Diabetes is a long-term (chronic) disease in which the body cannot regulate the amount of sugar in the blood.
Diabetes - type 1; Diabetes - type 2; Diabetes - gestational; Type 1 diabetes; Type 2 diabetes; Gestational diabetes; Diabetes mellitus
Insulin is a hormone produced by the pancreas to control blood sugar. Diabetes can be caused by too little insulin, resistance to insulin, or both.
To understand diabetes, it is important to first understand the normal process by which food is broken down and used by the body for energy. Several things happen when food is digested and absorbed:
People with diabetes have high blood sugar because their body cannot move sugar from the blood into muscle and fat cells to be burned or stored for energy, and/or because their liver makes too much glucose and releases it into the blood. This is because either:
There are two major types of diabetes. The causes and risk factors are different for each type:
Gestational diabetes is high blood sugar that develops at any time during pregnancy in a woman who does not already have diabetes.
If your parent, brother, or sister has diabetes, you may be more likely to develop the disease.
A high blood sugar level can cause several symptoms, including:
Because type 2 diabetes develops slowly, some people with high blood sugar have no symptoms.
Symptoms of type 1 diabetes develop over a short period. People may be very sick by the time they are diagnosed.
After many years, diabetes can lead to other serious problems. These problems are known as diabetes complications, and include:
A urine analysis may show high blood sugar. But a urine test alone does not diagnose diabetes.
Your health care provider may suspect that you have diabetes if your blood sugar level is higher than 200 mg/dL (11.1 mmol/L). To confirm the diagnosis, one or more of the following tests must be done.
Screening for type 2 diabetes in people who have no symptoms is recommended for:
Type 2 diabetes can sometimes be reversed with lifestyle changes, especially losing weight with exercise and by eating healthier foods. Some cases of type 2 diabetes can also be improved with weight loss surgery.
There is no cure for type 1 diabetes (except for a pancreas or islet cell transplant).
Treating either type 1 diabetes or type 2 diabetes involves nutrition, activity and medicines to control blood sugar level.
Everyone with diabetes should receive proper education and support about the best ways to manage their diabetes. Ask your provider about seeing a certified diabetes educator (CDE).
Getting better control over your blood sugar, cholesterol, and blood pressure levels helps reduce the risk for kidney disease, eye disease, nervous system disease, heart attack, and stroke.
To prevent diabetes complications, visit your provider at least 2 to 4 times a year. Talk about any problems you are having. Follow your provider's instructions on managing your diabetes.
Many resources can help you understand more about diabetes. If you have diabetes, you can also learn ways to manage your condition and prevent diabetes complications.
Diabetes is a lifelong disease for most people who have it.
Tight control of blood glucose can prevent or delay diabetes complications. But these problems can occur, even in people with good diabetes control.
After many years, diabetes can lead to serious health problems:
Keeping an ideal body weight and an active lifestyle may prevent or delay the start of type 2 diabetes. If you're overweight, losing just 5% of your body weight can reduce your risk. Some medicines can also be used to delay or prevent the start of type 2 diabetes.
At this time, type 1 diabetes cannot be prevented. But there is promising research that shows type 1 diabetes may be delayed in some high risk people.
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Atkinson MA, McGill DE, Dassau E, Laffel L. Type 1 diabetes mellitus. In: Melmed S, Auchus, RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 36.
Riddle MC, Ahmann AJ. Therapeutics of type 2 diabetes mellitus. In: Melmed S, Auchus, RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 35.
US Preventive Services Task Force, Davidson KW, Barry MJ, Mangione CM, et al. Screening for prediabetes and type 2 diabetes: US Preventive Services Task Force recommendation statement. JAMA. 2021;326(8):736-743. PMID: 34427594 pubmed.ncbi.nlm.nih.gov/34427594/.
Reviewed By: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.