A recent study suggests a significant link between the age of a father at conception and the risk of his daughters developing bowel cancer. The research, published in the journal CANCER, found that women whose fathers were 35 or older when they were born had a 56% higher risk of being diagnosed with early-onset colorectal cancer (EOCRC) by age 40, compared to those born to fathers aged 20 to 24.
Early-onset colorectal cancer, diagnosed before age 50, is becoming more prevalent in younger adults. In the UK, over 2,400 individuals under 50 are diagnosed annually, marking a 25% increase in cases among younger adults over the last decade. While lifestyle and dietary changes have been suspected drivers, this study highlights paternal age as a potential influencing factor.
The Yale University-led research team analyzed over 1,200 cases of bowel cancer in individuals under 40 and compared them with more than 61,000 healthy individuals. The study noted that sons of fathers over 35 showed only a 7% higher risk, a figure deemed not statistically significant.
Scientists propose that genetic mutations linked to older paternal age could explain the heightened risk. Previous research has associated advanced paternal age with complications such as stillbirth, cleft palate, acute lymphoblastic leukemia, and retinoblastoma.
However, the study's authors caution that their findings are observational and do not definitively prove causation, only an association. Further research is needed to fully understand the underlying mechanisms.
Beyond paternal age, the study identified other factors associated with an increased risk of early-onset colorectal cancer. For women, every 500g increase in birth weight correlated with a 10% greater risk of developing the disease. Overall, men were found to be 34% more likely than women to develop bowel cancer before age 40. Additionally, Hispanic individuals faced a 43% higher risk compared to non-Hispanic white individuals, while those with foreign-born mothers had a 15% lower risk.
Sunny Siddique, the study's lead author from Yale School of Public Health, emphasized the importance of examining demographic, birth, and parental characteristics to understand the rising incidence of EOCRC. He called for future studies to investigate how factors like sex, ethnicity, birth weight, maternal birthplace, and paternal age influence this risk.
The findings emerge amid growing global concerns about the rise of bowel cancer in young adults. Similar trends have been observed in countries including Australia and Canada. Experts stress that while research continues, over half of bowel cancer cases are preventable through lifestyle choices such as a healthy diet, maintaining a healthy weight, regular exercise, and limiting alcohol and smoking. Symptoms to be aware of include changes in bowel habits, blood in stool, unexplained weight loss, fatigue, and abdominal pain.