Diabetes mellitus refers to a large group of endocrine disorders related to disturbances in carbohydrate metabolism and is characterized by chronic hyperglycemia (elevated blood glucose levels).

Diabetes mellitus (DM) is a very serious disease, dangerous because of its complications that affect almost all organs and systems of the body. According to WHO data, it ranks 6th among the causes of mortality, with 1.5 million people dying annually from DM, and the number of diagnosed patients exceeding 400 million and increasing every year.

DM not only shortens the lifespan of those affected and reduces their quality of life but also places a heavy financial burden on both the patient and the healthcare and social protection systems. More than 12% of healthcare expenditures worldwide are related to DM. This is why the issue of diabetes prevention and the prevention of complications is very important. Globally, special attention is now being paid to this issue, and methods for early diagnosis, prevention, and treatment of various types of DM are being developed.

What Happens in the Body with Diabetes
The effectiveness of a diabetes prevention program depends not only on doctors but primarily on patients, on their understanding of the proposed rules and methods, and on their conscious and disciplined adherence to the doctor’s recommendations.

For this, it is important that every patient at risk knows and understands what this disease is, the types and forms of this disease, what contributes to its development, and what it can lead to. This knowledge will help prevent diabetes, and if symptoms have already appeared, to stop or slow down its progression and prevent complications.

To achieve this, it is first necessary to explain how glucose works in the body and why its excess is dangerous.

Glucose is essential for all organs and tissues of the body. The metabolism of glucose generally works as follows. As a result of the breakdown of carbohydrates consumed with food, simple monosaccharides (glucose) are formed in the digestive system, which enters the bloodstream through the intestines. Blood carries glucose to tissues and organs, where it penetrates cells and oxidizes, breaking down into carbon dioxide and water, which then re-enter the blood and are removed with exhaled air or urine.

If there is more glucose in the blood than the body needs, the liver converts it into glycogen, which accumulates in liver cells and muscles. If there is insufficient glucose, the reverse process occurs – the body extracts it from glycogen, and if that is not enough, from fat stores and even muscle tissue. The rate of metabolism varies among individuals, and carbohydrates enter the body unevenly, so normal blood glucose levels can fluctuate within a fairly wide range.

Next, let’s look at how exactly glucose enters tissues, why the body needs insulin, and how it works.

Some tissues and organs—such as brain cells, nerve fibers, retinal cells, kidneys, and adrenal glands—are capable of absorbing glucose directly from the blood. However, many organs require a mediator to facilitate the transfer of glucose into cells. This mediator is insulin, a hormone produced by the beta cells of the pancreas. It’s important to note that insulin, like other hormones, has multiple functions in the body, and not all of them are well understood. However, its role in carbohydrate metabolism is well established.

Diabetic syndrome develops in two cases: when insulin is either not produced or is produced in insufficient amounts, or when for some reason the cells of organs and tissues do not respond to insulin, a condition known as insulin resistance (IR).

The cessation of insulin production is characteristic of Type 1 Diabetes (T1D). Insulin resistance is a sign of Type 2 Diabetes (T2D).

Types of Diabetes

Type 1 Diabetes vs. Type 2 Diabetes

Diabetes mellitus is a group of endocrine disorders characterized by chronic hyperglycemia (elevated blood glucose levels). According to current classification, this group includes:

• Type 1 Diabetes (T1D)
• Type 2 Diabetes (T2D)
• Specific types of diabetes (associated with hereditary and acquired damage to the pancreas)
• Gestational diabetes (diabetes during pregnancy)

Type 1 Diabetes—formerly known as juvenile or insulin-dependent diabetes—is caused by the complete or partial cessation of insulin production by the pancreas. This type usually appears during adolescence (hence “juvenile”) and requires lifelong regular insulin administration from the onset of the disease. It is predominantly genetic and occurs in less than 10% of cases.

Specific forms of diabetes are also quite rare and are typically either genetic or caused by toxic damage to the pancreas.

