Scientists FINALLY work out what increases the risk of early-age bowel cancer – shedding a light on the mysterious rise in cases in under 50s
Overweight babies are significantly more likely to go on to develop early age bowel cancer, according to a new study.
The number of under-50s being diagnosed with bowel cancer is on the rise in the UK, but the cause of this increase remains largely a mystery amongst experts.
However, a new study, published by the esteemed Yale School of Public Health, has found that excess weight at birth, along with having an older father, markedly increases the chances of young patients developing the disease.
The finding is significant because studies show there are an increasing number of ‘giant babies’ in the UK.
The condition, known as foetal macrosomia – literally ‘big body’ in Greek – refers to newborns weighing 8lb 13oz or more, and is thought to now affect around one in ten babies in the UK.
Crucially, experts say that macrosomia is typically triggered when the parents are also overweight or have diabetes, meaning the lifestyle choices of parents could doom children to a life-threatening cancer diagnosis.
The findings come four years after the death of Dame Deborah James, also known as Bowel Babe, the journalist and campaigner, who died of the disease at just 40.
Since her death in 2022, the Bowel Babe fund, a charity set up in honour of Dame Deborah and tasked with funding cancer research projects, has raised more than £20 million.
Dame Deborah James, nicknamed the ‘bowel babe’ raised more than £20mn for Cancer Research and is credited for increasing awareness of the disease, which killed her in 2022 aged 40
Every year, around 44,000 people are diagnosed with bowel cancer in the UK. The disease, also known as colorectal cancer, kills around 17,000 over the same time period.
Obesity, lack of exercise and alcohol have all been shown, over time, to raise the risk of the disease.
And, until recently, all research suggested the chances of developing bowel cancer rises with age.
For this reason, the NHS screens those between 50 and 74 for bowel cancer. This involves a biannual at-home poo test, called a faecal immunochemical test (FIT).
However, studies show that, in recent decades, younger patients are increasingly developing the deadly disease.
In Britain, those under 49 today are around 50 per cent more likely to develop bowel cancer than people of the same age in the early 1990s.
For the new study – published in the journal Cancer – researchers matched 1,221 patients who had been diagnosed with bowel cancer before the age of 39 with 61,000 cancer-free controls.
Results showed that men were around a third more likely to develop the disease before the age of 50 than women, consistent with existing trends.
They argue this may be because higher levels of free testosterone – a male sex hormone which drops with age – have been linked to an increased risk of the disease.
But, significantly, the study also found convincing evidence that birth weight has a significant impact on bowel cancer risk.
In females, every half a kilo difference in birth weight was associated with a 10 per cent increased risk. No such association was observed in males.
A similar pattern was observed for paternal age – the age of a man at the time of conception.
The researchers say it’s still unclear why this is the case, but theorise that it could be linked to whether expectant mothers are overweight or have diabetes.
Previous studies have suggested that these conditions can disrupt the production of growth hormones needed during pregnancy, potentially impacting the health of children later in life.
In turn, mothers who are overweight or have diabetes are more likely to have so-called giant babies, according to leading researcher Dr Dimitrios Siassakos, professor of obstetrics at University College London.
Dr Siassakos claims that around one in ten babies in the UK now fall into this category.
Experts say this might explain why larger than average babies are more likely to develop early age bowel cancer – and why the disease is on the rise in this age group.
The Yale study also found that young women whose fathers were 35 or older at the time of conception had a significantly higher risk of early onset bowel cancer.
Older paternal age has been linked to a number of birth defects, including a cleft lip or hole in the diaphragm, with the risk increasing with each year of paternal age.
Some cancers also become more common. Previous studies have found that for every five years older the father is, the risk of a certain type of childhood leukemia increased by 13 per cent.
Separate research has highlighted the increased risk of brain and breast cancers.
Now, experts think there may be a link with early age bowel cancer.
The researchers suggested this may be due to the increase in rate of de novo mutations – genetic changes that arise spontaneously rather than being inherited – among children born to older fathers.
While several theories were highlighted by the study, the researchers acknowledged further studies are needed for validation and that there is unlikely to be one cause behind the ‘mysterious’ rise in early onset cancers.
