Women whose fathers were 35 or older when they were born may face a notably increased risk of developing bowel cancer as adults, new research suggests.
The study found that daughters of men aged at least 35 at the time of their birth had a 56 per cent greater chance of being diagnosed with the disease by age 40 than those whose fathers were between 20 and 24 when they were born.
Bowel cancer diagnosed before the age of 50, formally known as early-onset colorectal cancer (EOCRC), has become increasingly common in Britain, mirroring a broader rise in several cancers among younger adults.
In the UK, more than 2,400 people under 50 are diagnosed with bowel cancer each year, and cases in younger adults have climbed by 25 per cent over the past 10 years.
Experts have long pointed to shifts in diet, lifestyle and other modern environmental factors as possible contributors to the troubling increase.
However, the researchers behind the latest study, published in the medical journal CANCER, said the findings indicate that “paternal age may influence risk of early onset colorectal cancer”.
Led by a team at Yale University, the researchers examined more than 1,200 bowel cancer cases diagnosed before age 40 — a younger threshold than the usual under-50 definition used for EOCRC — and compared them with more than 61,000 people who did not have the disease.
The increased risk was far more pronounced among daughters. Sons born to fathers over 35 showed only a 7 per cent higher risk, a difference the researchers said was “not statistically significant”.
Daughters of men who became fathers after the age of 35 could be at a significantly higher risk of developing bowel cancer in adulthood, a study suggests
The team believe a possible explanation for their findings is that previous studies have found older fathers have been linked to genetic mutations in their children.
They cited previous research linking greater paternal age to complications including stillbirth. They also said there have also been links to children being born with an opening in the roof of the mouth – known as a cleft palate – as well as acute lymphoblastic leukaemia, which is a fast-growing blood and bone marrow cancer, and retinoblastoma, a rare eye cancer.
Scientists believe this may help explain the higher bowel cancer risk found in the new study, though they urged caution and stressed that further research is required.
As the study was observational, it also cannot prove that becoming a father later in life causes bowel cancer – only that there is a link between the two in their research.
Beyond a father’s age, the study found a wider range of factors linked to a higher risk of developing the cancer beyond a father’s age, including birth weight.
Researchers uncovered that, for every 500g increase in weight at the point of birth, women were at a 10 per cent greater risk of developing bowel cancer.
The study also found that men were 34 per cent more likely than women overall to develop the disease before 40.
Meanwhile, Hispanic people were at a 43 per cent higher risk of developing the disease than non-Hispanic white people, while those with foreign-born mothers had a 15 per cent lower risk.
Sunny Siddique, the study’s lead author from Yale School of Public Health, said: ‘Evaluating demographic, birth, and parental characteristics is important in understanding what’s causing the rising incidence of early-onset colorectal cancer.
‘Our findings warrant future studies aimed to understand the mechanisms through which factors such as male sex, Hispanic ethnicity, birthweight, maternal birthplace, and paternal age may influence risk of early onset colorectal cancer.’
The findings come amid growing concerns about the rise in bowel cancer among young adults.
Dawson’s Creek star James Van Der Beek tragically died after a two-year battle with the disease in February, aged just 48.
Dawson’s Creek star James Van Der Beek died after a two-year battle with bowel cancer aged just 48
Analyses last year uncovered that bowel cancer cases are on the rise in under 50s across nations including Britain, Australia and Canada.
Dr Ahmedin Jemal, senior vice president of surveillance, prevention and health services research at the ACS, said previously: ‘It’s clear that colorectal cancer can no longer be called an old person’s disease.
‘We must double down on research to pinpoint what is driving this tsunami of cancer in generations born since 1950.’
Around 44,000 cases of bowel cancer are diagnosed every year in the UK, with about 130,000 in the US.
The disease kills almost 17,000 Britons each year – making it the nation’s second-most common cause of cancer death behind lung cancer – with the death toll rising to about 50,000 in America.
Overall, just over half of bowel cancer patients are expected to be alive 10 years after their diagnosis.
Cancer Research UK estimates that more than half – 54 per cent – of bowel cancer cases are preventable.
Experts say incorporating a healthy diet, reducing body weight, exercising more, and cutting back on alcohol and smoking are all lifestyle choices that can reduce risk.
Symptoms of the disease can include changes in bowel habits, such as looser stools, unusual diarrhoea or constipation.
Needing to use the toilet more often, finding red or black blood in the stool, or bleeding from the back passage are also warning signs.
Other possible symptoms include stomach pain, bloating, a lump in the stomach, unexplained weight loss, fatigue, or shortness of breath – signs that may indicate anaemia caused by bowel cancer.
