What Are Type 2 Diabetes: Causes and Symptoms?

Type 2 is the most common form of diabetes, accounting for over 90% of all diabetes cases.

The number of adults diagnosed with diabetes in the US has risen significantly in the past 30 years, almost quadrupling from 5.5 million cases in 1980 to 21.3 million in 2012.

Type 2 diabetes used to be known as adult-onset diabetes and noninsulin-dependent diabetes mellitus (NIDDM), but the disease can have an onset at any age, increasingly including childhood.

What is type 2 diabetes?

Type 2 diabetes mellitus most commonly develops in adulthood and is more likely to occur in people who are overweight and physically inactive.3

Unlike type 1 diabetes which currently cannot be prevented, many of the risk factors for type 2 diabetes can be modified. For many people, therefore, it is possible to prevent the condition.

The International Diabetes Foundation highlight four symptoms that signal the need for diabetes testing:

  • Frequent urination
  • Weight loss
  • Lack of energy
  • Excessive thirst.

To learn more, visit the Knowledge Center articles about symptoms or diagnosis.

Causes of type 2 diabetes

Insulin resistance is usually the precursor to type 2 diabetes – a condition in which more insulin than usual is needed for glucose to enter cells. Insulin resistance in the liver results in more glucose production while resistance in peripheral tissues means glucose uptake is impaired.

Obese male abdomen.
Obesity can lead to insulin resistance – often the precursor to the development of type 2 diabetes.

The impairment stimulates the pancreas to make more insulin but eventually the pancreas is unable to make enough to prevent blood sugar levels from rising too high.

Genetics plays a part in type 2 diabetes – relatives of people with the disease are at a higher risk, and the prevalence of the condition is higher in particular among Native Americans, Hispanic and Asian people.

Obesity and weight gain are important factors that lead to insulin resistance and type 2 diabetes, with genetics, diet, exercise and lifestyle all playing a part. Body fat has hormonal effects on the effect of insulin and glucose metabolism.

Once type 2 diabetes has been diagnosed, health care providers can help patients with a program of education and monitoring, including how to spot the signs of hypoglycemia, hyperglycemia and other diabetic complications.

As with other forms of diabetes, nutrition and physical activity and exercise are important elements of the lifestyle management of the condition.

For more information on how type 1 and type 2 diabetes compare, read our article: the difference between type 1 and type 2 diabetes.