Type 2 diabetes

Type 2 diabetes is a condition in which your body isn't able to use insulin properly, resulting in high blood glucose levels. This can lead to a wide range of health problems if not treated.

Unlike type 1 diabetes, the pancreas in people with type 2 diabetes is able to make insulin. The main problem with type 2 diabetes is that the body doesn't respond to insulin the way it should. This is known as insulin resistance. 

Type 2 diabetes is a progressive disease, which means it slowly gets worse with time. This is because the cells that produce insulin in our pancreas continue to be damaged or die and our bodies are less able to make enough insulin to balance the blood glucose.This means people with type 2 diabetes can also experience insulin deficiency and may require insulin injections.

Diabetes - overview & symptoms – part of a series of 10 short videos about diabetes.

Key Points:

  1. Diabetes is common and many people do not know they have it. Check with your nurse or doctor about when you need a screening test.
  2. 80% of all type 2 diabetes is preventable if we keep to a healthy body weight, eat healthier foods and keep physically active.
  3. Early treatment is important to reduce damage to your eyes, kidneys, heart, feet and brain.
  4. Know what your HbA1c, blood pressure and cholesterol are.
  5. While diabetes is a progressive condition, attending a diabetes self management course, learning as much as you can about diabetes and watching this series of Diabetes Videos can help you to live well with diabetes.
  6. See your doctor/nurse every 3 months or more for regular check-ups, not just when something is wrong.

What is diabetes?

Diabetes is having too much of a type of sugar called glucose in the blood. This can happen either because the pancreas cannot make enough insulin or your body is not responding to the insulin as it should. Insulin is a natural hormone which helps glucose enter the body's cells, where it is used for energy. If there is not enough insulin or it is not working well to open the channel for glucose to enter the cells, glucose builds up in the bloodstream.

When someone has diabetes, their body is not able to control their blood glucose levels and keep it in the safe range.

  • If the level is too low, low blood glucose, or hypoglycaemia, occurs and people feel sweaty, weak and dizzy and need to eat some glucose right away.
  • If too high, high blood glucose, or hyperglycaemia, can occur.

Symptoms depend on how high or rapidly the level changes but can include excess thirst, passing excess urine, blurred vision etc.

While diabetes cannot be cured, it can be controlled and people with diabetes can lead a full and active life.

Who is at risk of type 2 diabetes?

If you have any of the following risk factors, check with your doctor/nurse about a test for diabetes:

  • you are overweight for your height. Use our BMI calculator
  • a family member has diabetes
  • you are Maori, Pacific or Asian and aged 35 or over
  • you aged 45 year or over.


About 50% of people with type 2 diabetes have no symptoms or have not been diagnosed. Others may:

  • feel very thirsty
  • pass a lot of urine
  • feel very tired
  • have blurred vision
  • have urinary infections, skin infections
  • find cuts and grazes heal slowly.

If you have one or more risk factors for diabetes, or any of the symptoms above, see your doctor or nurse for a check up.

It is easy to test for diabetes and important to find out so you can take action to prevent damage to your eyes, heart, kidneys and feet.


Screening tests

If you have symptoms of diabetes, your doctor or nurse will send you to the lab for a blood test. If you don't have any symptoms, signs of diabetes may be picked up as part of a heart check or other routine screening test.

A  glycated haemoglobin (HbA1c) is the recommended test for both screening and diagnosing diabetes. This needs to be done by at a specialised laboratory. Finger prick tests at community health centres are not accurate enough for diagnosing diabetes.

If it is not possible to measure HbA1c, or there are other issues to be considered, then a fasting plasma glucose is recommended.

Diagnostic tests

Since 2011, the diagnosis of diabetes is made on the basis of a lab test measuring either HbA1c or venous plasma glucose measurements. 

If you have symptoms of diabetes an HbA1c ≥50 mmol/mol (and, if measured, a fasting blood glucose ≥7.0 mmol/l or a random glucose ≥ 11.1 mmol/l) is sufficient to establish the diagnosis of diabetes.

If you do not have symptoms of diabetes the same criteria apply but, to confirm the diagnosis of diabetes, a confirmatory test (preferably HbA1c) is needed on a separate occasion.

A HbA1c of ≤40 mmol/mol is normal.

   Normal Pre-diabetes Diabetes
HbA1c ≤40 mmol/mol 41–49 mmol/mol ≥50 mmol/mol
Fasting blood glucose   6.1–6.9 mmol/l ≥7.0 mmol/l
Random glucose     ≥ 11.1 mmol/l


If your HbA1c level is 41–49 mmol/mol or a fasting glucose concentration is slightly high at 6.1–6.9 mmol/l, you may be told that you have pre-diabetes.

If you have prediabetes, it is important to review your diet, blood pressure, physical activity levels and other clinical measures with your doctor or nurse. With some changes, you can lower your risk of getting diabetes. Your HbA1c measurement should be repeated after 6-12 months. Read more about prediabetes...

Treatment for type 2 diabetes

Type 2 diabetes is treated mainly with oral medication or tablets, which include:

New medications are being developed, but not all are currently funded. Your doctor or nurse will talk with you about which one is best for you.

Read more about diabetes medications


With time, many people with type 2 diabetes will need to also use insulin injections. This can improve control of blood glucose levels and reduce the risk of developing complications.

  • The insulin you get from the chemist is manufactured in the laboratory. It is made to mimic the action of the hormone called insulin that occurs naturally in your body.
  • It is made by joining cell organisms with the human gene for making insulin joined. These cells are then able to make insulin.
  • The human insulin is a very safe product to take and there have been no instances of insulin becoming contaminated with anything harmful.
  • Insulin is injected just under the skin, not in a vein.

The common ways of using insulin for type 2 diabetes include:

  • Once a day insulin – often at bedtime.
  • Two times a day insulin – given morning and evening.

Read more about starting insulin from the booklet Starting insulin in type 2 diabetes (Waitematā DHB) available in 5 languages including Samoan and Tongan. 

Avoid diabetes complications

Diabetes increases the risk of many serious conditions such as poor vision, heart disease or stroke, damage to our kidneys (diabetes is the top cause of kidney failure), erectile dysfunction and loss of limbs. The key factor affecting how fast or slowly these complications develop is how well or poorly controlled your diabetes is. The best way to avoid or delay developing diabetes-related health problems is by keeping your blood glucose and blood pressure levels within the healthy range.

specialist talking about diabetes complications

See: blood glucose testing


There are many groups and people keen to share their knowledge and tips for living well with diabetes. Diabetes NZ has branches around the country with a wide range of services, resources, groups and shops. 

Regional diabetes support

Learn more

Diabetes NZ
Diabetes UK