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What Is Type 2 Diabetes?

Type 2 diabetes, which used to be called adult-onset or non insulin-dependent diabetes, results when the body doesn’t produce enough insulin or is unable to use insulin properly (a condition called insulin resistance). This is the most common form of diabetes, accounting for 90%-95% of all cases. It usually occurs in people who are over 40, overweight, and have a family history of the disease although it is also becoming more common in younger people, particularly adolescents.

Research indicates that type 2 diabetes is caused by a combination of environmental and genetic factors. Many risk factors make people more likely to develop the disease including obesity, high cholesterol, high blood pressure and physical inactivity. Type 2 diabetes is more common among Native Americans, African Americans, Latinos and Asian Americans/Pacific Islanders. Also, people who develop diabetes while pregnant (a condition called gestational diabetes) are more likely to develop type 2 diabetes later in life, as are people with prediabetes or the metabolic syndrome – two diseases that are closely related to type 2 diabetes.

Type 2 Diabetes Research

People who live with type 2 diabetes must monitor their blood glucose and be sure to keep it in a healthy range through a combination of diet and physical activity. Their doctors may prescribe medications to decrease insulin resistance and although their bodies can still produce some insulin, they may also need to take an additional dosage. In any case, keeping blood glucose as close to normal as possible is very important because poor glucose control is associated with an increased risk of serious complications including damage to blood vessels (vascular complications) which may lead to eye, heart and kidney disease.

Type 2 Diabetes Research Focuses on Four Main Areas:

Prediction and prevention of the disease through lifestyle modification and medications – especially because it may develop very slowly over time;

  • Education and health service programs that ensure patients know everything they need to do to manage the disease;
  • New technology and medications to combat insulin resistance and help patients regulate blood glucose, evaluated through clinical trials;

Joslin Researchers Are Searching for Answers

  • Who is at risk for type 2 diabetes and what are the first signs of the disease?
  • Is there a way to reverse insulin resistance and restore insulin sensitivity?
  • What physical differences exist between people with type 2 diabetes and those without? Why does it tend to run in families?
  • What new technologies make diabetes management easier for patients?

Most Commonly Used Terms


Insulin resistance: condition in which cells no longer respond well to insulin. The body responds by secreting more insulin into the bloodstream in an effort to reduce blood glucose levels. Exercise, weight loss and certain medications may reduce insulin resistance.

Insulin sensitivity: the opposite of insulin resistance. It is the degree to which cells respond to a particular dose of insulin by lowering blood glucose levels.


Metabolic syndrome: cluster of conditions (also known as syndrome X) that increase the risk of heart disease, classified by three or more of the following: abdominal obesity, high cholesterol or triglycerides, high blood pressure and high blood glucose.

Prediabetes: higher than normal fasting blood glucose level that is not yet high enough to be classified as diabetes.

Clinical trials: carefully controlled studies that are conducted to test the effectiveness and safety of new drugs, medical products or techniques. All drugs in the U.S. undergo three phases of clinical trials before being approved for general use


Page last updated: September 01, 2015