Men with reduced fertility are relatively unlikely to develop Prostate cancer, Swedish investigators report.

“Men who are childless have an almost 20 percent lower risk of getting Prostate cancer than those who have fathered two or more children,” Dr. Aleksander Giwercman of Malmo University Hospital in Sweden told. Men with one child, he added, have a risk in between that of these two groups.

Giwercman and colleagues note in the International Journal of Cancer that male hormones - androgens - are thought to play a key role in the development of Prostate cancer, as well as levels of fertility.

The researchers used the Swedish national cancer registry to look into any association between male fertility and the risk of Prostate cancer. The study, which involved 48,850 men with prostate cancer and an equal number of healthy controls, revealed such a link.

“However, among childless men there are probably three categories,” Giwercman pointed out. “Those who are truly infertile/subfertile and have impaired testicular function; those who have a subfertile/infertile partner but have normal testicular function; and those who remained single or do not wish to have children.”

It’s logical to assume that “the association between childlessness and Prostate cancer risk is mainly due to the first group of men.”

Men with impaired testicular function not only produce less sperm but also produce less testosterone, on average, he explained. “We believe that our study provides indirect evidence of an association between testosterone production in young adulthood and subsequent Prostate cancer risk, with those having subnormal testosterone production having a lower risk of getting prostate cancer.”

SOURCE: International Journal of Cancer, July 20, 2005.