Diabetes is a chronic disease characterized by raised glucose levels in the blood (hyperglycaemia) which occurs when insulin is not produced in the right amounts or is not used effectively. Insulin is a hormone made in the pancreas which allows glucose to enter cells, where it can be used as a source of energy. When this mechanism is disrupted, glucose accumulates in the bloodstream.
Type 1 diabetes
It accounts for about 10% of all diabetes cases and usually appears in childhood or adolescence. Type 1 diabetes is characterized by a lack of insulin secretion due to the destruction of insulin-producing ß cells in the pancreas, which results in patients requiring daily injections of this hormone for the rest of their lives. The rate of ß-cell destruction (and therefore the development of the disease) is quite variable, typically being rapid in children and adolescents and slower in adults (this rare form is usually referred to as Latent Autoimmune Diabetes in Adults, or LADA).
Type 1 diabetes is classified as an “autoimmune” disease, as it involves an abnormal immune response directed against the patient’s own organs. Various viruses have been proposed as potential triggers of this immune response, including cytomegalovirus, Coxsackie B viruses, the encephalomyocarditis virus and those responsible for parotitis (commonly known as "mumps"). Other non-infectious triggers are being studied, such as substances present in milk.
Type 2 diabetes
It is the most common form of diabetes and accounts for about 90% of all diabetes cases. In type 2 diabetes, the body’s cells are unable to effectively use insulin produced by the pancreas, but the cause of this condition is still unclear. The disease usually occurs in people over 30-40 years of age, and several risk factors have been associated with its development, including: family history of diabetes, physical inactivity, overweight and ethnicity. About 40% of people with type 2 diabetes have first-degree relatives (parents, siblings) with the same disease, and concordance rates among monozygotic twins are close to 100%, which suggests a strong hereditary component to this type of diabetes.
Rare forms of type 2 diabetes, referred to as MODY (Maturity Onset Diabetes of the Young), are characterized by an early onset of the disease and associated with rare genetic defects affecting intracellular mechanisms of insulin action.
Gestational diabetes is diagnosed when high blood glucose levels are detected for the first time during pregnancy. It occurs in about 4% of all pregnancies. Treatment can involve only dietary changes or also insulin injections, and entails more frequent medical checks for both the pregnant woman and her unborn baby.