About Diabetes


The World Health Organization (WHO) defines diabetes as: “an illness that occurs when the pancreas does not produce enough insulin, or when the body cannot effectively use the insulin it produces” 1. This in turn leads to a high level of sugar (glucose) in the blood (called hyperglycemia).

According to the WHO, more than 220 million people worldwide have diabetes and almost half of the deaths related to diabetes occur in people under the age of 70 years. In 2005, an estimated 1.1 million people died from diabetes and this figure is expected to double between 2005 and 2030.

In New Zealand (total population 4.3 million with 70% Caucasian, 7.9% Maori, 5.7% Asian, 4.4% Pacific peoples, 7.8% mixed, 3.8% unspecified) the Ministry of Health estimates that 210, 000 people will be affected with diabetes by 2010 2. Certain ethnic groups (particularly Maori, Pacific Islanders and South Asians) are at a higher risk of developing diabetes and data from 1996 suggested that the incidence of diabetes for Maori and Pacific peoples are more than three times higher than the European rates and Maori and Pacific peoples are more than five times as likely to die from diabetes 2.

Given New Zealand’s multi-cultural population and the higher susceptibility of certain ethnic groups to develop diabetes, it is important to consider the prevalence of diabetes in different ethnic groups. Estimated diabetes prevalence data for 2010 in persons over the age of 15 of different ethnic groups are as follows: South Asians 12.4%, Maori 7.8%, Pacific peoples 11.6%, Caucasians 5.3% and a national average of 6.1% 2.

Obesity commonly leads to diabetes and this growing and serious health problem needs mentioning. 25% of adults in New Zealand meet the criteria for obesity and some ethnic groups tend to be affected more than others (e.g. 42% of Maori and 63.7% of Pacific peoples meet the criteria for obesity) 2. Childhood obesity is also increasing and current data shows that 8.3% of children in New Zealand are obese and 20.9% meet the criteria for being overweight 2.

If the current trend is to continue, it is expected that the number of people with diabetes will double over the next 20 years. 3 Because of the serious complications of diabetes, it is one of the 13 immediate action priority objectives for population health in the New Zealand Health Strategy 2.

What is diabetes?

Glucose is the primary source of energy for many of the body’s functions and is obtained from carbohydrates from food and is also made by the liver from fats and proteins. Insulin is a chemical (hormone) in the body that controls the level of glucose in the blood by transporting glucose into cells of the body for storage or use. Insulin also controls the production of glucose by the liver. Broadly speaking, diabetes can occur in three primary forms 5:

  • Type 1 diabetes mellitus – Typically has an onset in childhood (but young adults and older people could develop this condition too) and is characterized by a rapid loss of weight. It is thought to arise as a result of the body’s immune system attacking and destroying the cells of the pancreas that produces insulin 5. As people with this type of diabetes cannot produce insulin, they cannot control their blood sugar levels without receiving injections of insulin.
  • Type 2 diabetes mellitus – This type is much more common than type 1 diabetes (around 90% of worldwide cases of diabetes are thought to be type 2) 1. It is thought to arise when the body is not responding properly to insulin (called insulin resistance) or when the body is not producing enough insulin to control the blood glucose level 4. Previously it was thought that this type mainly affects adults, but increasing numbers of children are now affected 1. Increased childhood obesity is the major risk factor 5 for developing this type of diabetes and management involves lifestyle and diet modification in the first instance. Most people with this type subsequently need medications and insulin as part of their management as the disease progresses.
  • Gestational diabetes mellitus – This type arises during pregnancy when the body is not able to bring high blood sugar levels to normal effectively by producing adequate insulin. High blood sugar levels in pregnancy can have adverse effect on the unborn baby and can also lead to complications with childbirth. In addition to careful monitoring and dietary modifications, some mothers will also require tablets or insulin injections as part of their management during pregnancy. There is a much higher likelihood of these mothers developing type 2 diabetes later 5.

Diabetes (types 1 and 2) requires life long care but current management strategies allow people to live a full and active life.

Complications of diabetes

Diabetes has many effects on the body 1:

  • Increased risk of heart disease and stroke (50% of people with diabetes die from cardiovascular disease)
  • Nerve and blood vessel damage increase the chances of ulcers and the need for limb amputation
  • Damage to the blood vessels of the eyes, possibly leading to blindness (diabetic retinopathy). After 15 years of having diabetes, approximately 2% of people become blind.
  • Damage to the kidneys can lead to kidney failure and 10-20% of people with diabetes die of kidney failure (These complications are particularly common in Maori and Pacific peoples of New Zealand 2)
  • Up to 50% of people with diabetes have some type of nerve damage (diabetic neuropathy) and experience tingling, pain, numbness or weakness in the feet and hands.

Although there is potential for serious complications, early diagnosis and appropriate management of diabetes can considerably reduce the risk of these problems.


[1] World Health Organization:


[2] Ministry of Health:


[3] The Diabetes Research Institute:


[4] Diabetes New Zealand:


[5] American Diabetes Association:



Compiled by Ajith Dissanayake (endocrinologist) from Counties Manukau District Health Board