Dwindling Sperm Counts Have Impacts Beyond Male Fertility

In 2017, in the midst of media buzz about the Hulu infertility parable Handmaid’s Tale, life imitated art. Scientists announced in Human Reproduction Update that sperm counts in Western nations had dropped over the past 40 years by more than 50 percent. The trend, they said, is likely to continue — which is an especially problematic prognosis in light of new research revealing that low sperm counts mean more than just infertility.

Speaking on Sunday at ENDO 2018, the Endocrine Society’s 100th annual meeting in Chicago, Illinois, endocrinologists from Italy explained their observations in a new study on the link between semen quality, reproductive function, and metabolic risk.

“Infertile men are likely to have important co-existing health problems or risk factors that can impair quality of life and shorten their lives,” said lead investigator Alberto Ferlin, M.D., Ph.D. of the University of Padova, who is also president of the Italian Society of Andrology and Sexual Medicine, in a statement released Monday. “Our study clearly shows that low sperm count by itself is associated with metabolic alterations, cardiovascular risk and low bone mass,” he continued.

Ferlin collaborated with Dr. Carlo Foresta at the University of Padova in the study, in which the team hypothesized “low” sperm counts in men — less than 39 million per ejaculate, a broadly accepted standard — would be linked to other health problems outside of infertility. In their study on 5,177 male partners of Italian infertile couples, their hunch was confirmed.

The men with low sperm counts were 1.2 times more likely to have more body fat, higher blood pressure, less “good” cholesterol, and more “bad” cholesterol. These men were also more likely to have “metabolic syndrome,” a cluster of conditions (high blood pressure, high blood sugar, excess body fat around the waist, and abnormal levels of cholesterol or triglycerides) that predispose a person to diabetes, heart disease, and stroke.

Compounding the increased risk of developing diabetes, the men with low sperm counts also had higher insulin resistance, a condition in which the body doesn’t respond properly to insulin, leading to type 2 diabetes and prediabetes. Their risk of having low testosterone levels was increased 12-fold compared to peers with normal sperm counts, and half the men with low testosterone were at risk for osteoporosis.

Offering a silver lining, the researchers said that knowing the health risks associated with male infertility will allow doctors to improve, more generally, the health of men who have low sperm counts. “Men of couples having difficulties achieving pregnancy should be correctly diagnosed and followed up by their fertility specialists and primary care doctor because they could have an increased chance of morbidity and mortality,” Ferlin said.

What still remains a mystery, however, is why sperm counts are dropping among men in North America, Europe, Australia, and New Zealand in the first place. One possibility is that it’s an environmental issue, as the researchers who conducted the Human Reproduction Update research didn’t see such a dramatic drop in sperm count in Asia, Africa, or South America. But previous research has shown that exposure to pesticides and other chemicals, as well as smoking and obesity, can hurt sperm counts, too. Calling sperm count the “canary in the coal mine,” the researchers behind that study, led by Dr. Hagai Levine of Hadassah-Hebrew University, warned men to consider their health more generally, for the sake of the entire human race.

“I am a big fan of the TV adaption of The Handmaid’s Tale, as well as Margaret Atwood’s books,” Levine told Inverse in a previous interview, referring to the show’s central theme of global infertility. “Personally, I believe these fears are valid.”