What happens in the body
Unlike type 1 diabetes, in type 2 diabetes the pancreas usually keeps producing insulin early in the disease — often even more than in healthy people — as it tries to compensate for reduced tissue sensitivity. Over time this compensation is exhausted, and blood glucose levels rise persistently. This condition used to be called "non-insulin-dependent diabetes" or "adult-onset diabetes," though today it's increasingly diagnosed in younger age groups too.
Global prevalence
According to the WHO, around 830 million adults worldwide had diabetes (all types and age groups) in 2022 — compared with 200 million in 1990. The IDF Diabetes Atlas (11th edition, 2025) cites a somewhat different figure — 589 million adults aged 20–79, or roughly one in nine adults worldwide — projected to grow to 853 million by 2050. These figures differ because of different age ranges and counting methodologies, so they shouldn't be compared directly. Historically, case numbers rose sharply: about 30 million in 1985, 135 million in 1995, 217 million in 2005, and 392 million in 2015.
Causes and risk factors
Excess weight or obesity and low physical activity are considered the main risk factors. The contribution of excess weight to the disease varies significantly between populations: estimates suggest around 30% among people of Chinese and Japanese descent, 60–80% among people of European and African descent, and nearly 100% among some Indigenous populations (such as the Pima or Pacific Islanders). Other factors include:
- heredity — estimated at around 72%, with more than 36 genes linked to risk identified;
- a family history of type 2 diabetes;
- age over 45 (though it's increasingly diagnosed in younger people too);
- a history of gestational diabetes;
- high intake of sugary drinks, saturated fat, and trans fat;
- chronic stress, poor sleep, smoking;
- high blood pressure and abnormal lipid levels.
Symptoms
The main difference from type 1 is a slow, often unnoticeable onset. Many people have no symptoms for years, and the disease is discovered by chance during a routine blood test. When symptoms do appear, they include:
- increased thirst and frequent urination;
- persistent hunger, fatigue;
- blurred vision;
- slow-healing cuts and wounds, frequent infections;
- numbness or tingling in the hands and feet;
- darkened, thickened patches of skin on the neck, armpits, or groin (acanthosis).
Course and possible complications
Researchers estimate that poorly controlled type 2 diabetes is associated with a reduction in life expectancy of roughly 10 years on average. The disease raises the risk of cardiovascular events 2–4 fold, is a leading cause of non-traumatic lower-limb amputation (with risk rising, by some estimates, up to 20-fold), vision loss from retinopathy, and kidney failure. According to the WHO, diabetes caused 1.6 million deaths directly in 2021, with another roughly 530,000 deaths linked to diabetes-related kidney disease, and elevated glucose contributing to about 11% of cardiovascular deaths worldwide. The acute complication known as hyperosmolar hyperglycemic state occurs less often than ketoacidosis does in type 1 diabetes, but it also requires emergency care. Read more on the diabetes complications page.
How it's typically managed medically
The first line of management is usually lifestyle change: diet, physical activity, and weight control. Studies cited by Wikipedia show that significant weight loss (roughly 15 kg or more in people with obesity) was associated with disease remission in some cases — this is presented as a research finding, not a general recommendation. If lifestyle changes aren't enough, medication is prescribed: metformin is usually mentioned as the first-line drug, and other drug classes are also used (GLP-1 receptor agonists, SGLT2 inhibitors, sulfonylureas, and others). In later stages, insulin therapy may be needed. The standard of care includes regular monitoring of glucose and HbA1c, along with screening for complications (eyes, kidneys, feet, cardiovascular system).