Southern Cross Medical Library

Southern Cross Medical Library

Diabetes is when levels of glucose (sugar) in your blood are too high because your body has insufficient insulin or resists the effects of insulin. Type 1 diabetes is a life-long variation of the disease that typically takes hold in childhood or adolescence but can occur in later years. It is the result of the body’s immune system destroying the pancreas where insulin is made.

Symptoms of type 1 diabetes can appear suddenly and can cause serious health complications over time. However, the condition can be managed with insulin replacement therapy and lifestyle changes.

General information

Diabetes mellitus (commonly referred to as diabetes) is a group of diseases characterised by high blood glucose (sugar) levels over a prolonged period of time. This page deals with type 1 diabetes. Other diabetes variations include type 2 diabetes (associated with a person being resistant to insulin) and gestational diabetes (where a mother cannot produce enough insulin during pregnancy).

Type 1 diabetes used to be known as juvenile diabetes because it most often occurs in childhood, but it can also develop in adults. An estimated 5–10 per cent of people with diabetes in New Zealand have type 1 diabetes. It is more common in New Zealand Europeans than other ethnic groups. Type 1 diabetes accounts for more than 90 per cent of cases of diabetes in childhood and early adolescence and its incidence in children continues to increase over time.


Although the exact cause of type 1 diabetes is unknown, it is generally considered to be an autoimmune condition in which the body's immune system mistakenly attacks and destroys the cells in the pancreas that produce insulin – a hormone that tells your cells when to absorb glucose from your bloodstream and keeps blood sugar from getting too high or too low. Once a critical number of pancreatic cells have been destroyed, the body produces little or no insulin. Without insulin, glucose is not taken up into the cells and blood sugar levels increase.

Risk factors

Certain factors are associated with an increased risk of developing type 1 diabetes. Known risk factors for type 1 diabetes include:

  • Family history: Having a parent or sibling with type 1 diabetes.
  • Genetics: The presence of certain genes.
  • Age: Peak incidence occurs at 4–7 years and at 10–14 years.

Possible risk factors include:

  • Exposure to certain viruses, eg: Epstein-Barr virus, coxsackievirus and other enteroviruses, mumps virus
  • Upper respiratory infections early in life.

Signs and symptoms

The signs and symptoms of type 1 diabetes can appear suddenly. The classic symptoms are:

  • Excessive or constant thirst
  • Frequent urination (peeing)
  • Extreme hunger.

Other signs and symptoms include:

  • Unexplained weight loss
  • Nausea, vomiting, and abdominal pain
  • Fatigue and weakness
  • Blurred vision
  • Irritability
  • Bedwetting in children
  • Vaginal thrush.

A doctor should be seen if any of the above signs and symptoms develop, especially the classic symptoms of diabetes.


In the presence of the classic symptoms of diabetes, the following blood tests will confirm a diagnosis of type 1 diabetes:

  • Random blood glucose test: A blood sample is taken at a random time.
  • Fasting blood glucose test: A blood sample is taken after an overnight fast.
  • Oral glucose tolerance test: A blood sample taken before drinking a mixture of glucose dissolved in water and again 2 hours after.

A blood test called the glycosylated haemoglobin (Hb1Ac) test might also be performed. It is a measure of a person’s average blood glucose level over the past 2–3 months. The Hb1Ac test is also used to monitor the effect of treatment.

Blood tests to check for immune system proteins called islet cell antibodies, which act against the insulin-producing cells in the pancreas, may also be done. These tests help to distinguish between type 1 and type 2 diabetes.

Long-term complications

  • Serious complications of type 1 diabetes that develop gradually over many years include:
  • Heart and blood vessel damage (coronary heart disease)
  • Damage to the nerves (neuropathy)
  • Kidney damage (nephropathy)
  • Damage to the eyes (retinopathy, glaucoma, cataracts)
  • Foot problems (‘diabetic foot’)
  • Skin and mouth problems, including infections like cellulitis
  • Pregnancy complications (for mother and baby).

Maintaining blood glucose levels as close as possible to normal can help to delay or prevent these complications from developing.

Short-term complications

Potentially serious complications of type 1 diabetes that can develop suddenly are:

  • Diabetic ketoacidosis. This occurs when, in the absence of insulin and hence the inability of cells to absorb and metabolise glucose, the body uses fat as an alternative fuel source. This results in a build-up of acids in the blood called ketones. High blood ketone levels can be fatal if not corrected with medical treatment. Signs of ketoacidosis include nausea, vomiting, abdominal pain, and breath that smells sweet/fruity.
  • Low blood glucose (hypoglycaemia): Blood glucose levels can drop for many reasons, eg: missing a meal, injecting too much insulin, or over-exercising. Signs of hypoglycaemia include sweating, shakiness, weakness, hunger, dizziness, headache, blurred vision, slurred speech, drowsiness, confusion, and possibly seizures. Hypoglycaemia requires immediate attention because if left untreated it leads to loss of consciousness. Drinking or eating something sweet/sugary will help to correct a low blood glucose level. Carrying a source of sugar at all times is recommended as is carrying an emergency injection of glucagon, which is a hormone that stimulates the release of sugar into the blood.
  • High blood glucose (hyperglycaemia): Eating too much or not taking enough insulin can result in a blood glucose level that is too high. Signs of hyperglycaemia include frequent urination, increased thirst, dry mouth, blurred vision, fatigue, and nausea. Hyperglycaemia requires correction using an insulin shot or via an insulin pump.


