Diabetes

What Is Diabetes?

Diabetes is a group of metabolic diseases that cause blood glucose (blood sugar) levels to remain high over a prolonged period. Insulin is secreted by the pancreas and helps the body use glucose. Diabetes can develop when the body does not produce enough insulin, cannot use insulin effectively, or both mechanisms are affected.

Diabetes can occur at any age. Type 1 diabetes does not occur only in children, nor does type 2 diabetes occur only in adults. The type of diabetes and its treatment are determined by a physician based on an assessment of the person's clinical findings and the necessary investigations.

How Is Diabetes Diagnosed?

A diagnosis of diabetes is based on blood glucose or HbA1c results measured using appropriate laboratory methods. According to the ADA 2026 criteria, any of the following results is within the diabetes range in non-pregnant individuals:

1. Fasting plasma glucose 126 mg/dL or higher
2. Plasma glucose at two hours during a 75 g OGTT 200 mg/dL or higher
3. HbA1c 6,5% or higher
4. Random plasma glucose 200 mg/dL or higher in the presence of diabetes symptoms or a hyperglycaemic crisis

In the absence of clearly elevated blood glucose or a hyperglycaemic crisis, the diagnosis must be confirmed by repeating the same test or by obtaining abnormal results on two different tests. HbA1c testing must be performed using an appropriate, standardised laboratory method. 

The criteria used for prediabetes (elevated blood glucose in the prediabetic range) are HbA1c 5,7–6,4%, fasting glucose 100–125 mg/dL, or a glucose level of 140–199 mg/dL at two hours during a 75 g OGTT. These results do not constitute a diagnosis of diabetes; they indicate an increased risk of developing type 2 diabetes in the future. As different tests may identify different individuals, test selection and interpretation of results are guided by clinical assessment. Learn about our diabetes test package.

What Are the Types of Diabetes?

Type 1 Diabetes

In type 1 diabetes, the immune system damages the insulin-producing cells in the pancreas, and insulin production decreases significantly or stops. It can begin at any age. People with type 1 diabetes require insulin therapy to manage their blood glucose. 

Type 1 diabetes can sometimes develop rapidly. Excessive thirst, frequent urination, unexplained weight loss and fatigue may occur. Nausea, vomiting, abdominal pain, deep and rapid breathing, confusion or fruity-smelling breath may be signs of diabetic ketoacidosis. This condition requires urgent medical assessment. 

Type 2 Diabetes

In type 2 diabetes, the body may not use insulin effectively, and over time the pancreas may also become unable to produce enough insulin. Genetic predisposition, age, excess weight, physical inactivity and certain health conditions can affect the risk. However, type 2 diabetes does not occur only in people with obesity; people diagnosed with the condition may have no symptoms for a long time.

Gestational Diabetes

Gestational diabetes is elevated blood glucose detected during pregnancy. Hormonal and metabolic changes during pregnancy can increase insulin requirements. Screening is usually performed at 24–28 weeks of pregnancy. The method used and the diagnostic thresholds may vary depending on whether a one-step 75 g OGTT or a two-step protocol consisting of a 50 g screening test followed by a 100 g OGTT is used; the approach depends on the physician's decision and the relevant clinical protocol. 

People with gestational diabetes are advised to undergo reassessment with a 75 g OGTT 4–12 weeks after delivery. Regular follow-up for prediabetes or diabetes is required thereafter; the ADA recommends continued screening every 1–3 years. 

Other Types of Diabetes

More rarely, diabetes may develop due to single-gene disorders, pancreatic diseases or the effects of certain medications. The type of diabetes should therefore not be determined based on age or weight alone. 

What Are the Symptoms of Diabetes?

Diabetes may cause no symptoms for a long time in some people. Possible symptoms include:

1. Excessive thirst and frequent urination
2. Fatigue
3. Unexplained weight loss
4. Blurred vision
5. Slow wound healing or recurrent infections

If symptoms or risk factors for diabetes are present, medical assessment and appropriate blood tests should be sought.

What Are the Risk Factors for Diabetes?

The risk of type 2 diabetes may increase with factors such as family history, age, physical inactivity, excess weight, high blood pressure, abnormal blood lipid levels, polycystic ovary syndrome and a history of gestational diabetes. Type 1 diabetes has a different underlying mechanism; these risk factors do not apply directly in the same way as they do to type 2 diabetes.

Possible Complications of Diabetes

When blood glucose remains high over a prolonged period, the cardiovascular system, kidneys, eyes, nerves and feet may be affected. These problems do not necessarily develop in everyone with diabetes. Alongside blood glucose monitoring, regular assessment of blood pressure, blood lipids, kidney health and eye health helps reduce risks and detect problems early. 

How Is Diabetes Treated?

Treatment is planned according to the type of diabetes and the person's needs. Insulin therapy is essential in type 1 diabetes. In type 2 diabetes, nutrition, physical activity, education and medication are tailored to the individual; insulin may also be used when necessary. The treatment plan may be reassessed over time.

Diabetes cannot always be described as a condition that “has no cure and remains unchanged”. In some people with type 2 diabetes, particularly after significant weight loss, blood glucose levels may fall below the diabetes range without medication. This is called remission; follow-up continues because this does not mean that diabetes has permanently disappeared.

For people who need weight management, structured nutrition, physical activity and behavioural support may be part of treatment. Medications are also selected according to the person's clinical characteristics and goals. 

What Should a Diabetes Eating Plan Look Like?

The same diet or carbohydrate proportion is not suitable for everyone with diabetes. The ADA recommends individualising the eating plan according to the person's preferences, nutritional needs and health goals. An eating pattern that includes vegetables, whole fruits, legumes, whole grains, nuts and appropriate protein sources, while limiting sugary drinks, refined grains and highly processed products, may be considered. There is no need to eliminate carbohydrates completely or avoid all fruits. 

Fruit juice contains less fibre than whole fruit and, because it is consumed more quickly, may affect blood glucose. Therefore, in most cases, choosing whole fruit and limiting fruit juice is more appropriate. Water is the preferred drink. The eating plan and portion sizes can be determined with a doctor or dietitian, taking into account the person's medications and blood glucose readings. 

Diabetes in Children

Type 1 diabetes can occur in children; type 2 diabetes can also develop during childhood or adolescence. Excessive thirst, frequent urination, bedwetting that starts again, unexplained weight loss and fatigue are symptoms that require assessment. Urgent medical attention should be sought, particularly if there is vomiting, abdominal pain, deep and rapid breathing or an altered level of consciousness. 

Diabetes in children is diagnosed using appropriate blood glucose tests, as in adults; the results and symptoms are assessed together. Type 1 diabetes requires insulin treatment. Treatment for type 2 diabetes should be planned by a paediatric endocrinology team according to the child's age and clinical condition.