Type 2 diabetes: causes, treatment, prevention

Type 2 diabetes: causes, treatment, prevention

Diabetes type 2: short overview

  • Causes: Insulin resistance (insensitivity of body cells to insulin); various risk factors are involved in the development of the disease, including genetic predisposition, overweight, lack of exercise, metabolic syndrome
  • Age of onset of the disease: usually after the age of 40, but increasingly overweight children and adolescents also suffer from type 2 diabetes
  • Symptoms: develop gradually, for example fatigue, increased susceptibility to infections, dry skin, itching and increased thirst. At diagnosis, sometimes symptoms of secondary diseases are already present, such as impaired vision or circulatory problems in the legs.
  • Important research: Measurement of blood sugar and HbA1c, oral glucose tolerance test (oGTT), examinations of concomitant and secondary diseases (high blood pressure, diabetic retinopathy, diabetic foot, etc.)
  • Treatment options: Change of diet, lots of exercise, blood sugar-lowering tablets (oral antidiabetics), insulin (in advanced stages)

Diabetes type 2: Description

Diabetes mellitus type 2 is a widespread disease affecting more than eight million people in Germany. In recent decades, the number of patients has increased significantly, also in other industrialized countries. Previously, diabetes type 2 was primarily a disease of older people. This is why it was often referred to as “adult-onset diabetes”.

In the meantime, important risk factors of the disease (such as severe overweight, lack of exercise) often exist even at a younger age. As a result, young adults and even children are increasingly suffering from type 2 diabetes, and the term “adult-onset diabetes” has lost its validity.

Diabetes type 2 a/b (diabetes without or with overweight)

Some doctors make a fine adjustment for type 2 diabetes – depending on whether or not there is also pathological overweight (obesity). This is the case with most patients. They are assigned to the subgroup diabetes mellitus type 2b. Only a small proportion of patients are not obese: this is the group of diabetes type 2a.

Diabetes type 2: Symptoms

Many people with type 2 diabetes are obese (obese) and older. Diabetes itself often does not cause any symptoms for a long time (asymptomatic course). Sometimes it also causes unspecific symptoms such as tiredness, lack of concentration, itching or dry skin. In addition, the pathologically elevated blood sugar level makes patients more susceptible to infections, for example of the skin and mucous membrane (such as fungal infections) or the urinary tract.

If diabetes type 2 has already led to secondary diseases, corresponding symptoms can also occur. These can be, for example, impaired vision or even blindness in cases of diabetes-related retinal damage (diabetic retinopathy). If the constantly elevated blood sugar levels have damaged the vessels and nerves, poorly healing ulcers and wounds can develop on the foot or lower leg (diabetic foot).

Read more about the signs and symptoms of type 2 diabetes in the article diabetes-symptoms-and-follow-up.

Type 2 diabetes: causes and risk factors

Insulin plays an important role in type 2 diabetes. This hormone is produced by the beta cells of the pancreas and is released into the blood when needed. It ensures that the sugar (glucose) circulating in the blood reaches the body cells that need it to produce energy.

In type 2 diabetes, the pancreas usually produces sufficient amounts of insulin at the beginning. However, the body cells (for example in the liver or muscles) are becoming increasingly insensitive to this. The number of binding sites for insulin on the cell surfaces decreases. Due to this growing insulin resistance, the amount of insulin available is no longer sufficient to transport the blood sugar into the cells. There is a relative insulin deficiency.

The body tries to compensate for this by increasing insulin production in the pancreatic beta cells. In late stages of the disease, this constant overload can exhaust the pancreas to such an extent that insulin production decreases. Then an absolute insulin deficiency can develop, which can only be compensated by insulin injections.

Experts now know of various risk factors that promote the disease mechanism described here and can thus contribute to the development of type 2 diabetes. A distinction is made between risk factors that can and cannot be influenced. Today, it is assumed that diabetes mellitus type 2 is caused by a combination of several factors and not by one factor alone.

