While most discussions about fertility largely center on women’s health, a new comprehensive study shows that male reproductive health should be included in the conversation as well. The findings suggest sperm counts may have declined, particularly in Western countries, by as much as 50 percent over 40 years — but researchers aren’t really sure why.
For the study, which was published in the journal Human Reproduction Update, an international team of researchers analyzed 185 studies involving 43,000 men across the world between 1973 and 2011. The team found a 52.4 percent decrease in sperm concentration — and a 59.3 percent decline in overall sperm count — in men from North America, Australia, New Zealand, and Europe. However, no significant decline was observed in men from South America, Asia, and Africa, although researchers noted that there have been far fewer studies conducted in those regions.
This analysis certainly isn’t the first time researchers have looked at the topic of male fertility. As the Washington Post reports, several past studies found that sperm counts and quality have been declining. But the previous research was mostly dismissed or criticized, due to limitations like changing laboratory methods or failing to take into account whether the participants already had known infertility issues. For the current study, however, the researchers made it a point to address those concerns. They still found that sperm counts were declining, which could point to serious health risks for men.
“Decreasing sperm count has been of great concern since it was first reported 25 years ago,” study author Shanna H. Swan of Icahn School of Medicine at Mount Sinai in New York, said in a statement. “This definitive study shows, for the first time, that this decline is strong and continuing. The fact that the decline is seen in Western countries strongly suggests that chemicals in commerce are playing a causal role in this trend.”
The study authors noted that further research is needed to determine the cause for the decline in sperm count — and that low sperm count could represent a larger problem of poorer health in men. “The results are quite shocking,” study co-author Hagai Levine of the Hebrew University of Jerusalem told The Guardian. “This is a classic under-the-radar huge public-health problem that is neglected.”