Children born before their father reaches his mid-30s have a significantly lower risk of developing early-onset colorectal cancer before age 50 than other children, according to a new study.
A research team from Yale University's School of Public Health analyzed data from 1,221 people diagnosed with colorectal cancer before age 50 in California between 1988 and 2021, along with a control group of 61,050 people, according to the British health and medical outlet Medical Xpress.
The study found that people whose fathers were under 35 at the time of their birth had a 56% lower risk of early colorectal cancer than those whose fathers were 35 or older.
Sex, race, and birth weight were also associated with the risk of developing early colorectal cancer. Men's risk was 34% higher than women's, and Hispanic people's risk was 43% higher than that of white people. For women, the analysis showed that the risk of early colorectal cancer increased by 10% for every 500-gram increase in birth weight. On the other hand, when the mother was born in a country other than the United States, the child's risk of early colorectal cancer was 15% lower.
The research team stressed that follow-up studies are needed to determine how birth environment and parental factors influence the recent rapid increase in colorectal cancer patients among younger people.
The rising number of colorectal cancer patients among younger people has recently emerged as a major challenge in the global public health community. Until now, post-adulthood lifestyle habits such as processed food consumption, obesity, and sedentary living have been pointed to as the main causes.
This study is notable for expanding the examination of early colorectal cancer risk factors beyond adult lifestyle habits to include the prenatal environment and parents' biological conditions.
In particular, it drew attention for examining how a father's age relates to a child's future cancer risk. Generally, the effects of older parenthood on children have been discussed mainly in terms of the mother's age.
The findings suggest that genetic changes or DNA methylation changes that occur as a father's sperm cells age may affect a child's adult health. However, this study analyzed associations, and it is difficult to interpret it as meaning that a father's age is a direct cause of early colorectal cancer.
The proportional relationship between birth weight and early colorectal cancer risk, confirmed only in girls, is also noteworthy. It has been suggested that excessive nutritional supply in the intrauterine environment or exposure to certain hormones may affect the metabolic system or the proliferation process of colon mucosal cells after growth.
This shows that not only obesity management in childhood and adolescence but also weight and nutrition management during pregnancy may be important for long-term health.
Biological factors such as differences in sex hormones or the gut microbial environment may have influenced men's higher risk of developing early colorectal cancer. The higher risk among Hispanic people and the lower risk among children with foreign-born mothers also support the idea that environmental factors, such as dietary changes and lifestyle differences between immigrant generations, may be involved in colon health.
This study shows that the increase in colorectal cancer among younger people is difficult to explain solely by current diet or lifestyle. Researchers point out that studies are needed to determine how environmental and biological factors in the early stages of life, and even before birth, affect early colorectal cancer risk.
The findings were published in the international academic journal Cancer.