The goal of treatment for type 1 diabetes is to keep blood glucose levels as close to normal as possible. To achieve this, a combination of treatment approaches is required, including:

  • Insulin therapy (insulin replacement)
  • Frequent blood glucose monitoring
  • Carbohydrate counting
  • Eating healthy foods (low-fat high-fibre foods) • Exercising regularly (at least 30 minutes on most days of the week)
  • Maintaining a healthy bodyweight.

Type 1 diabetes requires lifelong insulin therapy, which is why the condition used to be known as insulin-dependent diabetes. Insulin can be given by injection or via a continuous insulin pump.

With insulin injections, a syringe with a fine needle or an insulin pen is used to inject insulin under the skin. Most people require two or more injections of insulin daily with different types of insulin and with doses adjusted based on self-monitoring of blood glucose levels.

An insulin pump is a small device worn on the outside of the body. A tube connects a reservoir of insulin to a catheter that is inserted under the skin of the abdomen. The pump is programmed to dispense specific amounts of insulin.

There are several types of insulin, including:

Rapid-acting insulin: this type of insulin starts working within 15 minutes, reaches peak effect at 60 minutes, and lasts about 2–4 hours. It is injected shortly before meals.

Short-acting insulin: also called regular insulin, this type of insulin starts working around 30 minutes after injection, reaches peak effect at 90–120 minutes, and lasts about 4–6 hours.

Intermediate-acting insulin: also called NPH insulin, this type of insulin starts working in about 1–3 hours, reaches peak effect at 6–8 hours, and lasts 12–24 hours.

Long-acting insulin: this type of insulin has no peak affect and lasts more than 24 hours.

Pre-mixed insulin: this type of insulin is a mixture of short- and intermediate-acting insulins

Blood glucose and ketone monitoring

Optimal diabetic control requires frequent self-monitoring of blood glucose levels as this allows for timely adjustments in insulin doses. People with type 1 diabetes learn how to self-monitor their blood glucose levels using a pocket-sized blood glucose meter and adjust their insulin doses accordingly. Monitoring also shows how different foods affect a person’s blood glucose levels. Recording the results of glucose monitoring in a diabetes diary will show trends over times.

Depending on whether daily insulin injections or an insulin pump is used, blood glucose levels will likely need to be checked at least four times a day. Careful monitoring is the only way to ensure that blood glucose levels remain within the target range.

Blood glucose testing involves using a lancing device to prick the skin to draw a drop of blood, which is placed on a test strip. The test strip is then inserted into a blood glucose meter, which provides a blood glucose level reading. A glucose monitoring device that automatically measures and continuously stores glucose readings without the need for finger pricking and test strips is now available.

Blood ketone meters, which measure blood ketone levels, and work in a similar way to blood glucose devices, are available to test for ketoacidosis.

Lifestyle and home remedies

Careful management of type 1 diabetes is important to reduce the risk of acute and long-term serious complications. The following tips will help:

  • Wear a tag or bracelet that says you have diabetes, in case of an emergency
  • Get yearly physical check-ups and regular eye checks to look for diabetes-related complications
  • Get annual influenza (and possibly pneumonia) vaccinations as high blood glucose levels can weaken the immune system
  • Wash and moisturise your feet daily and check them for blisters, cuts, and sores
  • Control blood pressure and cholesterol levels to help minimise the risk of complications
  • Do not smoke . Smoking increases the risk of complications
  • Drink alcohol responsibly. Alcohol can cause high or low blood glucose levels
  • Minimise stress. Stress hormones may prevent insulin from working properly.

Further information and support

For further information and support contact your doctor, practice nurse, or:

Diabetes New Zealand

Freephone: 0800 DIABETES (0800 342 238)

Email: [email protected]


Diabetes New Zealand provides education and support resources specifically for young New Zealanders with type 1 diabetes and many of its branches around the country host Type 1 youth support groups.

Kids Health



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Mayo Clinic Staff (2022). Type 1 diabetes. Rochester, MN: Mayo Foundation for Medical Education and Research. [Accessed: 07/12/22]

Mayo Clinic Staff (2022). Diabetic ketoacidosis. Rochester, MN: Mayo Foundation for Medical Education and Research. [Accessed: 07/12/22] Mayer-Davis, E.J., et al. ISPAD Clinical Practice Consensus Guidelines 2018: Definition, epidemiology, and classification of diabetes in children and adolescents. Pediatr Diabetes. 2018;19(Suppl. 27):7-19.

Ministry of Health (2022). Diabetes (Web Page). Wellington: New Zealand Ministry of Health.,Zealand%20have%20Type%201%20diabetes [Accessed: 08/12/22]

Willis, J., et al. Type 1 diabetes diagnosed before age 15 years in Canterbury, New Zealand: A 50-year record of increasing incidence. Pediatr Diabetes. 2022;23(3):301-309.

Last reviewed: December 2022


The purpose of the Southern Cross Medical Library is to provide information of a general nature to help you better understand certain medical conditions. Always seek specific medical advice for treatment appropriate to you. This information is not intended to relate specifically to insurance or healthcare services provided by Southern Cross.