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Type 2 Diabetes
(Diabetes Mellitus Type 2; Insulin-Resistant Diabetes; Diabetes, Type 2)
Diabetes happens when the body does not make enough insulin to move glucose from the blood to the cells. This causes glucose to build up in the blood instead of being used by the cells for energy. Type 2 is more common in adults.
Type 2 happens when the body becomes resistant to insulin or when the pancreas cannot make enough. This may be due to a person's genes and habits.
Type 2 is more common in people with obesity and those over 45 years of age. People who are American Indian, Alaska natives, Black, and Hispanic are at higher risk. Some other common risks are:
- Prediabetes—slightly high glucose levels
- Metabolic syndrome—fat around the belly and high cholesterol, glucose, and blood pressure
- Polycystic ovary syndrome
- Past gestational diabetes or having a baby that weighs over 9 pounds at birth
- Poor eating habits
- Lack of exercise
- High blood pressure
- Taking certain medicines, such as glucocorticoids or thiazides
Most people do not have problems right away. Others may have:
- Urinating more often
- Being very thirsty
- Blurry eyesight
- Weight loss
- Being very tired
- Frequent infections
The doctor will ask about your symptoms and health history. A physical exam will be done.
Diabetes is diagnosed with blood tests that check for high glucose levels. More than 1 test may be done.
These blood tests will also be done to find out whether it is type 1 or type 2:
- Insulin level or C-peptide tests to see how much insulin is being made by the pancreas
- Tests that look for antibodies that are working against the pancreas
The goal is to keep glucose levels at close to normal levels. This can be done with:
Healthy habits can help manage type 2, such as:
- Testing blood glucose levels often
- Working with a dietitian to make a meal plan that will help keep blood glucose levels normal
- Getting enough exercise
- Reaching a healthy weight
Some people may need medicine to lower insulin resistance. There are many types. Metformin is a common medicine that is given.
People who cannot manage type 2 with healthy habits and medicine may need insulin. It will replace the insulin hormone that their body does not make. It can be given by injection, inhaler, or by a pump that gives it in small amounts during the day.
A person may not be able to lower the risk of diabetes. Healthy habits may help, such as exercising, staying at a healthy weight, and eating right.
American Diabetes Association
National Diabetes Information Clearinghouse
Canadian Diabetes Association
Public Health Agency of Canada
American Association of Clinical Endocrinologists, American College of Endocrinology. Comprehensive Type 2 Diabetes Management Algorithm 2017. Endocr Pract. 2017 Feb;23(2):207-238.
American Diabetes Association Classification and Diagnosis of Diabetes of Diabetes Mellitus. Diabetes Care. 2015 Jan;38 Suppl:S8-S16.
American Diabetes Association. Standards of medical care in diabetes. Diabetes Care. 2019 Jan; 42 (Suppl 1):S1-S193,
Diabetes mellitus type 2 in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/diabetes-mellitus-type-2-in-adults. Updated February 14, 2019. Accessed November 1, 2019.
Diabetes mellitus type 2 in children and adolescents. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/diabetes-mellitus-type-2-in-children-and-adolescents. Updated May 7, 2019. Accessed November 1, 2019.
Dietary considerations for patients with type 2 diabetes. EBSCO DynaMed website. Available at: https://www.dynamed.com/management/dietary-considerations-for-patients-with-type-2-diabetes. Updated March 11, 2019. Accessed November 1, 2019.
Symptoms & Causes of Diabetes. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: https://www.niddk.nih.gov/health-information/diabetes/overview/symptoms-causes. Updated December 2016. Accessed November 1, 2019.
9/16/2014 DynaMed Systematic Literature Surveillance https://www.dynamed.com/prevention/diabetes-mellitus-type-2-prevention: Zhou D, Yu H, et al. Nut consumption in relation to cardiovascular disease risk and type 2 diabetes: a systematic review and meta-analysis of prospective studies. Am J Clin Nutr. 2014;100(1):270-277.
12/14/2016 DynaMed Systematic Literature Surveillance https://www.dynamed.com/condition/risk-factors-for-diabetes-mellitus-type-2: Shen HN, Yang CC, et al. Risk of diabetes mellitus after first-attack acute pancreatitis: a national population-based study. Am J Gastroenterol. 2015;110(12):1698-1706.
10/1/2018 DynaMed Systematic Literature Surveillance https://www.dynamed.com/condition/risk-factors-for-diabetes-mellitus-type-2 : Mantovani A, Byrne CD, et al. Nonalcoholic fatty liver disease and risk of incident type 2 diabetes: a meta-analysis. Diabetes Care. 2018;41(2):372-382.
- Reviewer: EBSCO Medical Review Board Daniel A. Ostrovsky, MD
- Review Date: 09/2019
- Update Date: 07/28/2020