Nearly one in five New Zealanders over the age of 15 have a blood disorder that precedes Type 2 diabetes, a finding described as "alarming" by experts.
The finding came from a University of Otago study involving blood sampling of 4721 Kiwis aged 15 years and older, which showed 19 per cent had glucose metabolism disorder. The pre-diabetes disorder typically leads to the disease.
Lead researcher Dr Kirsten Coppell from the university's Edgar National Centre for Diabetes and Obesity Research said she was shocked at the high prevalence of pre-diabetes.
"These data, when compared with the first measurements taken in 1967, provide convincing evidence that the prevalence of diabetes in New Zealand has increased over time. This is consistent with observations worldwide."
Diabetes New Zealand national president Chris Baty agreed.
"It probably confirms our worst fears that have been collectively held in the diabetes community.
The incidence and the increase in New Zealand is completely and utterly alarming," she said.
More than 200,000 Kiwis have diabetes, mostly Type 2, which is linked to obesity.
The blood samples came from the 2008/2009 NZ Adult Nutrition Survey, conducted by Otago University researchers for the Ministry of Health. The study also found that the prevalence of pre-diabetes and diabetes also continued to rise with age, increasing from almost 20 per cent of those aged 35-44 to more than 25 per cent for those aged 45-54 and almost 45 per cent for those aged 55-64 years.
Diabetes is most common among Pacific Islanders and Maori, who are three times as likely to get it as other New Zealanders. The prevalence is also higher among those who are obese.
A combination of factors contributed to Type 2 diabetes but there was a "very clear link between obesity and the establishment of diabetes", Ms Baty said.
"It's impacting people younger and it's causing huge morbidity. People have got to realise that our lifestyle is killing us."
Eating less processed food and exercising more were positive lifestyle changes that could help improve the statistics.
Dr Coppell said the pre-diabetes rates added to an already-high national diabetes rate and should be a major concern to policymakers and health funders.
"The implications of increased diabetes-related morbidity, mortality and health care costs are considerable," she said.
"Implementation of effective evidence-based diabetes prevention strategies is urgently required to reduce the increasing costs of the diabetes epidemic."
The study was published in the New Zealand Medical Journal.
What is it?
A disease where the body cannot control its blood sugar levels properly either because it doesn't make enough insulin or because cells have become resistant to insulin.
Diabetes can lead to other health conditions, including kidney failure, eye disease, foot ulceration, a higher risk of heart disease and can be life-threatening.
Who is affected?
More than 200,000 New Zealanders have diabetes, most of them are Type 2.
Types of diabetes
Type 1 is an auto immune disease in which the body has stopped producing insulin and requires sufferers to inject insulin to live.
Type 2 diabetes is a lifelong disease in which there are high levels of glucose in the blood and is linked to obesity.
Source: Ministry of Health