Men with severely reduced fertility appear to have a higher risk of developing colorectal and thyroid cancers.
Previous research has also linked lower male fertility to a range of health issues, including diabetes, cardiovascular disease, metabolic disorders, testicular and prostate cancer and early death.
“Reproductive capacity is linked to an individual’s genetic makeup,” the lead researcher said. “One theory is that if something goes wrong at the genetic level—which can manifest as reduced sperm quality—other systems in the body may also be affected, increasing the risk of disease.”
In a study published in the European Journal of Epidemiology, researchers analysed data from more than 1.1 million Swedish men who had their first child between 1994 and 2014.
They compared cancer rates in 14,540 men who conceived using ICSI (a type of assisted reproductive technology) with those who became fathers naturally.
Men who used ICSI were nearly twice as likely to develop colorectal cancer and about three times as likely to develop thyroid cancer.
However, the researchers stress that while the relative risk is higher in men with poor sperm quality, the overall risk remains low at the population level, and fertility treatment itself is not considered to cause cancer.
The findings suggest that men seeking help for fertility problems may benefit from earlier screening and preventive health care measures.
