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Diabetes is a chronic condition marked by high levels of glucose in the blood. It is caused either by the inability to produce insulin (a hormone produced by the pancreas to control blood glucose levels) or by the body not being able to use insulin effectively.

The main types of diabetes are:

  • Type 1 diabetesa lifelong autoimmune disease that usually has onset in childhood but can be diagnosed at any age
  • Type 2 diabetesusually associated with lifestyle factors and largely preventable
  • Gestational diabeteswhen higher-than-normal blood glucose is diagnosed in pregnancy.

Type 1 diabetes

Type 1 diabetes is an unpreventable autoimmune disease that develops when the immune system destroys the insulin-producing cells of the pancreas. The absence of insulin means glucose cannot be transported into the cells (where it would usually be stored for future energy use) and consequently blood glucose levels rise. The exact cause of type 1 diabetes is unknown, although it is believed to be an interaction of genetic predisposition and environmental factors. Although type 1 diabetes can occur at any age, it mainly develops during childhood and adolescence. Insulin replacement is essential for survival and, except in cases where a pancreatic transplant occurs, insulin will be required every day throughout a person's life.

Type 2 diabetes

Type 2 diabetes is the most common form of diabetes, and is largely preventable by maintaining a healthy lifestyle. It occurs when the body becomes resistant to the insulin being produced by the pancreas and/or the amount produced is inadequate to meet the body's needs. Insulin is often used in the treatment of type 2 diabetes, but not in all cases. When first diagnosed with type 2 diabetes, blood glucose levels can often be maintained at normal levels through lifestyle modification and/or oral glucose lowering medication, although insulin may eventually be required as the condition progresses. Modifiable risk factors for type 2 diabetes include physical inactivity, unhealthy diet, obesity, tobacco smoking, high blood pressure and high blood lipids.

Gestational diabetes

Gestational diabetes is a form of diabetes that involves high blood sugar levels appearing for the first time during pregnancy, generally in the second or third trimester, among women who have not previously been diagnosed with other forms of diabetes. It can result in complications for mother and baby. While gestational diabetes may resolve after the baby is born, it can recur in later pregnancies and greatly increases the risk that both the mother and the baby may develop type 2 diabetes later in life. Some women can manage their gestational diabetes by changes to diet and exercise, while others require insulin treatment.