The condition affects people of different ages, including children, teenagers, adults and older people. Some forms develop quickly, while others may remain unnoticed for years because their early symptoms are mild. Understanding the warning signs, risk factors and available treatments can help people recognise when they need medical assessment.

According to the World Health Organization, the number of people living with diabetes increased from approximately 200 million in 1990 to 830 million in 2022. The growing burden has made prevention, early diagnosis and access to treatment important public-health priorities, particularly in low- and middle-income countries.

What Is Diabetes?

Diabetes mellitus is a condition characterised by persistently elevated blood glucose levels. Glucose comes from food and is also produced by the body. Under normal circumstances, insulin helps regulate how glucose is used and stored.

The pancreas produces insulin. When the body does not make enough of the hormone, or its cells do not respond to insulin properly, glucose regulation becomes impaired.

If blood sugar remains high for a long time, it can damage blood vessels and nerves. This may affect several organs, including the heart, kidneys and eyes. Diabetes can also increase the risk of stroke, foot ulcers and other serious complications.

The condition requires appropriate medical care, although its management differs according to the type of diabetes, the person's health and other individual circumstances.

The Main Types of Diabetes

There are three major types of diabetes: type 1, type 2 and gestational diabetes. Other, less common forms can develop because of genetic conditions, pancreatic diseases or certain medicines.

Type 1 Diabetes

Type 1 diabetes occurs when the body's immune system attacks and destroys the pancreatic cells responsible for producing insulin. As a result, the body produces little or no insulin.

The condition often begins during childhood or adolescence, although it can develop at any age. Its exact cause is not fully understood, but genetic susceptibility and environmental factors are believed to contribute.

Symptoms can develop over days or weeks and may become severe quickly. People with type 1 diabetes require insulin treatment to survive and need regular monitoring of their blood glucose levels.

Type 1 diabetes is not caused simply by eating too much sugar, and there is currently no established way to prevent it.

Type 2 Diabetes

Type 2 diabetes is the most common form of the condition. It develops when the body becomes resistant to insulin or cannot produce enough insulin to maintain normal blood glucose levels.

The condition is more common among adults, but it can also affect children and teenagers. Symptoms may develop gradually, sometimes over several years, meaning a person may have the condition without realising it.

Factors associated with type 2 diabetes include family history, increasing age, physical inactivity, excess body weight and certain metabolic or hormonal conditions. However, people can develop the condition without having every recognised risk factor.

Healthy lifestyle changes can help prevent or delay many cases of type 2 diabetes. People who already have the condition may also benefit from changes to eating habits and physical activity, alongside medication when needed.

Gestational Diabetes

Gestational diabetes is high blood glucose that develops or is first recognised during pregnancy in someone who did not previously have diabetes.

Pregnancy-related hormonal changes can make it harder for the body to use insulin effectively. Some people consequently develop blood glucose levels that are higher than normal.

Gestational diabetes may not cause noticeable symptoms, which is why healthcare professionals use screening tests during pregnancy.

If it is not appropriately managed, the condition can increase the risk of complications for both the pregnant person and the baby. After delivery, blood glucose levels may return to normal, but the parent has a higher risk of developing type 2 diabetes later.

Children born following a pregnancy affected by gestational diabetes may also have an increased risk of developing metabolic problems later in life.

Common Symptoms of Diabetes

The symptoms of diabetes vary depending on the type of condition and how high the blood glucose level has become.

Common warning signs include:

• Excessive thirst.
• Frequent urination, including during the night.
• Increased hunger.
• Unexplained weight loss.
• Persistent tiredness or weakness.
• Blurred vision.
• Tingling or numbness in the hands or feet.
• Wounds that heal slowly.
• Repeated infections.

Type 1 diabetes often produces symptoms that develop rapidly and can become severe within a short period. Type 2 diabetes usually progresses more gradually, and some people may have few noticeable symptoms during its early stages.

Gestational diabetes frequently has no obvious symptoms and is commonly identified through pregnancy screening.

These symptoms do not necessarily mean someone has diabetes because other medical conditions can cause similar problems. Blood tests and professional assessment are needed to establish the diagnosis.

What Causes Diabetes?

The causes differ according to the type of diabetes.

Type 1 diabetes is associated with an autoimmune process in which the immune system destroys insulin-producing cells in the pancreas. Researchers believe that genetic and environmental factors may influence the development of this process.

Type 2 diabetes results from a combination of insulin resistance and the body's inability to produce enough insulin to compensate. Genetics, age, physical activity, body weight and other health factors can influence a person's risk.

