What is diabetes?Diabetes mellitus is a chronic condition which is characterized by increased blood glucose levels (hyperglycemia), due to the relative or absolute insulin deficiency in the context of insulin resistance (inability of the body tissues to properly respond to insulin signalling). How many types of diabetes do exist? There are three main types of diabetes, type 1 diabetes (T1DM), type 2 diabetes (T2DM) and gestational diabetes (GDM). There are also other less common types of diabetes which include monogenic diabetes and secondary diabetes.
What is type 1 diabetes (T1DM)?T1DM is an autoimmune disease in which the insulin secreting β-cells are gradually destroyed, resulting in none to very little insulin secretion. T1DM usually develops and therefore is diagnosed during childhood or adolescence. These patients are lifelong insulin dependent in order to maintain glucose homeostasis.
What is type 2 diabetes (T2DM)?In T2DM, hyperglycemia is the result of insulin resistance which primarily leads to hyperinsulinemia in order to lower the rise in blood glucose levels. Gradually, a relative inadequate production of insulin may develop. It is more common for T2DM to be detected in older adults, although the prevalence of the disease in children and adolescents is continuously rising due to the growing levels of obesity, physical inactivity and poor dietary habits.
What is gestational diabetes (GDM)?GDM is a type of diabetes that affects pregnant women usually during the second and third trimester of pregnancy though it can occur at any time during pregnancy. In some women, diabetes may be diagnosed within the first trimester of pregnancy. However, in most of these cases diabetes likely existed before pregnancy. Pregnant women with hyperglycemia can have high blood pressure or fetal macrosomia, which increase the risk of pregnancy complications.
Source: IDF atlas 2017
What is the prevalence of T2DM?
- Based on the IDF Atlas 2017, the prevalence of T2DM has substantially increased worldwide.
- Comparing the results of the IDF Atlas 2017 to the ones published in the IDF Atlas of 2000, a noticeable rise in the prevalence of T2DM can be observed in all of the IDF regions.
How is diabetes diagnosed?According to the current criteria from the World Health Organization (WHO), T2DM is diagnosed when blood glucose levels are elevated. There are various tests and measurements with specific cut-off values that need to be carried out in order to diagnose T2DM. All available methods are presented in the table below.
- Fasting plasma glucose should be measured in the morning after an overnight fast.
- The same requirement applies to the Oral Glucose Tolerance Test (OGTT), which is a two-hour plasma glucose test following a 75g oral glucose load.
- Random plasma glucose can be measured any time of the day independently of what has been consumed previously.
- Glycosylated haemoglobin A1C (HbA1c %) appears in the bloodstream when glucose is bound to haemoglobin, which is the protein that carries oxygen in the red blood cells (RBCs). This measurement
- indicates the mean blood glucose levels of the past 2 to 3 months, since the average lifespan of the RBCs is 120 days.
Which are the main complications of diabetes?Diabetes complications can be divided into two large groups∙ acute and chronic complications. Acute complications include:
- Diabetic ketoacidosis (DKA)
- Hyperglycaemic hyperosmolar state (HHS)
- Hyperglycaemic diabetic coma
- Seizures / loss of consciousness
- Coronary artery disease (CAD) [angina, myocardial infarction]
- Peripheral artery disease (PAD) [stroke, diabetic encephalopathy, diabetic foot].
- Increased rates of cancer
- Physical and cognitive disability
Source: IDF atlas 2017