Causes & Risk Factors

Family history and lifestyle can play an important part in the development of Type 2 diabetes. Some of the most important factors include weight, inactivity, age, race, and for women, developing gestational diabetes during pregnancy.


Type 2 diabetes develops when the body becomes resistant to insulin or when the pancreas stops producing enough insulin. Exactly why this happens is unknown, although genetics and environmental factors, such as excess weight and inactivity, seem to be contributing factors.

How insulin works

Insulin is a hormone that comes from the gland situated behind and below the stomach (pancreas).

  • The pancreas secretes insulin into the bloodstream.
  • The insulin circulates, enabling sugar to enter your cells.
  • Insulin lowers the amount of sugar in your bloodstream.
  • As your blood sugar level drops, so does the secretion of insulin from your pancreas.

The role of glucose

Glucose — a sugar — is a main source of energy for the cells that make up muscles and other tissues.

  • Glucose comes from two major sources: food and your liver.
  • Sugar is absorbed into the bloodstream, where it enters cells with the help of insulin.
  • Your liver stores and makes glucose.
  • When your glucose levels are low, such as when you haven't eaten in a while, the liver breaks down stored glycogen into glucose to keep your glucose level within a normal range.

In Type 2 diabetes, this process doesn't work well. Instead of moving into your cells, sugar builds up in your bloodstream. As blood sugar levels increase, the insulin-producing beta cells in the pancreas release more insulin, but eventually these cells become impaired and can't make enough insulin to meet the body's demands.

In the much less common Type 1 diabetes, the immune system destroys the beta cells, leaving the body with little to no insulin.

Risk factors

Researchers don't fully understand why some people develop Type 2 diabetes and others don't. It's clear, however, that certain factors increase the risk, including:

  • Weight. Being overweight is a primary risk factor for Type 2 diabetes. The more fatty tissue you have, the more resistant your cells become to insulin. However, you don't have to be overweight to develop Type 2 diabetes.
  • Fat distribution. If your body stores fat primarily in your abdomen, your risk of Type 2 diabetes is greater than if your body stores fat elsewhere, such as your hips and thighs.
  • Inactivity. The less active you are, the greater your risk of Type 2 diabetes. Physical activity helps you control your weight, uses up glucose as energy and makes your cells more sensitive to insulin.
  • Family history. The risk of Type 2 diabetes increases if your parent or sibling has Type 2 diabetes.
  • Race. Although it's unclear why, people of certain races — including blacks, Hispanics, American Indians and Asian Americans — are more likely to develop Type 2 diabetes than whites are.
  • Age. The risk of Type 2 diabetes increases as you get older, especially after age 45. That's probably because people tend to exercise less, lose muscle mass and gain weight as they age. But Type 2 diabetes is also increasing dramatically among children, adolescents and younger adults.
  • Prediabetes. Prediabetes is a condition in which your blood sugar level is higher than normal, but not high enough to be classified as diabetes. Left untreated, prediabetes often progresses to Type 2 diabetes.
  • Gestational diabetes. If you developed gestational diabetes when you were pregnant, your risk of developing Type 2 diabetes increases. If you gave birth to a baby weighing more than 9 pounds (4 kilograms), you're also at risk of Type 2 diabetes.
  • Polycystic ovarian syndrome. For women, having polycystic ovarian syndrome — a common condition characterized by irregular menstrual periods, excess hair growth and obesity — increases the risk of diabetes.

This article is from the Mayo Clinic Health Information Library and is legally licensed through the NewsCred publisher network. Please direct all licensing questions to legal@newscred.com.

Causes & Risk Factors

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Causes & Risk Factors

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Prevention

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Symptoms & Diagnosis

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Complications

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Treatment

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Coping & Support

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