Type 2 diabetes is a long-term condition in which the body does not produce enough insulin or cannot use it effectively. Insulin is essential for regulating blood sugar (glucose). When it falls short, glucose rises.
What symptoms can it cause?
- excessive thirst;
- passing urine very often;
- constant hunger;
- tiredness;
- blurred vision;
- wounds that are slow to heal.
Bear in mind that type 2 diabetes may cause no symptoms at all for a long time. So don’t wait for symptoms before having the blood tests your doctor recommends.
Causes and risk factors
In most people, the condition results from a combination of factors:
- genetics and family history;
- a sedentary lifestyle;
- an unhealthy diet;
- excess weight or obesity;
- ageing.
How it is diagnosed
Diagnosis is made with blood tests that measure glucose. The doctor also looks at risk factors, family history and symptoms. According to the American Diabetes Association (ADA) criteria, diabetes is diagnosed when there is:
- glycated haemoglobin (HbA1c) of 6.5% (48 mmol/mol) or higher;
- fasting glucose (after at least 8 hours) of 126 mg/dL (7.0 mmol/L) or higher;
- glucose of 200 mg/dL (11.1 mmol/L) or higher 2 hours after drinking 75 g of glucose (oral glucose tolerance test);
- glucose of 200 mg/dL (11.1 mmol/L) or higher at any time of day in someone with typical symptoms.
Without clear symptoms, two abnormal results, from the same blood sample or from separate samples, are needed to confirm the diagnosis.
Values between normal and diabetes, such as an HbA1c of 5.7 to 6.4% (39–47 mmol/mol) or fasting glucose of 100 to 125 mg/dL (5.6–6.9 mmol/L), indicate prediabetes, a stage at which lifestyle changes can delay or prevent the condition. The ADA recommends screening all adults from the age of 35, and earlier for people with excess weight and other risk factors.
How it is treated
The aim is to control glucose and protect long-term health. Treatment may include:
- changes to diet;
- more physical activity;
- tablets or injectable medicines;
- in some cases, insulin.
Today, the choice of medicines takes into account not only glucose but also each person’s weight, heart and kidneys. Good diabetes control is essential to prevent long-term complications, such as those affecting the eyes, kidneys, nerves and heart.
The key message
Type 2 diabetes can be silent, but it does not have to be out of control. With a timely diagnosis and a plan tailored to you, it can be well controlled.
This article is for information only and does not replace a medical appointment.
References
- American Diabetes Association Professional Practice Committee. 2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1):S27-S49. doi:10.2337/dc26-S002
- American Diabetes Association Professional Practice Committee. 9. Pharmacologic Approaches to Glycemic Treatment: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1):S183-S215. doi:10.2337/dc26-S009
- Davies MJ, Aroda VR, Collins BS, et al. Management of Hyperglycemia in Type 2 Diabetes, 2022. A Consensus Report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetes Care. 2022;45(11):2753-2786. doi:10.2337/dci22-0034
