Colon cancers may be surging in under 50s because some young people’s bodies are ageing faster than they should be, experts have discovered in a first-of-its-kind study.
Researchers at the University of Miami have found the phenomenon — dubbed accelerated ageing — may increase the risk of developing the disease.
Accelerated ageing is said to have occurred when a person’s biological age is greater than their actual — or chronological — age.
While chronological age refers to years lived, biological age is based on physiological markers that reflect the impact of genetics, lifestyle choices and environmental factors on the body.
It can be determined through sophisticated DNA analysis saliva or blood tests.
If a person is 50, but their biological age is 55, their ageing has accelerated by five years, said Dr Shria Kumar, a colorectal cancer specialist behind the new research.
‘That might be reflected in overall body functioning,’ she added.
‘It sounds pretty theoretical, but actually accelerated aging has been shown to be predictive of time to death and even of multiple cancers.
Colorectal cancer rates in people under 50, called early-onset colorectal cancer, are on the rise.
The finding comes amid a worldwide explosion of colon cancers in younger patients that has baffled doctors.
While it is most common in over-50s, the disease has surged by 50 per cent in the younger age-groups over the past three decades, recent data suggests.
For this reason in the US, health chiefs now recommended colon cancer screening — also known as bowel cancer screening — starts at 45.
Some doctors now say this needs to be moved even younger, because half of early-onset colorectal cancers occur in people under 45, according to the latest statistics from the National Cancer Institute.
In the UK, NHS screening is only available to those aged 54 to 74.
Perhaps the most recognisable victim of the trend is Deborah James — known as 'bowel babe' — who was diagnosed at just 35 and raised millions for charity in her final days in 2022, before she died aged 40.
James spoke of her rigorous exercise routine, and being in the best shape of her life when she developed the illness.
If a person is 50, but their biological age is 55, their ageing has accelerated by five years, said Dr Shria Kumar, a colorectal cancer specialist behind the new research
The exact reason for the link between accelerated ageing and colon cancer isn't fully understood.
However, some factors that raise a person's risk of early-onset colorectal cancer also elevate biological age.
These include poor diets — including diets high in ultra-processed foods — obesity, smoking, alcohol consumption and other lifestyle habits.
Other key factors in accelerated ageing are pollution and stress.
Earlier this year, separate research found young people diagnosed with certain types of cancer – especially lung, gastrointestinal and uterine cancers – were more likely to suffer accelerated ageing.
Intriguingly, the US researchers involved in the study said there was 'strong evidence' that the risk of accelerated ageing, and therefore of developing cancer, increased with each successive generation born after 1965.
And that may mean Gen Z – those born between 1997 and 2012 who are becoming young adults today – are at a far greater risk of developing potentially deadly diseases such as cancer at a much earlier stage than their parents or grandparents.
Professor Ilaria Bellantuono, co-director of the Healthy Lifespan Institute at the University of Sheffield, told : 'We don't know enough to say for certain that younger generations are ageing faster or why,' she says.
'That research hasn't been done. But it's not impossible. We are seeing more disease in younger people, the kinds of diseases we might normally expect to be developing in older adults.
'And biological ageing is a risk factor for those diseases. In the same way that smokers increase their risk of lung cancer, does accelerated ageing increase the risk of developing more multiple long-term chronic conditions?'
Dr Kumar suggested that testing for accelerated ageing could help flag up younger individuals who need to be offered regular screening and colonoscopies.
Colon cancer screening comes in the form of convenient stool-sample tests carried out at home.
It is offered as early detection of the disease has been shown to improve both treatment options and outcomes for this disease.
A positive screening test result is typically followed by a colonoscopy, during which any polyps found can be removed.
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'It sounds pretty theoretical, but accelerated aging has been shown to be predictive of time to death and even of multiple cancers,' Dr Kumar continued.
'What's really exciting about the opportunity in colorectal cancer is that we have a clear prevention tactic.
'Colonoscopy is not only early detection, but also cancer prevention.'
Consultant oncologist Dr Hendrik-Tobias Arkenau, from HCA Healthcare in London, said the colon cancers in young people are most frequently only being spotted in their later, or sometimes tragically, final stages.
‘Who thinks a 35 or 42-year-old has bowel cancer if they have tummy ache, weight loss, some blood (in stool),’ he said.
Dr Arkenau said he believes the reason behind the increase to be unclear, although he thought it was a combination of factors influencing the microbiome of young people's guts.
He said use of antibiotics in childhood, falling rates of breastfeeding, vitamin intake and diet changes are just some factors that could be at play.
‘There is no clear cut one thing, I think it is multi-factorial and there are other aspects,’ he said.
Analysis suggests deaths from colon cancer overall in the UK are set to rise by 2,500 a year between now and 2040.
Meanwhile, the number of people in the UK diagnosed with the disease will rise by around a tenth in the same period.
Bowel cancer currently kills just shy of 17,000 Brits each year with only half of those diagnosed expected to survive 10 years after learning they have the disease.