the foreign proteins—during infancy can delay or prevent the onset of type 1 diabetes in children at high risk for the condition.
Obesity is a major factor in developing type 2 diabetes. Most Americans with type 2 diabetes are obese or overweight. Obesity reduces the body's ability to control blood sugar, so the body overproduces insulin to compensate—and a cycle develops.3
Pregnancy causes many different changes to the body, including changes to metabolism that result in gestational diabetes. These changes are usually the result of hormones produced during pregnancy that keep insulin from doing its job.
How do health care providers diagnose diabetes?
The most common test for diagnosing any kind of diabetes is a one-step approach called the oral glucose tolerance test. Prior to the test, you can’t eat or drink anything (except water) for between 4 and 8 hours. A health provider tests your initial sugar level and then gives you a sugar drink. Then your sugar level is checked every 30 to 60 minutes for up to 3 hours.1,2
Although the NICHD studies different aspects of all types of diabetes, the NICHD is not the primary resource for patient information about type 1 or type 2 diabetes. The National Diabetes Information Clearinghouse and the National Diabetes Education Program provide detailed information about type 1 and type 2 diabetes, including specific information about diagnosis and glucose levels.
Risk for type 1 diabetes
Health care providers can use a test to check for certain blood markers that can predict how likely it is that someone will develop type 1 diabetes. These blood markers signal that the immune system is attacking the beta cells of the pancreas. Having two or more of these markers, called antibodies, is associated with higher risk of developing type 1 diabetes over the next 10 years.3
Testing for gestational diabetes
Health care providers will consider a woman’s risk factors and current health before testing for gestational diabetes. If a woman is at high risk for gestational diabetes, her health care provider will test her as soon as she knows she is pregnant. If a woman is at low risk for gestational diabetes, her health care provider might not test her at all, or will test her between 24 weeks and 28 weeks of pregnancy. For more information about testing for gestational diabetes, see the NICHD’s Am I at risk for gestational diabetes? brochure.
What are the treatments for diabetes?
There are two main types of treatment for diabetes:
- Lifestyle changes—These include changing your diet to something healthier and improving your exercise/activity level. More information on lifestyle changes to control diabetes can be found at the National Diabetes Education Program.
- Medication—Oral medicines and sometimes injections with insulin may be used. For more information on medications to control diabetes, visit the National Diabetes Information Clearinghouse.
The National Diabetes Information Clearinghouse and the National Diabetes Education Program provide detailed patient information about type 1 and type 2 diabetes, including specific information about treatments.
The NICHD offers some general information about managing gestational diabetes. This information should not replace the advice and care from a health care provider.
Diabetes: NICHD Research Goals
The NICHD studies diabetes, including gestational diabetes, within the context of preventing and managing chronic disease and its long-term health effects, and of understanding the developmental origins of health and disease.
Some of the Institute’s diabetes research addresses these important goals:
- Type 1 Diabetes Mellitus (T1DM):
- Investigating treatments that can prevent or slow the onset of T1DM in those at high risk for the condition, including infants at high genetic risk
- Testing non-invasive ways to monitor children with T1DM for episodes of hypoglycemia
- Investigating a combination insulin-delivery and glucose-sensing system that can mimic normal pancreatic beta-cell function
- Understanding the genetic risk factors that lead to T1DM and detecting the earliest gene-expression changes in those genetically at high risk for the condition
- Identifying determinants of health outcomes and testing the efficacy of behavioral intervention for youth with T1DM and their families
- Type 2 Diabetes Mellitus (T2DM):
- Defining and reversing metabolic risk factors early in development that contribute to T2DM
- Identifying the genetic risk factors for T2DM and exploring treatments to prevent or stop its onset in those who are at high genetic risk
- Exploring the relationship between normal development, factors in the environment, and T2DM
- Understanding disparities in the prevalence and course of T2DM, its precursors, and its associated outcomes
- Gestational Diabetes Mellitus (GDM):
- Understanding the mechanisms of GDM
- Defining treatments and management parameters that improve health outcomes for mother and baby
- Identifying biomarkers that might indicate GDM and complications such as preeclampsia
- Examining the health effects on the baby both in the short- and long-term
- Investigating ways to improve and manage delivery of macrosomic infants
Diabetes: Research Activities and Scientific Advances
Institute Activities and Advances
The NICHD research portfolio includes sizable efforts on diabetes within the context of preventing chronic disease and of understanding the early origins of health and disease. Projects on diabetes, its risk factors, and its associated conditions and outcomes are spread across multiple organizational units and include several large international clinical studies. Some of this research is described below.