Gestational diabetes develops when pregnancy-related changes in hormone activity interfere with insulin function.

There is no single cause that explains every case. A person diagnosed with diabetes should not assume that the condition resulted from one particular food, habit or personal decision.

Who Is at Greater Risk of Developing Diabetes?

Risk factors differ between the types of diabetes.

For type 1 diabetes, having a close family member with the condition may increase risk, although many people diagnosed with it have no known family history.

For type 2 diabetes, recognised risk factors include:

• A family history of diabetes.
• Increasing age, particularly from 35 years onward.
• Physical inactivity.
• Excess body weight.
• Prediabetes, in which blood glucose is higher than normal but below the diagnostic range for diabetes.
• A history of gestational diabetes.
• Certain hormonal conditions, including polycystic ovary syndrome.
• High blood pressure and other metabolic health problems.

Children and younger adults can also develop type 2 diabetes, so age alone does not rule out the condition.

People with recognised risk factors may benefit from discussing blood glucose screening with a healthcare professional. Testing can identify diabetes before significant symptoms or complications develop.

How Is Diabetes Diagnosed?

Diabetes is diagnosed using blood tests that measure glucose levels or estimate average blood glucose over time. A healthcare professional selects the appropriate test according to the person's symptoms and circumstances.

Fasting Blood Glucose Test

This test measures blood glucose after a period without food, usually overnight. It helps determine whether glucose levels are within the normal range or elevated.

HbA1c Test

The HbA1c test estimates average blood glucose over approximately the previous two to three months. It can help identify diabetes and monitor how well blood sugar is being managed.

Oral Glucose Tolerance Test

During this test, blood glucose is measured before and after the person drinks a glucose-containing solution. The results show how effectively the body processes glucose.

This test is also used in the assessment of gestational diabetes.

Random Blood Glucose Test

A random blood glucose test measures sugar levels without requiring fasting. In someone with typical symptoms, a sufficiently high result may help establish the diagnosis.

The interpretation of these tests depends on established medical thresholds and clinical circumstances. Some results require confirmation with repeat testing, particularly when symptoms are absent.

Early diagnosis allows treatment to begin before prolonged high blood glucose causes further damage.

How Is Diabetes Treated?

Diabetes treatment aims to manage blood glucose levels, reduce symptoms and prevent or delay complications. The treatment plan depends on the type of diabetes, the person's age, general health and response to treatment.

Insulin Treatment

People with type 1 diabetes require insulin because their bodies cannot produce enough of the hormone. Insulin may be administered through injections or an insulin pump.

Some people with type 2 diabetes also need insulin when other treatment approaches are insufficient or when their medical circumstances require it.

Insulin treatment must be carefully managed because both high and low blood glucose levels can cause serious health problems.

Medicines for Type 2 Diabetes

Several medicines can help people with type 2 diabetes control their blood glucose. Some improve the body's response to insulin, while others influence how the body produces or processes glucose.

The appropriate medicine depends on the individual's blood glucose levels, other medical conditions, potential side effects and treatment goals.

People should take prescribed medicines according to their healthcare professional's instructions and should not stop treatment or change doses without medical advice.

Healthy Eating

A balanced eating pattern can support blood glucose management. It generally includes vegetables, fruits, whole grains, beans, appropriate protein sources and other nutritious foods in suitable portions.

Reducing excessive intake of sugary drinks and foods high in added sugar can help support overall health. The most suitable eating plan varies between individuals, particularly for those taking medicines that can cause low blood glucose.

People with diabetes do not necessarily need to eliminate every carbohydrate-containing food. Rather, they benefit from an eating plan suited to their medical needs and daily routine.

Physical Activity

Regular physical activity can improve the body's response to insulin and support blood glucose management. Walking, cycling, swimming and other activities suited to a person's abilities may be beneficial.

The appropriate activity level depends on age, general health, existing complications and treatment. People with medical conditions that affect exercise safety should seek guidance from their healthcare team.

Monitoring Blood Glucose

Some people need to check their blood glucose regularly using a home glucose meter or a continuous glucose monitoring device.

Monitoring can help show how food, activity, illness and medicines affect blood sugar. The frequency of testing depends on the person's treatment plan and medical circumstances.

Regular follow-up appointments also allow healthcare professionals to review results and make adjustments when necessary.

Complications Associated With Diabetes

When blood glucose remains elevated over a long period, it can damage blood vessels and nerves throughout the body. The risk of complications depends on several factors, including glucose control, blood pressure, cholesterol levels and the duration of the condition.

