A ''tsunami'' of diabetes cases is set to hit Rotorua as new data highlights the state of the disease in the Lakes region.
Lakes District Health Board estimates the number of people with type 2 diabetes in the Lakes area will double in two decades.
It comes after the release of a PwC report commissioned by Diabetes New Zealand, the University of Otago's Edgar Diabetes and Obesity Research Centre and Healthier Lives National Science Challenge, which predicts a bleak outlook.
The $2.1 billion spent treating those with diabetes is projected to increase by 63 per cent to $3.5b in 20 years due to the number of Kiwis with type 2 diabetes rising by as much as 90 per cent by 2041.
A shift towards younger people developing the disease and worse health outcomes for minorities would happen if "no action is taken now", the report states.
However, there were four interventions that could save hundreds of millions of dollars each, increase life expectancy and improve quality of life for a huge number of New Zealanders.
Lakes District Health Board lifestyle consultant Dr Hayden McRobbie said 5.3 per cent of the health board population had diabetes, according to the most recent data.
"This equates to 5943 people. This rate is similar to the prevalence of diabetes in the New Zealand population."
The number is made up of people predominantly with type 2 diabetes - it is estimated 10 per cent of all people with diabetes have type 1, the Ministry of Health said. The data includes both type 1 and 2 diabetes.
Type 1 is an auto-immune disease while type 2 will develop most commonly in people's late 30s, but both affect the body due to the lack of insulin produced to keep glucose levels low.
"If we apply the estimated projected increase in type 2 diabetes, then we could expect that the number of people living in the Lakes DHB region with diabetes to almost double by 2040."
McRobbie said the projected number was "concerning".
"There is a range of different factors that will contribute to this projected increase in type 2 diabetes.
"Lifestyle factors, for example, play an important role in the development of diabetes, with obesity being a significant factor. Unhealthy eating and physical inactivity, as well as excess alcohol consumption, are all associated with an increased risk of obesity."
The Lakes District Health Board could not confirm the cost of treating the disease but said it was associated with significant costs.
McRobbie said there were lifestyle factors that made developing type 2 diabetes less likely, but it wasn't a "personal health problem".
"The environment in which we live also influences our health. Societal changes are also needed."
This thought was shared by Korowai Aroha chief executive Hariata Vercoe, who described the state of diabetes in Rotorua as a "tsunami of disease that is coming down on us".
Her team predicted a yearly 10 per cent increase in diabetes diagnoses at Korowai Aroha.
"While we can make, or try and encourage people to make, better dietary decisions or better lifestyle decisions, we're also aware of the poverty level and the social problems that people are facing."
This resulted in many holding their own health at the bottom of their priority list, she said.
"So we can actually understand the reasons why there is this increase in the diabetes numbers coming through. Most people aren't focusing on their own health needs, they're focusing on the other problems that are quite prevalent."
People needing to "eat better" or become "more active" was a simplistic way of looking at the problem, Vercoe believed.
"We know there is a burden on people's financial situation and access to fresh fruit is usually a dearer option where you can get noodles, which seems more affordable."
Three Lakes Clinic general practitioner Cate Mills believed people lacked time, which contributed to unhealthy or convenient choices.
However, the predicted rate greatly concerned Mills and she said something needed to change.
"I find that alarming on two levels really. One, the level of what it's going to mean for all those people that are going to suffer from diabetes, but also what that's going to mean for our health system, and in all the diabetic complications that are going to arise from this."
The number of diabetics would be a "huge burden" on the health system and with population numbers rising and life expectancy lengthening, the biggest modifiable risk was people's weight, Mills said.
Type 2 diabetes is a disease Merlene Whyte has been battling for 12 years. It has only been in recent months that she has felt it is under control.
"I struggled for a long time to get things sorted and work out what was good for me or not, but now I have finally conquered it I hope - it's taken a long time."
The Rotorua woman had to give up on many treats people take for granted including fish and chips, and fizzy drinks. Now she has to prick her finger three times a week to ensure her blood levels are behaving.
Her disease is constantly front and centre of her mind and Whyte said she was envious of those who did not have to worry - although she wasn't shocked to hear diagnosis rates were expected to double in two decades.
"I can see why it's gonna happen - it's about the food. People say they are too busy but surely they have the weekends where they could do some meals and put them in the freezer."
She hoped all people would take the disease seriously.
"Make sure you have your blood tests and make sure you go to the doctor. Once you get told you are pre-diabetic you should use your brain and keep eating healthy so you don't become a fully-fledged diabetic."
Diabetes New Zealand Lakes district manager Karen Reed said health services were already struggling to provide adequate care and support for people with diabetes.
Diagnosis rates doubling in two decades was more than concerning, it was alarming, Reed said.
"These projections suggest we are failing our communities when it comes to health messaging."
As numbers continued to rise, the greater investment would help to counter the "devastating effect" the disease would have on communities, she said.
"The report looked at four potential interventions in detail – I'd like to see support to help us put these and more into action – we need more funding, more resources and we need to be creative in using these resources, we need to work collaboratively and we need a New Zealand-wide approach."
Reed worked on the report published last week and said it wasn't about helping people to live healthier lifestyles but taking steps to break down the barriers.
"The food industry has a large part to play in this, schools and workplaces, we need to address social and economic barriers.
"It's not just what we eat or how much we exercise, it's much bigger than that, it's about how we live."
University of Otago's Edgar Diabetes and Obesity Research Centre director, Professor Rachael Taylor, said something needed to change to stem the growing "epidemic".
"Type 2 diabetes is not tracked as a national health target for a start, and yet the figures are growing at an alarming rate.
"All eyes remain on Covid-19 as a major current global health issue, but New Zealand is facing a staggering increase in numbers of people with type 2 diabetes and astronomical costs associated with this disease."
Healthier Lives National Science Challenge director Professor Jim Mann said the industry had known type 2 diabetes was a worrying issue for a long time.
"But we now know that its impact on New Zealand can be measured as a fraction of GDP with the $2.1b annual equivalent to 0.67 per cent of GDP.
"That's just for this one disease and is in purely financial terms, let alone the human cost to individuals and their whānau."
He said while many were aware of the disease, the report revealed the surprising extent of the issue.
Healthy Families Rotorua has been approached for comment.
Concern grows for Hayden Kemp, 40, last seen in Rerewhakaaitu on Friday.