A newly published study in the Journal of Human Reproduction has some alarming news about sperm count in four industrial nations: North America, Europe, Australia and New Zealand. No decline of significance was seen in South America, Asia or Africa, although, as the researchers point out, not many studies of this kind have been conducted in those areas.
Researchers at the Hebrew University-Hadassah Braun School of Public Health and Community Medicine in Jerusalem analyzed data from 7,500 studies on men who did not undergo treatment for infertility between 1973 and 2011, totaling nearly 43,000 men.
They divided the studies into two fertility-defined groups: men “unselected by fertility status,” meaning they were unlikely to be aware of their fertility but were screened via military service or other tests; and fertile men, those known to have helped conceive a pregnancy.
The data showed sperm concentrations declined from 99 million per milliliter to 47.1 million per milliliter during the span of the study, which translates to a 52.4% decline in sperm concentration and a 59.3% decline in total sperm count for the men studied. Though this decline is significant, it’s still in fertile range, well above the 15 million that qualifies as infertile.
The study authors claim declining sperm count is “of considerable public health importance” for a number of reasons. First, and most obvious, sperm count is an indicator of male fertility, and one of the key components of semen analysis. Considering that of the approximately 15% of Americans with fertility problems, 50% of these problems are related to male fertility issues, this also has an economic effect for heterosexual couples who invest in fertility treatments to conceive a child. Second, the authors explain, reduced sperm count is a predictor of mortality, and is associated with testicular disorders and testicular cancer. Lastly, sperm count and other semen parameters have been linked to environmental influences, including endocrine disrupting chemicals, pesticides, heat, noise and lifestyle factors, including diet.
“This study is an urgent wake-up call for researchers and health authorities around the world to investigate the causes of the sharp ongoing drop in sperm count,” said co-lead author, Hagai Levine, an epidemiologist, public health physician and faculty member of the Braun School of Public Health and Community Medicine.
Responses in the sexual medicine community have ranged from crying impending apocalypse to shrugging off the results as insufficient.
Dr. Paul Gittens, Director of the Centers for Sexual Medicine in Philadelphia and New York finds himself in the middle, neither outright panicked but definitely paying attention, though he admits “this data has sent shockwaves through our fertility world.” He points out that a similar paper was published in the 1970s that showed sperm counts had decreased “and there was this big sperm apocalypse, but then things settled down and we continued to reproduce.”
Gittens points out that there are a number of reasons—hormonal, genetic and environmental—for lowered sperm counts. “Which of these factors has caused the decline at this point is a mystery, but it could also be a combination of them.”
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