Type 2 Diabetes is the most common form of diabetes, accounting for around 90% of cases and is considered the most significant problem in terms of prevention and treatment. T2D typically develops in adults (over 45 years old), but increasingly, cases are being reported in younger individuals (ages 25-30). The onset of the disease is often hidden, asymptomatic, and frequently unnoticed by patients and doctors.

Type 2 Diabetes is referred to as insulin-independent diabetes because, in the early stages of the disease, the pancreas does not reduce insulin production and often increases it. However, the body’s tissues partially or fully stop responding to insulin, leading to insulin resistance. This disrupts carbohydrate metabolism, increasing glucose absorption, which creates an excess of glucose in the blood that can be destructive to many organs and tissues. Over time, beta-cell dysfunction occurs—these are the cells in the pancreas responsible for insulin production. Consequently, insulin production decreases, leading to the second stage of T2D—relative insulin deficiency.

Symptoms of Uncontrolled Type 2 Diabetes (Progression and Worsening):

• Persistent, unexplained weakness and drowsiness
• Blurred vision
• Thirst and dry mouth
• Frequent urination
• Reduced appetite during decompensation, while in a compensated state, frequent hunger
• Itchy skin (often in the genital area in women)
• Slow-healing wounds
• Numbness in extremities

Prediabetes or Impaired Glucose Tolerance

While Type 1 Diabetes (T1D) typically develops rapidly and is relatively straightforward to diagnose, Type 2 Diabetes (T2D) often has a long latent period where metabolic disturbances are present but symptoms are either not fully apparent or are not given much attention by patients. Blood glucose levels in this stage are higher than normal but not yet in the diabetic range. This condition is known as prediabetes.

Symptoms of prediabetes are nonspecific and may include excess body weight, drowsiness, weakness, fatigue, headaches, and decreased immunity. These symptoms are often attributed to overwork, lack of sleep, or stress, but they may signal the beginning of the disease.

Forms of Prediabetes:

1. Impaired Glucose Tolerance (IGT):

• Morning blood sugar levels may be normal, but glucose levels rise rapidly after eating and return to normal slowly. The regulatory systems responsible for glucose metabolism are not functioning optimally. Blood glucose levels are higher than normal but below diabetic thresholds.

1. Impaired Fasting Glucose (IFG):

• Characterized by hypoglycemia, or a drop in blood glucose levels below normal after prolonged periods without food (e.g., in the morning). This indicates a problem with glucose storage or extraction processes in the body.

Both forms of prediabetes are precursors to diabetes but can be reversible with appropriate measures, making prediabetes a prompt for prevention rather than a definitive diagnosis. Without intervention, about 30% of individuals with IGT will develop diabetes within 5 years.

Prediabetes also increases the risk of cardiovascular diseases, causes angiopathies, damages nerve cells, and leads to other complications.

Diagnosis of Prediabetes: Glucose Tolerance Test

Traditionally, prediabetes is diagnosed using an oral glucose tolerance test (OGTT). This involves:

1. Fasting blood sample collection in the morning after a period without food.
2. Administering either an intravenous glucose solution or having the patient drink a glucose solution containing 75 grams of glucose.
3. Taking a subsequent blood sample two hours after glucose administration.

The results of this test can be influenced by various factors, such as recent food or drink intake, medications, overall health, and any exacerbation of illnesses. Patients should follow their doctor’s instructions carefully to ensure accurate results, and the test may need to be repeated on different days to account for random factors.

It is important to note that the standard glucose tolerance test is no longer considered a reliable diagnostic method. Since 2011, the recommended diagnostic marker is the Hemoglobin A1c (HbA1c) test. HbA1c measures the average blood glucose level over the past three months by assessing the glucose bound to hemoglobin in red blood cells.

Measurement	Normal	Prediabetes	Diabetes
Glycated Hemoglobin (HbA1c)	Up to 5.6%	5.7% to 6.4%	6.5% or higher
Fasting Blood Glucose	3.5 to 5.5 mmol/L	5.6 to 6.9 mmol/L	7 mmol/L or higher
Oral Glucose Tolerance Test (OGTT) (2 hours after glucose intake)	Up to 7.8 mmol/L	7.8 to 11.1 mmol/L	Above 11.1 mmol/L