A recent study suggests that being born heavier and having an older father are significant factors that increase the risk of developing bowel cancer at an early age. The research, published in the journal Cancer by the Yale School of Public Health, aims to shed light on the mysterious rise in colorectal cancer diagnoses among individuals under 50.
In the UK, the number of people under 50 being diagnosed with bowel cancer has been increasing. The study found that excess weight at birth, a condition known as foetal macrosomia where newborns weigh 8 pounds 13 ounces or more, is associated with a higher likelihood of developing the disease. This condition is thought to affect about one in ten babies in the UK and is often triggered when parents are overweight or have diabetes.
Researchers matched 1,221 patients diagnosed with bowel cancer before age 39 with over 61,000 cancer-free individuals. The findings indicated that men were about a third more likely to develop bowel cancer before 50 than women. While the exact reasons are still being investigated, one theory suggests higher levels of free testosterone in men may play a role.
The study also highlighted a significant impact of birth weight on bowel cancer risk, particularly in females. For every half-kilogram difference in birth weight, there was a 10% increased risk observed in females. No similar association was found in males.
A similar pattern was observed concerning paternal age, the age of the father at the time of conception. Young women whose fathers were 35 or older at conception had a significantly higher risk of early-onset bowel cancer. Older paternal age has previously been linked to an increased risk of various birth defects and certain childhood cancers.
Researchers hypothesize that these links might be due to an increased rate of de novo mutations, genetic changes that occur spontaneously, in children born to older fathers. Additionally, the study suggests that parental factors leading to macrosomia, such as maternal overweight or diabetes during pregnancy, could disrupt growth hormone production and affect a child's health later in life.
Bowel cancer, also known as colorectal cancer, affects around 44,000 people in the UK annually, with approximately 17,000 deaths. While factors like obesity, lack of exercise, and alcohol consumption are known risk factors, and the disease typically rises with age, recent decades have seen a marked increase in younger patients. In Britain, individuals under 49 today are about 50% more likely to develop bowel cancer compared to those of the same age in the early 1990s.
The findings come four years after the death of journalist and campaigner Dame Deborah James, who died of bowel cancer at age 40. The Bowel Babe fund, established in her honor, has raised over £20 million for cancer research projects.