The Pediatric Growth and Nutrition Branch (PGNB) supports research on multiple aspects of type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and gestational diabetes mellitus (GDM). Research priorities include developing methods for detecting potential diabetics in childhood and for developing successful techniques of immunomodulation to prevent or mitigate the body's immune attack on the pancreatic beta cell. Branch research has also pioneered immunogenetic methods that stratify levels of risk for T1DM. In addition to projects led by individual investigators, the PGNB also supports several large, long-term clinical studies and networks in the United States and abroad. Visit the Other Activities and Advances section for details on these projects.
Besides the PGNB, other NICHD extramural and intramural research units support and conduct research on diabetes. One of these is the extramural Population Dynamics Branch (PDB), which supports research and research training in demography, reproductive health, and population health.
The Institute’s Pregnancy and Perinatology Branch (PPB) seeks to promote healthy pregnancy, labor, delivery, and infancy by supporting research on multiple topics within each of these critical development periods. PPB research addresses high-risk pregnancies that result from a variety of conditions, including gestational diabetes, as well as studies of safe delivery and neonatal health outcomes. Like the PGNB, the PPB also supports large-scale research studies and networks in addition to projects led by individual investigators.
Researchers in the Division of Intramural Population Health Research are leading multiple studies of diabetes management in adolescents. One of these studies is exploring the effectiveness of a family-focused management plan on diabetes outcomes. Another examines the effect of a program to promote healthful eating. Visit the Division’s Health Behavior Branch to learn more about these studies. In addition, the Division’s Epidemiology Branch is examining the Epidemiology, Etiology, and Health Consequences of Gestational Diabetes to address critical data gaps and to improve detection and management of the condition.
The PGNB supports multiple ongoing research trials and networks that focus on understanding diabetes. Some of these projects include:
- DirecNet , the world’s first research network devoted to studying children with T1DM
- The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study, examining the health effects of gestational diabetes in women and their offspring (Find Hyperglycemia and Adverse Pregnancy Outcomes Study PubMed Articles). With the NIDDK, the PGNB launched the HAPO Follow-up Study (HAPO-FUS) in 2013, which will measure the height, weight, blood pressure, body fat, blood sugar, insulin, and blood fats of 7,000 of the original HAPO mothers and their children, who are now 8 to 12 years old, to determine whether there is a long-term effect of the hyperglycemia during pregnancy.
- Trial to Reduce the Incidence of TIDM in the Genetically at Risk (TRIGR), the first large trials designed to ascertain if a simple nutritional intervention during infancy can delay or prevent the onset of Type 1 diabetes in children at high genetic risk of this condition. Results from a small pilot study of 230 genetically at-risk infants were highly encouraging. This research showed a 50% reduction in appearance of autoantibodies directed against the β cells of the pancreas in the group assigned to protein hydrolysate formula. These autoantibodies are used as markers of diabetes risk and appear to be involved in the attack on the β cells. (PMID: 21067382)
- TrialNet , a network of 14 diabetes centers dedicated to utilizing a four-prong paradigm to test the ability of biological agents to prevent type 1 diabetes in at-risk children, or to slow the course of the disease in newly diagnosed children
The PPB supports efforts to understand gestational diabetes, its symptoms, and its outcomes through the Maternal-Fetal Medicine Units (MFMU) Network. The MFMU Network studies various types of high-risk pregnancies and pregnancy outcomes, including gestational diabetes, preterm labor and birth, and preeclampsia.
The NICHD is also a sponsor of the Consensus Development Conference on Diagnosing GDM, which aims to better understand the benefits and risks of various GDM screening and diagnostic approaches by assessing the available scientific evidence. In 2013, the panel concluded that there is insufficient evidence that adopting a new diagnostic approach for GDM would provide more benefit than harm.