Risk factors that can be influenced

Those affected themselves have a great influence on risk factors that can be influenced. If these factors are minimized, type 2 diabetes can be prevented. Even people who are already diabetic should eliminate these risk factors if possible. This often helps to prevent complications and secondary diseases.

Overweight: The majority of diabetics (type 2) are overweight or even obese. Even if obesity is not the sole cause of the disease, it may be the decisive trigger: fat cells (adipocytes) release various messenger substances (hormones, inflammatory substances) into the blood, reducing the insulin sensitivity of the cells over time. The fat cells of the abdominal fat in particular seem to be dangerous, as they produce a particularly large number of such messenger substances. An increased abdominal girth (men: > 94 centimetres; women: > 80 centimetres) is therefore considered to be particularly harmful to the sugar metabolism.

Lack of exercise: Lack of exercise has a negative effect on the energy balance: People who move burn energy absorbed with food. Without this exercise, a surplus of calories is produced with a constant food intake. This is reflected in an increased blood sugar level and the build-up of fatty tissue.

Metabolic syndrome: The metabolic syndrome is a combination of abdominal obesity (abdominal adiposity), elevated blood lipid levels (dyslipoproteinemia), high blood pressure (hypertension) and a disorder of sugar metabolism (insulin resistance). It is considered an important risk factor for type 2 diabetes and other diseases such as heart attack and stroke.

Other risk factors for type 2 diabetes are

  • Smoking
  • a diet low in fibre, rich in fat and sugar
  • certain drugs that impair sugar metabolism, such as the contraceptive pill, antidepressants, diuretics and blood pressure reducers

Risk factors that cannot be influenced

The following risk factors cannot be influenced by those affected. Nevertheless, one should know them: Type 2 diabetes can remain undetected for a long time. People with the risk factors mentioned here should therefore pay particular attention to their blood sugar:

Heredity: The genetic predisposition seems to play an important role in type 2 diabetes. For example, identical (congenital) twins almost always both suffer from type 2 diabetes, not just one alone. Daughters of sick mothers have an approximately 50% risk of developing type 2 diabetes. If both parents are ill, the risk for children increases to 80 percent. Researchers now know of more than 100 genes that apparently can increase the risk of type 2 diabetes.

Age: The risk of diabetes type 2 increases with age, as the effect of insulin may diminish over time, just as it does for overweight people. To compensate, the pancreas releases more insulin into the bloodstream, which in turn reduces its effectiveness on the cell surface.

Hormonal diseases:Endocrinological diseases can also increase the risk of type 2 diabetes. This applies, for example, to polycystic ovarian syndrome (PCO).

Diabetes type 2: examinations and diagnosis

If diabetes type 2 is suspected, the right contact person is your family doctor or a specialist in internal medicine and endocrinology or diabetology.

The doctor first takes your medical history (anamnesis) by talking to you in detail. He will have your complaints and any previous illnesses described in detail. Possible questions your doctor may ask during this conversation include

  • Do you have to urinate frequently in large quantities lately?
  • Do you suffer from constant thirst even though you drink large quantities?
  • Do you often feel weak and tired?
  • Does anyone in your family suffer from type 2 diabetes?

This is followed by a physical examination. Here the doctor pays particular attention to whether you can feel fine touches on your hands and feet. A loss of sensitivity could already indicate diabetes-related nerve damage (diabetic polyneuropathy). In addition, the doctor will check whether any wounds have already developed on the foot due to the sensory disorder (diabetic foot). Basically, an examination of the fundus of the eye is also one of the typical diabetes examinations. However, this is usually carried out by the ophthalmologist.

Diabetes test

Very important for the diagnosis of diabetes is the analysis of a blood sample taken when fasting. The fasting blood glucose is measured in this sample. The so-called HbA1c value in the blood is also determined. It shows how high the average blood sugar level was in the last two to three months.

The sugar content of a urine sample is also determined: If the blood sugar level is very high, the body tries to get rid of the excess via the kidneys.

In order to be able to assess the efficiency of the sugar metabolism more precisely, the doctor can subject you to an oral glucose tolerance test (oGTT).

You can read more about the necessary examinations and tests for the diagnosis of diabetes mellitus in the article Diabetes Test.

