Type 2 diabetes is Australia's silent assassin, and it's preying on even more of us every year

But should it continue on its current trajectory, the "silent pandemic" of the 21st century stands to affect 700 million people globally within 25 years.

Already, there are 460 million people around the world who have diabetes.

In Australia, it costs the economy as much as $20 billion a year and affects 1.9 million people.

But only about 1.4 million know they have it.

"Arguably, the world has never experienced a health pandemic on this scale before," Professor Greg Johnson, the recently retired chief of Diabetes Australia, said.

"It has been said that if we can't slow this down and prevent people developing diabetes, it threatens to overwhelm our health system."

He said the numbers are growing, and they are "staggering", with type 2 diabetes accounting for 85-to-90 per cent of cases despite being "largely preventable" with the right support.

Type 1 diabetes, which cannot be prevented, accounts for between 10 and 15 per cent of cases, while gestational diabetes is the fastest-growing type of diabetes in Australia.

Diabetes NSW says one-in-four adults aged over 25 are living with diabetes or pre-diabetes.

"We hear a lot about COVID-19 now, as a pandemic," Professor Johnson said. "But we have certainly been saying for a long time that diabetes is the silent pandemic of the 21st century.

"The reason we say it is silent is because it is not as obvious or overt with new case numbers being announced every day. But the numbers for diabetes are absolutely on pandemic proportions."

Type 2 diabetes - which used to be called "adult-onset diabetes" - is increasingly affecting children, adolescents and young adults.

Diabetes Australia is the national body for people affected by all types of diabetes, and those at risk.

Professor Johnson said one of the "big myths" was that diabetes was not as serious as cancer or heart attacks.

"But diabetes is a big killer," he said. "It causes almost 4 million deaths around the world each year, and that's probably an underestimate."

Diabetes contributed to 11 per cent of Australian deaths in 2018, and 1.2 million hospitalisations.

Advocates and medical professionals were concerned COVID-19 outbreaks, restrictions and lockdowns would deter people living with diabetes from seeking health checks and advice for their condition.

But there have been more diagnoses of diabetes in the past year than ever before.

"It has been the biggest increase in the number of people with diabetes ever recorded in Australia, just in the past 12 months, and we don't really know why," Professor Johnson said.

"All we know is that the numbers are higher than they have been in any previous year. We have seen nearly 119,000 new diagnoses of diabetes across Australia in the past 12 months. Previously the highest was about 106,000."

People with diabetes are also at greater risk of serious illness, hospitalisations and intensive care should they be infected with COVID-19.

Prior to the virus consuming our lives and impacting the health system, about 1 in 4 hospitalisations in Australia were related to diabetes.

Professor Johnson said the last definitive published estimate of the effect of type 2 diabetes on the economy was "a few years ago".

"It was $14.6 billion then, but diabetes would now cost the Australian economy closer to $20 billion a year," he said.

Yet we do not have a national type 2 diabetes prevention program. The UK has one. As does the US. But not Australia.

The federal government recently released its latest Australian National Diabetes Strategy for 2021-2030, which conceded that remission of type 2 diabetes in adults could be achieved with dietary interventions such as "stepped food reintroduction" and low carbohydrate diets, as well as bariatric surgery.

"Diabetes is the most common chronic condition that general practice and our primary care system sees, and it has so many flow-on complications in terms of cardiovascular health, contributing to heart attacks and strokes, to kidney failure and dialysis," he said.

"By and large, we underestimate diabetes, and we under-treat it. And it comes back to bite later on. It does lead to premature death in many cases - too many cases - around the world. It is a serious, silent pandemic."

About half of people who develop type 2 diabetes will have already had what is called "pre-diabetes".

But should this population have access to a structured, evidence-based lifestyle program, up to 60 per cent could be prevented from going on to develop type 2 diabetes.

"This is not some magic thing that just happens overnight," he said. "By the time you get type 2 diabetes, for most people, your glucose metabolism has been abnormal for many years already. With pre-diabetes - your glucose metabolism is disrupted but it is not bad enough to be diagnosed with type 2. Not everyone is guaranteed to go on and get diabetes, but all of those people with pre-diabetes are at very high risk of developing type 2.

"The evidence is clear that we can prevent up to 60 per cent of type 2 diabetes in that population with a healthier diet, healthier activity level and a weight reduction generally of around 5 to 7 per cent in body weight."

About two million Australian adults have pre-diabetes.

"Just imagine, if we could identify those two million people tomorrow and, over the next six months, give those 2 million people access to an evidence-based program," he said. "We would see a serious reduction in the number of people developing type 2 diabetes over the next five-to-10 years.

"But we are not doing that at the moment. We are not identifying people with pre-diabetes, and we're not giving them access and encouraging them into prevention programs that are proven to work and help prevent the development of type 2 diabetes."

Professor Johnson said the funding was not there and governments had not come together on a national diabetes prevention program. Small, state-based programs were trying to target the issue.

"But it is just not on a scale that is going to seriously dent the numbers we are seeing," he said. "It is largely preventable to the extent that we have evidence that you can prevent the development of type 2 diabetes, or slow it down for many years, and the most powerful way to do that is through a structured behaviour change program that will address a healthier diet, a healthier activity level and a healthier weight."

A truly national effort by all governments and health services was required.

"What happens at the moment, too often, is that people are told - 'Don't worry too much about it, it's not too serious yet. Just go and watch your diet a bit'," Professor Johnson said. "That is not good enough. That light touch will not achieve anything. We need a systematic approach and people need and should be entitled to know they can access a proven prevention program that might really prevent them from developing type 2 diabetes."