Dr. Ryan Riggs sees them almost every day in his fertility clinic at Research Medical Center: Kansas City men struggling with low sperm counts.
Now he knows they’re part of a much larger trend that threatens the population stability of several developed nations, including the United States.
A large-scale study published last week in the journal Human Reproduction Update found that sperm counts declined 59 percent in men from the U.S., Europe, Australia and New Zealand over a 38-year period that ended in 2011. Men in less developed nations in Asia, South America and Africa exhibited no such decline.
“This is amazing,” Riggs said. “I don’t want to be an alarmist but what if, in another 40 years, the numbers are 50 percent lower?”
The birth rate in the U.S. is already at a historic low, and Riggs noted that were it not for immigration, the country would be like some in Western Europe with declining populations and shrinking workforces struggling to support the needs of the elderly.
Riggs called the dropping sperm counts “a societal, macro-epidemiological problem.”
“It has very significant and grave implications,” Riggs said. “It means I’ll have patients in the short term, but in the long term it’s concerning.”
Riggs opened Blue Sky Fertility last October after previously working at a large clinic called Conceptions Reproductive Associates in Colorado.
He said what he has seen personally fits with the results of the much larger study.
“We certainly feel like we see an increasing frequency of gentlemen who have abnormal sperm counts,” Riggs said. “In fact, if you look at the data, in 40 or perhaps even 50 percent of couples, sperm is a factor in their struggle to conceive.”
The study’s authors expressed similar shock and concern at the results, but did not offer any possible explanations for the stark difference between men in the two cohorts.
Riggs pointed to two potential factors driving down sperm counts in developed nations: unhealthy diets and near-constant exposure to chemicals that alter hormone production.
“I personally would look to the endocrine disruptors and obesity as significant factors impacting sperm health,” Riggs said.
While it’s hard to avoid endocrine disruptors such as phthalates, which are in deodorants and perfumes and leach from all kinds of plastic products, Riggs said maintaining a healthy weight — which has long been known to help with fertility — is an important step to take before fertility treatments.
“There are folks who come through my door and I have to advise them, ‘Before we go down this route and potentially spend a lot of money, we need to optimize your health,’” Riggs said.
On a larger level, Riggs said he would be interested in more research to see if there are sperm count differences within different regions in the U.S. and to find out if immigrants’ sperm counts decline after they move to U.S. and how quickly.