Type 2 diabetes: treatment

The aim of diabetes type 2 treatment is to permanently lower elevated blood sugar levels to a healthier level. This is the only way to prevent severe secondary diseases of type 2 diabetes.

To monitor the success of the therapy, the HbA1c value is determined at regular intervals. For non-diabetics it is generally less than 6.0 percent. In type 2 diabetes patients, it often rises much higher if untreated. They are usually advised to aim for an HbA1c target value of 6.5 to 7.5 percent in the course of therapy. For older people who do not yet have diabetes-typical symptoms, a higher target value may also be acceptable.

In general, the following applies: How much the blood sugar level should be lowered in an individual case depends on the age and general health of the patient as well as on any concomitant diseases (high blood pressure, lipid metabolism disorders, overweight, etc.).

Successful diabetes type 2 treatment also includes the therapy of such concomitant diseases. In this way the course of the disease can be positively influenced.

Diabetes type 2 treatment: Stage scheme

The basis of diabetes type 2 therapy is a lifestyle change with a change of diet, more exercise, reduction of overweight and a stop smoking. Patients should also participate in diabetes education.

For some patients, a better understanding of their own illness and lifestyle changes is sufficient to reduce the elevated blood sugar level. If this does not succeed, the doctor prescribes additional medication: Blood sugar reducer to take (oral antidiabetics) and/or insulin.

Overall, diabetes type 2 treatment follows a step-by-step scheme. Each level is applied for three to six months. If the individual HbA1c target value could not be reached during this time, the patient is switched to the next stage of diabetes type 2 treatment:


Step 1 Diabetes education and lifestyle change (weight reduction, exercise, dietary change, smoking cessation)
Step 2 Monotherapy with an oral antidiabetic (usually metformin)
Level 3 Combination of two oral antidiabetics or insulin
Level 4 Insulin therapy possibly in combination with oral antidiabetic


Diabetes type 2 has become an epidemic in industrialized countries. The treacherous thing about it is that the disease develops very slowly and often goes unnoticed for years. Early detection is therefore very important. Because with the right measures, such as weight control or medication to regulate blood sugar levels, the serious and sometimes even fatal complications can be reduced.

The stress load has an indirect effect, especially on people who are permanently under electric current. This is because chronic stress leads to a permanently increased level of stress hormones in the body. And these have a very unfavorable effect on fat and carbohydrate metabolism, which can promote the development of type 2 diabetes.

Diabetes type 2 is actually a cardiovascular disease that affects the heart and vessels and is associated with an increase in blood sugar. Large studies have shown: Cardiovascular problems such as high blood pressure, heart attack or stroke occur in the early stages of type 2 diabetes. And until the diagnosis is finally made, the incidence of the disease even increases.

Diabetes Education

As the very first therapeutic measure, before medication is used, lifestyle adjustments should always be made. Participation in a diabetes type 2 training course can help here. There, affected persons learn more about the development of type 2 diabetes, the possible symptoms and secondary diseases as well as the treatment options. Among other things, you will receive helpful tips on nutrition, weight loss and physical activity. Talk to your attending physician about possibilities of attending such training.

More movement

Physical exercise is one of the most important therapeutic components in type 2 diabetes, as it can improve the action of insulin and thus lower blood sugar levels. Physical activity also prevents dangerous consequences of diabetes type 2 (such as cardiovascular disease), increases fitness and improves the quality of life of patients.

To this end, patients should, on the one hand, provide more exercise in everyday life. This can be done by going for a walk regularly or by taking the stairs instead of the lift.

On the other hand, people with type 2 diabetes should exercise if possible. First of all, however, diabetes type 2 patients should definitely have a medical examination: In fact, the training programme must be adapted to the age, physical fitness and general state of health of the patient. The doctor (or a sports therapist) will help you choose a suitable sport and draw up an individually suitable training plan. Endurance training (such as cycling, swimming, Nordic walking etc.) and/or strength training are recommended.

