“The number of spermatozoa is declining at an accelerated rate in the world,” write researchers in a study published Tuesday in the scientific journal Update on human reproduction. According to his observations, sperm concentration has halved between 1973 and 2018 and this phenomenon is accelerating. And if sperm count is an “imperfect indicator of fertility,” it is “closely related” to the chances of conceiving, the researchers stress.
To draw these conclusions, the study authors collected data from 223 studies on the subject, from 53 countries (including France) on 6 continents.
A drop of 51.6% since 1973
According to their results, sperm count density fell from 101.2 million per milliliter in 1973 to 49 in 2018. It fell “1.16% per year and 51.6% overall,” the study explains. If this rate may already seem alarming, the study authors also note a “marked increase” in this decline recently: after the 2000s, it’s 2.64% per year.
“Past a threshold of 40 to 50 million/ml, a higher sperm concentration does not necessarily imply a higher probability of conception,” the study read, but “below this threshold, the probability of conception decreases rapidly as which decreases the concentration of spermatozoa. “
This situation is described as “alarming” by the authors, reports The world. “We have a serious problem on our hands that, if left unchecked, could threaten the survival of humanity,” says study co-author Hagai Levine, public health physician and epidemiologist, Hebrew University of Jerusalem.
And in this situation, “France is no exception. In France, thanks to the availability of good quality data, we are sure that there is a strong and lasting drop, as in other parts of the world.”
In fact, the great strength of this study is having established that the decrease in sperm concentration is worldwide. Previous research had established a drop in sperm concentration with data from 1981 to 2013, but they were only talking about men from North America, Europe and Australia, due to a lack of data elsewhere. It also reports lower sperm counts in men in South/Central America, Asia, and Africa.
The causes of infertility
If sperm count is an important parameter to identify a man’s fertility, The Guardian notes, however, that the researchers “did not examine other markers of sperm quality” in their study. On its site, the Medical University of Utah (United States) explains that during a semen analysis, the “percentage of sperm that are motile or capable of swimming” and the shape of the sperm are also studied.
It is difficult to pinpoint the exact cause of this decline in the number of spermatozoa in men, but in recent years several causes have been put forward to explain the decline in fertility in men: the Health Insurance cites tobacco use, obesity, endocrine disruptors but also the many pollutants present in our environment. These factors also affect a woman’s fertility.
For Hagai Levine, the results of the study published this Tuesday are “another sign that something is wrong in the world and that we must do something about it. I think it is a crisis that is better worth facing now, before it reaches its finish”. tipping point that may not be reversible,” she told the guardian.
Source: BFM TV
