It is a disabling gut condition that can cause crippling pain and excruciating digestive problems – and it is becoming increasingly common among young Americans.
Crohn’s disease causes the immune system to attack the digestive tract, leaving sufferers battling bouts of diarrhea, stomach pain and exhaustion that can last for years.
Over time, the damage can become even more serious, raising the risk of colorectal cancer.
And there is growing concern about how many young people are developing the disease.
Around one million Americans now live with Crohn’s. One major study found rates among under-20s rose 22 percent in less than a decade, while cases among under-40s have also surged globally.
Scientists are still trying to understand why.
But experts told the Daily Mail that clues are emerging – and some point towards everyday features of modern life, from the food we eat to medicines commonly taken in childhood.
So what is driving the rise in Crohn’s, just how is this linked to the worrying, much-talked-about rise in colon cancer in younger Americans, and is there anything you can do to reduce your risk?
Crohn’s is a disabling gut condition that can cause crippling pain and excruciating digestive problems – and it is becoming increasingly common among young Americans
Why Crohn’s most often strikes young people
Crohn’s can strike at any age, but it most often emerges relatively early in life – with an estimated 70 percent of cases diagnosed before age 40.
Dr Sameer Berry, a gastroenterologist at NYU Langone Health, says there may be a number of reasons for this.
One is that our 20s and 30s are a period of significant change – not just inside our bodies, but in the way we live.
‘You leave home, you may start smoking, you may change your diet. Many people start antibiotics for certain things,’ he told the Daily Mail.
‘There’s a lot of changes that happen in that period when you’re becoming a young adult and you start making your own decisions.’
All of these factors can affect the gut microbiome, the vast community of bacteria living in our digestive system, and its relationship with the immune system.
Dr Berry said this relationship is particularly important in early adulthood, when disruption to the balance of bacteria in the gut may make the immune system more likely to mistakenly attack healthy tissue, triggering the inflammation seen in Crohn’s.
There is also a smaller peak in Crohn’s later in life, at around age 60.
Dr Berry said this may be linked to the opposite process: as the immune system ages, changes in the way it functions can make chronic inflammation more likely.
The colon cancer link
Crohn’s doesn’t just cause debilitating digestive symptoms – it can also significantly increase the risk of colorectal cancer.
People with inflammatory bowel disease (IBD) affecting the colon are around one-and-a-half to two times more likely to develop the cancer than the general population, with the greatest danger among those who have suffered years of widespread, uncontrolled inflammation.
That is particularly concerning given that colorectal cancer itself is rising sharply among younger Americans.
Rates among under-50s increased from 8.6 cases per 100,000 people in 1992 to 13 per 100,000 in 2018, and have been climbing by around two percent a year since 2004.
But Dr Berry cautions against assuming the two trends are directly connected.
Most colorectal cancers begin as polyps – small growths in the bowel that can slowly turn cancerous over a period of around a decade.
In Crohn’s patients, cancer can develop differently. Years of inflammation can repeatedly damage cells lining the colon, eventually causing changes that can turn them cancerous.
‘In Crohn’s disease, it’s chronic inflammation across the entire lining that causes DNA damage, and then cancer arises from that inflammation,’ Dr Berry said.
Yet there is an encouraging twist.
Despite Crohn’s becoming more common, research suggests the once-alarming rates of colorectal cancer seen among people with IBD have fallen over recent decades.
Experts believe better treatment may be one reason. Modern drugs can suppress the damaging inflammation that drives cancer risk, while regular colonoscopies allow doctors to spot and remove suspicious changes before they become dangerous.
Studies have found that IBD patients who undergo regular colonoscopies are less likely to develop colorectal cancer and, if cancer is found, are less likely to die from it.
That makes controlling the disease particularly important.
‘The number one thing you can do is make sure your Crohn’s disease is under control because if you have active inflammation, you’re going to have higher risk of future cancer,’ Dr Berry told the Daily Mail.
For most healthy Americans, colorectal cancer screening begins at age 45, with a colonoscopy generally recommended every ten years.
But Crohn’s patients can require much closer monitoring. Dr Berry recommends some undergo a colonoscopy every one to three years – even if they have no warning signs of cancer.
Why genetics don’t tell the whole story
Crohn’s can run in families – sometimes striking several members across generations.
Around ten to 15 percent of patients have an immediate family member with the disease, while having a parent with Crohn’s can dramatically increase a person’s risk.