Heart Disease and Stroke

Diabetes increases the risk of cardiovascular disease. Damage to blood vessels and the presence of other risk factors can contribute to heart attacks and strokes.

Managing blood glucose, blood pressure and cholesterol can help reduce these risks.

Kidney Disease

High blood glucose can damage the small blood vessels in the kidneys, affecting their ability to filter waste from the blood.

Regular kidney function tests and appropriate treatment can help identify problems before they become severe.

Eye Problems

Diabetes can damage the blood vessels in the retina, the light-sensitive tissue at the back of the eye. This condition, known as diabetic retinopathy, can lead to vision loss if it progresses without appropriate care.

Regular eye examinations can help identify changes early.

Nerve Damage

Diabetic neuropathy occurs when elevated blood glucose damages nerves. It can cause pain, tingling, burning sensations or reduced feeling, particularly in the feet and hands.

Reduced sensation can make it harder to notice injuries, increasing the risk of wounds and infections.

Foot Problems

Poor circulation and nerve damage can make foot injuries more difficult to detect and heal. In severe cases, untreated ulcers and infections may lead to serious tissue damage.

People living with diabetes should inspect their feet regularly and seek medical attention for wounds, swelling, colour changes or signs of infection.

Other Complications

Diabetes can also increase the risk of certain infections and contribute to oral health problems. The risk of complications can be reduced through appropriate treatment, regular screening and management of other health conditions.

Can Diabetes Be Prevented?

The answer depends on the type.

Type 1 diabetes cannot currently be prevented using established lifestyle measures. Researchers continue to investigate the factors involved in its development.

Many cases of type 2 diabetes can be prevented or delayed through a combination of healthy eating, regular physical activity and maintaining a weight appropriate for the individual's health.

Other useful measures include avoiding tobacco, attending recommended health checks and managing conditions such as high blood pressure.

Gestational diabetes cannot always be prevented. However, appropriate prenatal care and healthy habits before and during pregnancy can support maternal health. Screening remains important because the condition may develop without obvious symptoms.

Prevention measures reduce risk but do not guarantee that a person will never develop diabetes.

Living With Diabetes

A diabetes diagnosis does not mean a person cannot lead an active and fulfilling life. Many people manage the condition through a combination of medical treatment, monitoring, nutrition, physical activity and regular healthcare appointments.

Learning how diabetes affects the body helps individuals recognise changes in blood glucose and understand the purpose of their treatment.

Family members and caregivers can offer useful support by encouraging healthy routines, helping with appointments when needed and avoiding blame or stigma.

People living with diabetes should also attend recommended eye examinations, kidney assessments, foot checks and other screening appointments. These measures can help detect complications early.

The treatment plan may change over time as a person's health, medication needs and daily circumstances change.

When Does Diabetes Require Urgent Medical Attention?

Certain symptoms may indicate a dangerous diabetes-related emergency.

Severe thirst and frequent urination accompanied by vomiting, abdominal pain, rapid or deep breathing, confusion or unusual drowsiness can be signs of a serious condition called diabetic ketoacidosis. It occurs when the body produces excessive ketones because it cannot use glucose adequately. It is particularly associated with type 1 diabetes but can also occur in some people with type 2 diabetes.

Another emergency, called hyperosmolar hyperglycaemic state, can occur when blood glucose becomes extremely high and causes severe dehydration and changes in consciousness.

Very low blood glucose can also be dangerous, especially in people taking insulin or certain diabetes medicines. Symptoms may include shaking, sweating, dizziness, confusion or loss of consciousness.

Anyone experiencing severe symptoms, confusion, difficulty breathing or unconsciousness needs emergency medical assistance. A person should not wait for a routine appointment when a diabetes-related emergency is suspected.

Diabetes is a chronic condition that affects how the body produces or uses insulin and regulates blood glucose. Its main forms are type 1 diabetes, type 2 diabetes and gestational diabetes, each with different causes, risk factors and treatment requirements.

Common symptoms include excessive thirst, frequent urination, fatigue, blurred vision and unexplained weight loss. However, type 2 diabetes and gestational diabetes can develop without obvious warning signs, making appropriate screening important.

Although diabetes can lead to serious complications, early diagnosis, suitable treatment and regular medical monitoring can reduce many of these risks. Healthy eating and physical activity are important parts of diabetes care, but they do not replace prescribed medication when it is needed.

Recognising symptoms, understanding personal risk factors and seeking professional medical advice are important steps towards protecting long-term health.