The following applies: taking regular doses of exercise several times a week is much more useful and healthy than working yourself to exhaustion once a week. It also prevents such dangerous incidents as sudden severe hypoglycaemia.

By the way: Training together with friends, in a sports group or in a sports club can be helpful for your own motivation!

Adaptation of the diet

The correct diet for type 2 diabetes improves blood sugar levels, promotes weight loss where necessary and prevents the development of secondary diseases. The nutritional recommendations are thus adapted to the individual therapy goal and risk profile of a patient. They should also take personal likes and dislikes into account, otherwise it will be difficult to change their diet.

Experts disagree on how high the proportion of the individual main nutrients (carbohydrates, fats, proteins) in the diet should ideally be in type 2 diabetes. However, studies indicate that it is not so much the exact percentage of the main nutrients that matters, but rather their type and source.

For example, in the case of carbohydrates, preference should be given to products that contain a lot of soluble fibre or have little effect on the blood sugar level. These include whole grain products, pulses, potatoes, vegetables and fruit. Household sugar, honey, sweets and sugared drinks (such as cola, lemonade) should be consumed in small quantities at most by type 2 diabetes patients – especially if they are overweight.

With dietary fats, attention should be paid to a high proportion of mono- or polyunsaturated fatty acids. It is found especially in vegetable fats such as olives and rapeseed oil. Animal fats (meat, sausage, cream, butter etc.) should be consumed sparingly. Especially overweight people with type 2 diabetes should prefer low-fat products such as low-fat cheeses.

Proteins should not account for more than 10 to 20 percent of the total amount of energy supplied during the day. This recommendation applies to people with type 2 diabetes, provided they do not show signs of kidney damage (nephropathy). With existing kidney weakness, diabetics should consume a maximum of 0.8 grams of protein per kilogram of body weight. Important sources of protein include fish, meat and dairy products.

Numerous “diabetic products” and “diet products” for diabetics are available in the trade. Experts advise against eating these industrially produced foods. Many products contain no sugar, but more fat and calories than normal products.

In addition, dietary products often contain a lot of fructose (fructose). However, in larger quantities it has a harmful effect on health: It promotes obesity (adiposity), favours the metabolic syndrome, increases blood fat values and uric acid levels. Diabetics should therefore avoid products with a lot of fruit sugar. In addition, normal household sugar should not – as is often recommended – be replaced by fruit sugar (for example when baking cakes).

Alcohol should be consumed in moderate amounts at most in diabetes type 2. This means: No more than one or two small glasses per day. Many experts recommend the simultaneous intake of carbohydrate-rich foods: The carbohydrates raise the blood sugar level, the alcohol lowers it. For example, a bottle of beer a day can balance the effect on blood sugar.

Stop smoking

Diabetes type 2 promotes the development of cardiovascular diseases such as stroke and heart attack. This risk is further aggravated if diabetics also smoke. Therefore, cigarettes & Co. should be avoided if possible. A doctor can advise smokers on ways to quit smoking (nicotine patches etc.) and provide valuable assistance.

Oral antidiabetics

If lifestyle changes do not bring type 2 diabetes under control, additional oral antidiabetics are used. As a rule, the treatment is started with a single active substance (monotherapy, usually with metformin). If this is not enough, the doctor prescribes either two oral antidiabetics or insulin.

The following active ingredients are available:


Drug class Examples Effect Possible side effects
Biguanide Metformin Increases the effect of insulin. Lowers blood lipids and cholesterol. Curbs appetite and therefore contributes to weight reduction. Rare but dangerous side effect: Lactic acidosis (acidification of the blood)
Sulfonylureas Glibenclamide, gliquidone, glimepiride etc. Increases the release of insulin from the pancreas. Weight gain. Risk of hypoglycaemia.
Glinides (“sulfonylurea analogues”) Repaglinide, nateglinide Increases the release of insulin from the pancreas. Weight gain. Risk of hypoglycaemia.
Glitazones ( insulin sensitizationhe”) Pioglitazone Cells become more sensitive to insulin Weight gain
Alpha glucosidase inhibitors Acarbose Inhibit sugar-cleaving enzymes in the intestinal mucosa. In this way, sugar is not absorbed, but excreted undigested. Often poor tolerance
Gliptin (DPP-IV inhibitor) Sitagliptin, vildagliptin etc. Increases the release of insulin from the pancreas. Low weight gain
SGLT2 inhibitors (Gliflozine) Dapagliflozine Increased excretion of glucose in the urine Urinary tract infections


Metformin and sulfonylureas have been in use longest in type 2 diabetes. The others are newer antidiabetics.