Studies of identical twins provide some of the strongest evidence for a genetic link: if one twin develops Crohn’s, the other is substantially more likely to develop it too.
‘Family history is a very strong risk factor,’ Dr Berry said. ‘But they are not 100 percent of the story.’
In fact, there is no single ‘Crohn’s gene.’ Researchers have identified scores of genetic differences that appear to make some people more susceptible to the disease, but none guarantees they will develop it.
And genetics alone cannot readily explain why Crohn’s has become more common over a matter of decades.
Our genes simply do not change that quickly.
Instead, experts increasingly believe Crohn’s develops when an underlying genetic vulnerability collides with something in a person’s environment.
‘It can’t only be genetic,’ Dr Berry told the Daily Mail. ‘We know it’s environmental.’
And researchers are beginning to identify some of the everyday exposures that may help tip the balance.
How smoking could cause Crohn’s disease
Comedian Peter Davidson, pictured above, has shared that he was diagnosed with Crohn’s disease at age 17
Smoking is one of the clearest avoidable risk factors for Crohn’s.
One large study of more than 200,000 women found smokers had roughly double the risk of developing the disease compared with those who had never smoked.
Cigarette smoke is thought to damage the protective mucus lining of the intestines, alter the bacteria living in the gut and reduce blood flow needed to repair damage.
‘It’s a very strong risk factor, and it’s a modifiable one,’ Dr Berry said.
And the danger continues after diagnosis. Smokers with Crohn’s are more likely to suffer complications and see their disease return after surgery.
‘It can worsen your disease course once you’re diagnosed,’ he added.
The growing threat of ultra-processed food
Scientists are also increasingly interested in another feature of modern life: ultra-processed food.
A BMJ study of more than 116,000 people found those eating five or more servings a day had an 82 percent higher risk of developing IBD than those eating less than one.
Intriguingly, minimally processed red meat and dairy were not associated with increased risk.
‘It’s the processing that increases the risk,’ Dr Berry said.
One suspect is emulsifiers – additives used to improve the texture of foods such as ice cream, sauces and salad dressings – which may damage the gut’s protective mucus layer.
The 2025 ADDapt Trial out of King’s College London found Crohn’s patients who cut down on emulsifiers experienced less inflammation and were more likely to go into remission.
Could antibiotics play a role?
Antibiotics are another possible piece of the puzzle – particularly when they are taken early in life.
The first few years are when the community of bacteria living in the gut becomes established. Antibiotics can disrupt that process by killing beneficial bacteria alongside those causing infections.
One Danish study found children exposed to antibiotics early in life had around a 40 percent higher risk of subsequently developing IBD.
Additionally, a 2026 review found that antibiotic use in childhood was associated with a higher chance of Crohn’s disease specifically.
But Dr Berry stressed that antibiotics remain essential when children have bacterial infections.
‘It’s about making sure we’re only giving them when needed,’ he said.
Role of toxic ‘forever chemicals’ and microplastics
A growing body of evidence suggests microplastics and ‘forever chemicals’ may be linked to increased Crohn’s risk
Dr Sameer Berry told the Daily Mail that focusing on modifiable risk factors such as smoking and diet may reduce Crohn’s risk
Scientists are also investigating whether PFAS ‘forever chemicals’ and microplastics could play a role – but here the evidence is far less convincing.
Studies have found links between exposure to the pollutants and signs of intestinal inflammation, while people with IBD have been found to have more microplastics in their stool.
Other research shows that higher blood levels of microplastics before a Crohn’s diagnosis were associated with an increased risk of developing the condition a decade later.
But none of this proves the substances cause Crohn’s, said Dr Berry.
‘This is an area where the evidence is very thin,’ he added.
He expects more answers as research develops, but said it could be years before scientists know whether these ubiquitous pollutants genuinely increase the risk.
Can you prevent Crohn’s disease?
There is no guaranteed way to prevent Crohn’s.
But Dr Berry said the evidence suggests people may be able to reduce their risk by not smoking, eating plenty of fruit and vegetables, limiting ultra-processed food and avoiding unnecessary antibiotics.
Regular exercise may also help, while studies suggest people who were breastfed as babies have a lower risk of developing the disease.
Most important is recognizing Crohn’s early, before years of uncontrolled inflammation cause lasting damage.
Warning signs include persistent abdominal pain and diarrhea, blood in the stool and unexplained weight loss.
‘If we can catch it early, then we can treat it early,’ Dr Berry said, ‘and we can reduce the downstream effects of the inflammation.’
