Infertility affects nearly 7.3 million couples in the United States. The male partner is either the sole cause or contributing cause of infertility in around 40 percent of cases, according to the American Society for Reproductive Medicine. A number of contributing factors to male infertility includes decreased sperm production or function, genetic defects, diabetes, enlarged veins in the testes, and cryptorchidism or undescended testicles. 

A new study from the Stanford University School of Medicine in California, published in the journal Human Reproduction, suggests that men who are infertile because of defects in their semen appear to be at increased risk of dying earlier than men with normal functioning semen.

The research team analyzed 11,935 medical records from men aged between 20 years and 50 years who visited either Stanford Hospital & Clinics between 1994 and 2011, or the Baylor College of Medicine in Houston between 1989 and 2009, for semen quality, such as motility and shape of the semen and total semen volume and sperm counts. 

The investigators were able to monitor the men’s mortality for an average of eight years by analyzing data from the National Death Index and the Social Security Death Index. “We were able to determine with better than 90 percent accuracy who died during that follow-up time," Dr. Michael Eisenberg of Stanford University School of Medicine in California said. "There was an inverse relationship. In the years following their evaluation, men with poor semen quality had more than double the mortality rate of those who didn't.”

Though a single semen abnormality could not predict mortality, men with two or more semen abnormalities had more than double the risk of death over the eight-year period following their initial fertility examination compared with those with no semen abnormalities. According to the study, the greater the number of abnormalities, the higher the mortality rate.

Of the almost 11,935 men studied, 69 died during the follow-up period. The researchers admit that this is a small number, but they say it reflects the patients’ “relative youth”, since subjects were an average age of 36.6 years. They noted that the men who get evaluated for infertility tend to have above average socioeconomic status and have healthier diets, education, and access to health care.

Lastly, the researchers indicated that men who are concerned about infertility are men who want to have children.

“If you're trying to have a child, you're probably reasonably healthy at the moment and in mental shape to be planning for your future,” Eisenberg said. In fact, the men evaluated by the two medical centers — both those with and those without semen abnormalities — died at slower rates than the general United States male population.

Regardless, the team believes their results demonstrating that men with two or more semen defects have increased mortality risk is “statistically significant”.

It is reasonable to think that the increased mortality risk may be caused by these health problems, rather than infertility itself, since the infertility could have been caused by any medical conditions the men may already have.

“But we controlled for this factor as best we could,” says Dr. Eisenberg, “and while that did attenuate the measured risk somewhat, there seems to be something else going on.”

“Could it be genetic, developmental or hormonal factors? Or could it be that something about the experience of having and raising kids - even though you may sometimes feel like they're killing you - actually lowers mortality?” 

Additional Reference:

Male infertility linked to mortality in study led by Stanford researcher