Did you know: Diabetes mellitus

Type 1 diabetes is an autoimmune disease in which the immune system mistakenly attacks the body’s own cells. The condition is often diagnosed in childhood or adolescence, but can occur at any age. In type 1 diabetes, the insulin-producing beta cells in the pancreas are destroyed by misdirected immune responses within the body. Symptoms often only become apparent at an advanced stage, when insufficient insulin is being produced. The implications of this for treatment are explained in the “Treatment” section.

The exact causes of type 1 diabetes are not yet fully understood. However, it is known that both genetic factors and environmental influences play a role. Unlike type 2 diabetes, type 1 diabetes is not caused by an unhealthy diet or a lack of exercise.

Type 2 diabetes is the most common form of diabetes and accounts for around 90 % of all cases of diabetes worldwide. The number of people with diabetes has risen significantly worldwide in recent decades and is expected to continue to go up. The condition used to be commonly referred to as adult-onset diabetes. Today, however, younger adults, and in some cases even adolescents, are increasingly being diagnosed with it. A key contributing factor is the increasing prevalence of overweight and a lack of physical activity from a young age.

The development of type 2 diabetes is influenced by various factors. The main risk factors include a genetic predisposition, a lack of physical activity and being overweight, particularly an increased accumulation of fat in the abdominal area (central obesity). Advanced age, smoking, high blood pressure and lipid metabolism disorders also increase the risk. When abdominal obesity occurs alongside at least two other risk factors, such as high blood pressure, elevated blood sugar levels or lipid metabolism disorders, this is referred to as metabolic syndrome. This increases the risk of both type 2 diabetes and cardiovascular disease.

People with a parent who has type 2 diabetes have a significantly increased risk of developing it. However, it is not the condition itself that is inherited, but a genetic predisposition. Whether this actually leads to the development of type 2 diabetes also depends on lifestyle. As family members often share similar lifestyle habits, the family environment can also contribute to the development of the condition, alongside genetic predisposition.

Unlike type 1 diabetes, the problem with type 2 diabetes is usually not initially a lack of insulin, but rather what is known as insulin resistance. This means that the body’s cells no longer respond adequately to the hormone insulin. As the condition progresses, insulin production by the pancreas may also decline, leading to a lack thereof.

Type 2 diabetes usually develops gradually over many years and it is often preceded by a state known as prediabetes, in which blood sugar levels are already elevated, although the criteria for diabetes have not yet been met.

Unlike with type 1 diabetes, a healthy diet, regular exercise and maintaining a healthy weight can significantly reduce the risk of developing type 2 diabetes.

The symptoms of diabetes can vary in severity depending on its type. Whilst type 2 diabetes often develops gradually over many years and may go unnoticed for a long time, the symptoms of type 1 diabetes often develop within a short period.

Typical symptoms include increased thirst (polydipsia), frequent urination (polyuria), tiredness and exhaustion. Vision problems, night-time calf cramps, itching, frequent skin or urinary tract infections, and impaired wound healing may also occur.

In type 1 diabetes, unintentional weight loss is also a common occurrence. If the condition remains untreated, it can lead to a severe metabolic imbalance (diabetic ketoacidosis), which requires immediate medical attention.

As the symptoms are often non-specific, diabetes is not always diagnosed at an early stage.

If diabetes remains untreated for a prolonged period, or if blood sugar levels are persistently high, this can cause damage to blood vessels and nerves. The heart, brain, eyes, kidneys and feet are particularly affected.

Damage to blood vessels and nerves

Elevated blood sugar levels damage both small and large blood vessels. This can accelerate the development of atherosclerosis (hardening of the arteries), a condition in which the blood vessels narrow and harden. As a result, organs and tissues receive a reduced supply of oxygen and nutrients. At the same time, nerves can also be damaged. Many complications of diabetes arise from the combined effects of vascular and nerve damage.

Cardiovascular diseases

People with diabetes are at increased risk of cardiovascular diseases such as heart attack, stroke or peripheral arterial disease (PAD), a condition affecting blood flow to the legs. Worldwide, cardiovascular diseases are among the leading causes of death in people with diabetes. Risk factors such as high blood pressure, elevated blood lipid levels or smoking can further increase this risk.

Furthermore, people with type 2 diabetes have an increased risk of certain types of cancer. In Germany and some other countries, however, cancer has become significantly more prevalent in recent years and is now also among the leading causes of death. One factor contributing to this is that people with diabetes are now receiving better treatment and are more likely to live to an older age.

Eyes

The eyes can also be damaged by persistently high blood sugar levels. A common consequence is diabetic retinopathy, a condition affecting the retina. If left untreated, it can lead to a significant deterioration in vision, or even blindness. Regular check-ups with an ophthalmologist help to detect and treat changes at an early stage.

Kidneys

Over time, diabetic kidney disease (diabetic nephropathy) may also develop. Around 30–40 % of people with diabetes are affected by this as the condition progresses. Since the kidneys filter the blood, they are particularly sensitive to persistently high blood sugar levels. Diabetic nephropathy often develops unnoticed and should therefore be detected early through regular check-ups. In advanced cases, dialysis (blood filtration) may become necessary.

Nerves and feet

In addition, nerves can be damaged (diabetic neuropathy). Around one in two people with diabetes develop signs of diabetic neuropathy as the condition progresses. This can manifest, for example, as tingling, numbness or pain. The feet are particularly commonly affected, although in principle various nerves throughout the body can be damaged.

