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What Is Diabetes Mellitus?

Diabetes mellitus logoDiabetes mellitus (often referred to as simply diabetes) is a chronic metabolic disorder, which can be generally described as having high blood sugar levels due to insufficient amount of insulin produced by the body or insufficient response of human cells to insulin. From Greek, “diabetes” means “passing though”, which refers to one of the main diabetes symptoms – excessive urine. “mellitus” means “sweet as honey”; this refers to sugar in urine, which is normally absent in healthy human urine.

The main types of diabetes are:

There are also other forms of diabetes mellitus. For more information, read the “Types of Diabetes”, “Juvenile Diabetes”, and “Gestational Diabetes”.

Diabetes mellitus affects all types of human metabolism – carbohydrate, lipid, protein, mineral, and water-salt exchanges. This disease often leads to uncontrolled weight loss, increases the risk of cardiovascular and renal disorders, and thus requires treatment and constant control. Without proper treatment, a person with diabetes dies.

Sugar, Insulin, and Diabetes. Why It Happens and How

Carbohydrates are essential for normal metabolism. People get carbohydrates from almost everything they eat. In the process of digestion, carbohydrates are split into the simplest form of sugars – glucose. Thus glucose is the principal carbohydrate for the whole human organism. For many organs and tissues, glucose is the only possible source of energy.

To use glucose as fuel, almost all organs and tissues need a special helper – insulin. Insulin is a hormone produced by the β-cells of pancreas into the blood. When the blood sugar levels rise, the pancreas starts releasing more insulin to help the cells absorb glucose and use it for energy, or to store the excess amounts of glucose in the form of glycogen. In such a way, insulin constantly keeps the general glucose levels normal.

Diabetes mellitus appears due to absolute (when there is not enough insulin in blood to cope with all of the received glucose – type 1 diabetes mellitus) or relative (when the body cells fail to properly react on insulin – type 2 diabetes mellitus) insulin deficiency. When this happens, the biggest part of organs and tissues do not get enough energy, while the excess sugar remains in blood causing hyperglycemia – the condition of abnormally high blood sugar levels, and other metabolic problems. This is the reason why people with diabetes lose weight though consuming much food. Next, when the glucose levels are higher than 10 mmol/L, the kidneys remove it into urine. Glucose in urine increases the osmotic pressure of the urine, which results in increased thirst, frequent urination, and general body dehydration.

Diabetes and Heredity

It has been proven that there exists a genetic predisposition to diabetes though a number of statistical and later genetic studies. The genome of those having diabetes usually possesses a number of genetic variations. For example, the presence of both B8 and B15 in one genome increase the risk of having diabetes mellitus in 10 times, and the presence of Dw3/DRw4 markers increases this risk in 9,4 times.

One may have predisposition to type 1 diabetes mellitus if someone in the family suffers from an autoimmune disease, not necessarily diabetes. In such patients, some virus infections may trigger appearance of antibodies to pancreas β-cells, which produce insulin. Main diabetes symptoms become noticeable only when more than 80% of β-cells have been ruined. Usually, it takes from several weeks to several years for the disease to become evident. There is a 3-7% chance of maternally inheriting and 10% chance of paternally inheriting type 1 diabetes mellitus. And if both parents have this kind of disease, the risk rises up to 70%.

Concerning type 2 diabetes mellitus, it appears due to the congenital (i.e. inherited) insulin resistance, which is the condition when body cells do not respond to insulin. There is an 80% chance of inheriting type 2 diabetes mellitus, either maternally or paternally. If both parents suffer from non-insulin-dependent diabetes, the chances of having the same disease make almost 100%.

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