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Symptoms and Signs of Type 2 Diabetes

Doctor's Notes on Type 2 Diabetes

Type 2 diabetes is a chronic condition in which there is an elevated level of sugar (glucose) in the bloodstream due to the body's inability to properly respond to insulin. Insulin is a hormone produced in the pancreas that allows the body to utilize glucose for energy. Elevated blood glucose levels are called hyperglycemia. Type 2 diabetes is different from type 1 diabetes, a condition in which the body is unable to produce enough insulin.

Early symptoms of type 2 diabetes in some people who do not know they have the disease may include erectile dysfunction, blurred vision, or numbness, tingling, or pain in the extremities. Symptoms of poorly controlled or undiagnosed 2 diabetes include frequent urination, thirst, dehydration, weight loss, fatigue, nausea, vomiting, frequent or slow healing skin sores, frequent infections, kidney infections, or urinary tract infections (UTIs).

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019

Type 2 Diabetes Symptoms

Symptoms and signs of type 1 and type 2 diabetes can be similar. Symptoms and signs of poorly controlled diabetes (or undiagnosed diabetes) can include:

Other symptoms, while characteristic of the complications that arise from long-term untreated or poorly-treated diabetes, may be the initial symptoms in some people who do not know they have diabetes. These symptoms include

Type 2 Diabetes Causes

Type 2 diabetes is the result of the body not being able to effectively use insulin, and is referred to as insulin resistance. Because patients with type 2 diabetes can still produce insulin even though the body does not respond properly, blood levels of insulin can become elevated in some people with the condition. In some, the pancreas may not be able to properly release insulin that is produced.

Risk factors for type 2 diabetes

  • Genetics is a strong risk factor for the development of type 2 diabetes. Those who have relatives with the condition are at greater risk.
  • Obesity is another major risk factor. There is a direct relationship between the severity of obesity and the likelihood of getting type 2 diabetes. This is also true for children and teens.
  • Distribution of body fat: Storing excess body fat around the waist is linked to a higher risk than storing fat in the hips and thighs.
  • Age is a risk factor for type 2 diabetes. The incidence increases with advancing age. There is an increase in type 2 diabetes with each decade over the age of 40, independent of weight.
  • Ethnicity: Certain racial and ethnic groups are more likely than others to develop type 2 diabetes. In particular, type 2 diabetes is most likely to occur in Native Americans (affecting 20%-50% of the population). It is also more common in African Americans, Hispanics/Latinos, and Asian Americans than in Caucasian Americans.
  • Gestational diabetes: Women who had diabetes during pregnancy (gestational diabetes) are at increased risk for subsequently developing type 2 diabetes.
  • Sleep disorders: Untreated sleep disorders, particularly sleep apnea, are associated with an increased risk for type 2 diabetes.
  • Inactivity: Being physically active decreases the chance of getting type 2 diabetes.
  • Polycystic ovary syndrome (PCOS): Women with this condition have an increased likelihood of developing type 2 diabetes.

Type 2 Diabetes Diagnosis, Treatment, Medication Slideshow

Type 2 Diabetes Diagnosis, Treatment, Medication Slideshow

Type 2 diabetes can affect all people, regardless of age. Early symptoms of type 2 diabetes may be missed, so those affected may not even know they have the condition. An estimated one out of every three people within the early stages of type 2 diabetes are not aware they have it.

Diabetes interferes with the body's ability to metabolize carbohydrates for energy, leading to high levels of blood sugar. These chronically high blood sugar levels increase a person's risk of developing serious health problems.

Potential Consequences of High Blood Sugar

  • Nerve problems
  • Vision loss
  • Joint deformities
  • Cardiovascular disease
  • Diabetic coma (life-threatening)
  • Other diabetes complications from high blood pressure are listed further along in this slideshow


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.