Too many New Zealanders under 40 think their health is "bullet-proof".
That's the opinion of health insurance giant nib CEO Rob Hennin who says in reality they are leaving their health to chance.
He says health studies showing some chronic diseases like bowel cancer are affecting more young and middle-aged people is proof serious illness can hit people at any age.
Most New Zealanders have no health insurance. A 2015 Ministry of Health survey reveals the proportion of adults with health cover has shrunk from 40 per cent in 1997 to 35 per cent in 2015; in the same period coverage for children has dropped from 31 per cent to 28 per cent.
Hennin says people who don't take responsibility for their wellbeing, or at least take health insurance cover, risk playing roulette with their health.
"They are certainly taking chances but why take those chances if you don't have to?" he says. "Young people like to think they're bullet-proof but the reality is illness can strike at any age."
Health research here and overseas is showing chronic disease is no longer the preserve of the elderly.
In the US the National Cancer Institute says millennials - those born between 1980 and 1995 - are four times more likely to develop bowel cancer than baby boomers born around 1950.
This trend is being mirrored in New Zealand. A recent University of Otago study found the cancer has increased significantly in people under 55 in the last 20 years - up by 13 per cent among women and 18 per cent in men.
It is not just bowel cancer. Worldwide up to 15 per cent of all strokes occur in people under 50 and a recent international study published in the UK medical journal The Lancet found a startling 25 per cent increase in the number of stroke cases among people aged 20 to 64 in the last 20 years - this at a time when the overall numbers dying from strokes is dropping.
In New Zealand the Stroke Foundation says a quarter of all strokes occur in people under 65 including children, 40 of whom suffer a stroke each year.
Almost 27,000 New Zealanders under 40 have diabetes according to Ministry of Health statistics. This is about 10 per cent of the total of 260,000 - a figure which has doubled in 10 years.
Other Ministry of Health figures show 30 per cent of the 3,000 women diagnosed with breast cancer every year are under 50.
In Australia a 2015 National Health Survey found there were 12,000 people between 18 and 40 with coronary heart disease and a further 12,000 with other forms of heart disease - an illness which is New Zealand's biggest killer accounting for a third of all deaths every year.
The World Health Organisation says noncommunicable diseases of these kinds are occurring globally in epidemic proportions citing smoking, alcohol, lack of exercise and poor nutrition as primary risk factors.
Hennin encourages people to treat their health as an asset, and take responsibility to exercise, eat well and get good sleep.
"At nib we exist to help people fund their health and believe this is as important as keeping fit and eating well," he says. "Those in the 20 to 40 age-group (they account for 20 per cent of claims received by nib) are the future of our country, and probably have less financial flexibility than older people.
"So a relatively modest weekly outgoing on a health insurance premium is a sensible investment," he says.
Hennin says while the public health system offers a good service, it doesn't always give people what they want when they want it (110,000 are on waiting lists while another 170,000 needing elective surgery have not even made it to a waiting list).
"In the private system a heart operation can cost anything up to $70,000, hip and knee replacements up to $25,000 and I don't think many people have that sort of money available," he says.
"People say all the time they want to be fit so they can play with their kids and grandkids - let alone keep working. But if you're on a waiting list for a knee or hip operation you can't continue to do these things."
Hennin says health insurance isn't just for those who are sick and nib believes prevention is better than cure: "We encourage people to use their health insurance to have regular check-ups which may lead to early detection of ill health. This way they can seek treatment before it's too late."
One who did this was Auckland woman Jacinda Nisbet. Diagnosed with breast cancer on her left side 16 years ago she was stunned when the cancer re-appeared on her right side last year.
"I just didn't ever imagine in my wildest dreams I would have been diagnosed again, so it was a real shock, a real shock the second time," she says.
Nisbet is recuperating well after quickly arranging through her nib insurance operations for a mastectomy and breast reconstruction.
"I don't really want to look back, I'm going to keep moving and enjoy life," she says. "The premium we pay will never cover what they gave us, that's probably the most important part. I'd recommend insurance to anybody."