Due to the combination of diabetic neuropathy and circulatory problems, injuries to the feet can often go unnoticed and heal more poorly. This increases the risk of chronic wounds and infections. This condition is known as diabetic foot syndrome and, in severe cases, may require surgical treatment or even amputation.

Other effects of diabetes

Diabetes can also affect sexual function. Men are more likely to suffer from erectile dysfunction, whilst women may experience, amongst other things, sexual dysfunction and discomfort during sexual intercourse. These are often caused by circulatory and nerve damage.

Last but not least, diabetes can also affect mental health. The condition and its treatment represent a constant burden for many people affected. People with diabetes are therefore more likely to suffer from stress, anxiety or depression than the general population.

Diabetes is diagnosed by measuring the blood sugar level and evaluating them on the basis of established threshold values.

Between normal blood sugar levels and diabetes lies a condition known as prediabetes. In this condition, blood sugar levels are already elevated but do not yet reach the thresholds required for a diagnosis of diabetes. At this stage in particular, lifestyle changes can help to delay or even prevent the onset of type 2 diabetes.

Since diabetes often causes no symptoms for a long time, it frequently goes unnoticed at first. It is not uncommon for it to be detected only during routine or screening examinations. Screening examinations therefore play an important role, particularly for people with risk factors such as being overweight, a lack of physical activity, high blood pressure or a family history of diabetes.

In healthy people, fasting blood glucose should be below 100 mg/dl or below 5.6 mmol/l. A diagnosis of diabetes is made when levels reach 126 mg/dl or 7.0 mmol/l. In between lies a grey area where levels are already elevated and indicate prediabetes.

In addition to blood glucose, the HbA1c level (long-term blood glucose) also plays an important role in the diagnosis.

It describes the proportion of the red blood pigment (haemoglobin) in the blood to which glucose has attached itself. As this level changes more slowly than blood glucose, it is suitable for assessing average blood glucose levels over the past 8–12 weeks. The HbA1c level is therefore also referred to as the “blood glucose memory”. In people without diabetes, it is usually below 5.7 %. A level of 6.5 % or higher indicates diabetes.

In certain cases, an oral glucose tolerance test (oGTT) may also be carried out. This test examines how blood glucose levels change after drinking a sugary solution and it is also used to diagnose prediabetes or gestational diabetes.

Following a diabetes diagnosis, regular check-ups are important for monitoring blood glucose control and detecting any potential complications at an early stage.

The HbA1c level is measured regularly to assess long-term blood glucose control. It serves as an important parameter for monitoring progress and helps to evaluate the success of treatment.

People with type 1 diabetes, in particular, must also monitor their blood glucose levels regularly on their own in order to adjust their insulin dose and to detect and prevent blood glucose fluctuations at an early stage. In addition to the traditional method of measuring blood glucose by pricking the fingertip, continuous glucose monitoring (CGM) systems are now available, which continuously measure glucose levels in the tissue.

Regular check-ups also play a particularly important role. They help to identify potential complications at an early stage and treat them in good time. These include, amongst other things, monitoring weight, blood pressure and blood lipid levels, as well as regular examinations of the eyes, kidneys, nerves, feet and the cardiovascular system.

The treatment of diabetes depends on various factors, in particular its type, its severity and any associated conditions.

Regardless of the type of diabetes, healthy lifestyle habits form the basis of any diabetes treatment. A balanced diet, regular physical activity, a healthy body weight and not smoking can help to improve blood sugar levels and reduce the risk of complications. Education and support programs are also an important part of treatment. They provide information about the disease and help people with diabetes better understand their condition and manage it independently in their daily lives. In Germany, structured diabetes education programs are often offered for this purpose.

Treatment also includes regular check-ups, good foot care and – depending on the type of diabetes – medication. Comorbidities such as high blood pressure or lipid disorders should also be treated consistently, as they can further increase the risk of cardiovascular disease.

As people with type 1 diabetes can no longer produce sufficient insulin themselves to meet their metabolic needs, they must administer it through external means for the rest of their lives. This is done using insulin injections or an insulin pump. The amount required depends on many factors, such as the composition and quantity of food, physical activity, stress or other medical conditions. Comprehensive education on insulin therapy, nutrition, and exercise is therefore particularly important. As well as high blood sugar levels, people with type 1 diabetes must also be mindful of hypoglycaemia.

In type 2 diabetes, lifestyle changes form a particularly important part of treatment. A balanced diet, regular exercise and weight loss if overweight can significantly improve blood sugar levels and slow the progression of the condition. Particularly in the early stages, this can help to delay or reduce the need for medication. If lifestyle changes alone are not sufficient, blood sugar-lowering medication is used. In type 2 diabetes, there is usually no insulin deficiency to begin with. Instead, the body’s cells become increasingly less responsive to the insulin that is present (insulin resistance). Many medicines therefore aim to lower blood glucose levels or improve the action of the body’s own insulin.
Various classes of active substances are now available for this purpose. The choice of medicine depends, amongst other things, on blood glucose levels, comorbidities and individual treatment goals. Metformin is often used as a first-line treatment. In addition, other medicines are available, such as SGLT2 inhibitors, GLP-1 receptor agonists, DPP-4 inhibitors or sulphonylureas. Some of these medicines can not only lower blood sugar levels but also reduce the risk of cardiovascular disease or kidney damage.
As the condition progresses, treatment with insulin may also become necessary for people with type 2 diabetes if the body’s own insulin production is no longer sufficient or if other treatments do not achieve the desired results.

Which medication or combination of medications is best should be discussed individually with your doctor.