For some time now there have also been so-called incretin mimetics (such as Exenatide). They are not taken as tablets but injected under the skin. In studies, they were able to lower blood sugar levels and reduce HbA1c levels. Incretin mimetics may be considered if the combination of different oral antidiabetics is not sufficiently effective.

Insulin therapy

There are many different insulin types. They differ mainly in how quickly and how long they act after eating (injection-meal distance and duration of action). Insulin can also be used in a variety of ways.

For example, some people with type 2 diabetes are treated with both an oral antidiabetic and insulin. For example, they take metformin and inject themselves with so-called normal insulin before a meal, into the subcutaneous fat tissue (subcutaneously) around the stomach.

Other patients are treated exclusively with insulin, whereby there are different therapy schemes:

Conventional insulin therapy: Conventional (conventional) insulin therapy is particularly useful for diabetes type 2 patients who have a fixed daily routine and diet (e.g. in nursing homes). As a rule, a so-called mixed insulin is injected twice a day (before breakfast and dinner). It consists of a short-acting and a long-acting insulin analogue, i.e. it acts both quickly and for a long time. The blood sugar is determined beforehand.

This relatively rigid scheme does not allow for significant variations in the dietary plan and the level of physical activity. For example, if a meal is forgotten or omitted, there is a risk of hypoglycaemia. In addition, conventional insulin therapy has a tendency to cause weight gain.

Intensified insulin therapy (basic bolus principle): The so-called intensified insulin therapy requires more effort from the patient, but at the same time offers more freedom. In addition, it can more effectively prevent the consequences of diabetes by lowering blood sugar levels more effectively.

According to the so-called basic bolus principle, a long-acting insulin is usually injected once or twice a day. It covers the basic insulin requirement for one day (basic insulin or basal insulin). In addition, normal insulin or a short-acting insulin is injected before a meal (bolus). The current blood sugar value is measured first. The dose of bolus insulin depends on its level and the carbohydrate content of the planned meal.

This form of therapy for type 2 diabetes requires particularly good patient training and cooperation (compliance). In return, they are allowed to eat what and when they want, and can engage in sports if they are sufficiently adapted. However, extreme physical exertion can derail the sugar metabolism due to an increased release of adrenaline.

An insulin pump, which is often used for type 1 diabetes, is only used in individual cases of type 2 diabetes.

Diabetes type 2: course of disease and prognosis

Whether type 2 diabetes is curable depends strongly on the patient’s cooperation and willingness to change his or her lifestyle (healthier diet, more exercise, etc.). However, such general measures and diabetes medication (if necessary) definitely help to slow down the progression of the disease and prevent possible complications: the better it is possible to lower the blood sugar level, the lower the risk of secondary diseases such as heart attack, stroke or kidney weakness. The extent of the secondary diseases has a decisive influence on the prognosis of diabetes type 2!

Prevent type 2 diabetes

The best way to prevent type 2 diabetes is to have a healthy body weight, a balanced, varied diet and regular, adequate exercise. Especially people who already have impaired glucose tolerance (but not yet diabetes) should implement these measures. They should also go for regular check-ups with their family doctor. In this way, type 2 diabetes can be detected and treated at an early stage.


Sandra Eades

Hello I am Sandra Eades, physician, researcher and author from Australia. I am working currently as researcher for a private institution. I have studied in Britain and Australia, where I currently reside. I write about research topics in the organization of the public health government agencies. For the iMS I write about general medical conditions. I also research scholar sources to provide information to writers of other articles. I also check the citations of scholar papers. Finally, I read other articles before they are published. I am also a mother of three children!

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