Diabetes is a chronic condition that occurs when the pancreas can no longer make insulin, or the body cannot effectively use insulin.

Insulin is a hormone made by the pancreas that acts like a key to let glucose from the food we eat pass from the bloodstream into the cells in the body to produce energy. The body breaks down all carbohydrate foods into glucose in the blood, and insulin helps glucose move into the cells.

When the body cannot produce or use insulin effectively, this leads to high blood glucose levels, called hyperglycaemia. Over the long-term high glucose levels are associated with damage to the body and failure of various organs and tissues.

Diabetes facts and figures show the growing global diabetes burden for individuals, families and countries. The latest International Diabetes Federation (IDF) Diabetes Atlas (2025) reports that 11.1%  (or 1 in 9) of the adult population (20-79 years) is living with diabetes, with over 4 in 10 unaware that they have the condition.

Symptoms of diabetes may occur suddenly. In type 2 diabetes, the symptoms can be mild and may take many years to be noticed.

Symptoms of diabetes include:

• Feeling very thirsty
• Needing to urinate more often than usual
• Blurred vision
• Feeling tired
• Losing weight unintentionally

Over time, diabetes can damage blood vessels in the heart, eyes, kidneys and nerves.

People with diabetes have a higher risk of health problems including heart attack, stroke and kidney failure.

Diabetes can cause permanent vision loss by damaging blood vessels in the eyes.

Many people with diabetes develop problems with their feet from nerve damage and poor blood flow. This can cause foot ulcers and may lead to amputation.

Type 1 diabetes (previously known as insulin-dependent, juvenile or childhood-onset) is characterized by deficient insulin production and requires daily administration of insulin. In 2017, there were 9 million people with type 1 diabetes; the majority of them live in high-income countries. Neither its cause nor the means to prevent it are known.

Type 1 diabetes is an autoimmune condition where the body stops producing insulin, a hormone essential for regulating blood sugar. Because of this, insulin therapy is the cornerstone of treatment and must be taken daily, either through injections or an insulin pump.

Managing type 1 diabetes also involves:

• Monitoring blood sugar regularly using finger-prick blood tests or continuous glucose monitors (CGMs)
• Counting carbohydrates to match insulin doses with food intake
• Staying active and maintaining a healthy lifestyle to support overall health
• Attending regular check-ups to monitor for complications and adjust treatment

Some people may also use advanced technologies like closed-loop systems (artificial pancreas) to automate insulin delivery. Education, support, and consistent care are key to living well with type 1 diabetes.

Type 2 diabetes affects how your body uses sugar (glucose) for energy. It stops the body from using insulin properly, which can lead to high levels of blood sugar if not treated.

Over time, type 2 diabetes can cause serious damage to the body, especially nerves and blood vessels.

Type 2 diabetes is often preventable. Factors that contribute to developing type 2 diabetes include being overweight, not getting enough exercise, and genetics.

Early diagnosis is important to prevent the worst effects of type 2 diabetes. The best way to detect diabetes early is to get regular check-ups and blood tests with a healthcare provider.

Symptoms of type 2 diabetes can be mild. They may take several years to be noticed.  Symptoms may be similar to those of type 1 diabetes but are often less marked. As a result, the disease may be diagnosed several years after onset, after complications have already arisen.

More than 95% of people with diabetes have type 2 diabetes. Type 2 diabetes was formerly called non-insulin dependent, or adult onset. Until recently, this type of diabetes was seen only in adults, but it is now also occurring increasingly frequently in children.

Gestational diabetes is hyperglycaemia with blood glucose values above normal but below those diagnostic of diabetes. Gestational diabetes occurs during pregnancy.

Women with gestational diabetes are at an increased risk of complications during pregnancy and at delivery. These women and possibly their children are also at increased risk of type 2 diabetes in the future.

Gestational diabetes is diagnosed through prenatal screening, rather than through reported symptoms.

Impaired glucose tolerance (IGT) and impaired fasting glycaemia (IFG) are intermediate conditions in the transition between normality and diabetes. People with IGT or IFG are at high risk of progressing to type 2 diabetes, although this is not inevitable.

Lifestyle changes are the best way to prevent or delay the onset of type 2 diabetes.

To help prevent type 2 diabetes and its complications, people should:

• Reach and keep a healthy body weight
• Stay physically active with at least 150 minutes of moderate exercise each week
• Eat a healthy diet and avoid sugar and saturated fat
• Not smoke tobacco.

Early diagnosis can be accomplished through relatively inexpensive testing of blood glucose. People with type 1 diabetes need insulin injections for survival.

One of the most important ways to treat diabetes is to keep a healthy lifestyle.

Some people with type 2 diabetes will need to take medicines to help manage their blood sugar levels. These can include insulin injections or other medicines. Some examples include:

• Metformin
• Sulfonylureas
• Sodium-glucose co-transporters type 2 (SGLT-2) inhibitors

Along with medicines to lower blood sugar, people with diabetes often need medications to lower their blood pressure and statins to reduce the risk of complications.

Additional medical care may be needed to treat the effects of diabetes:

• Foot care to treat ulcers
• Screening and treatment for kidney disease
• Eye exams to screen for retinopathy (which causes blindness).

When oral medications and lifestyle changes no longer keep blood sugar levels under control, insulin therapy becomes a vital next step in managing type 2 diabetes. This transition is not a sign of failure, it reflects the progressive nature of the disease, where the pancreas gradually loses its ability to produce enough insulin. Starting insulin at the right time helps restore glycemic control, reduce the risk of complications, and improve overall well-being. Delaying insulin therapy can lead to prolonged high blood sugar, increasing the risk of nerve damage, kidney disease, and heart problems. Insulin can be introduced gradually, often starting with a single daily dose of long-acting insulin while continuing oral medications. Over time, the regimen may be adjusted to include mealtime insulin if needed. With modern delivery devices and support from healthcare teams, insulin therapy is more manageable than ever, and it can be life-changing for those who need it

Since its discovery in 1922, insulin production has evolved from animal-derived insulin to biosynthetic human insulin (BHI), insulin analogues, and most recently, biosimilar insulins. Today, insulin therapy includes four main types: basal (long-acting), bolus (rapid-acting), mixed, and intermediate-acting insulins, each differing in onset, peak, and duration. Rapid-acting insulins work within 15 minutes, while long-acting insulins provide steady coverage for up to 24 hours. Insulin regimens vary by diabetes type: people with type 1 diabetes often use both basal and bolus insulins, while those with type 2 may use insulin alone or with other medications. Gestational diabetes is typically managed with rapid-acting and sometimes long-acting insulin. Intensive insulin therapy mimics natural insulin patterns and offers flexibility, while sliding scale therapy adjusts doses based on blood glucose levels. Advances in insulin types and delivery methods have significantly improved diabetes management and quality of life.

People living with diabetes have an increased risk of developing diabetes complications. The most common are those that affect the heart, blood vessels, eyes, kidneys, nerves, teeth and gums. 

In high-income countries, diabetes is a leading cause of cardiovascular disease, blindness, kidney failure and lower limb amputation. Managing blood glucose, blood pressure and cholesterol levels can delay or prevent complications. Regular monitoring of these signs is therefore essential for people with diabetes