No, type 2 diabetes mellitus (T2DM) is not an autoimmune disease.

The term autoimmune disease describes when the immune system attacks and damages healthy cells in the body by mistake. Although some research suggests that the immune system may play a role in the development of T2DM, most health experts classify it as a chronic metabolic disorder. This describes conditions that affect any aspect of metabolism.

Conversely, unlike T2DM, type 1 diabetes mellitus (T1DM) is an autoimmune disease. Health experts consider T1DM an autoimmune condition because it occurs when the body’s immune system mistakenly attacks and destroys the beta cells in the pancreas, which are responsible for producing insulin.

T2DM happens when the body cannot use insulin effectively and the cells in the body eventually develop insulin resistance, or impaired insulin sensitivity.

This causes insulin to be less effective. As a result, more insulin is necessary to enable cells to use glucose in the blood. Over time, this can cause the beta cells in the pancreas to wear out. Eventually, the pancreas is no longer able to produce enough insulin to overcome the cells’ resistance. This leads to higher blood glucose levels, and ultimately T2DM.

While researchers do not fully understand what causes problems with insulin production and resistance, risk factors for T2DM can include:

  • having obesity
  • being 35 or older
  • a family history of T2DM or personal history of gestational diabetes
  • not being physically active
  • smoking
  • having prediabetes
  • being African American, American Indian, Asian American, Hispanic, Latino, or Pacific Islander