Findings from a new systematic review indicate that there has been a significant decline in sperm concentration and total sperm count among Western men since 1973.

The analysis was conducted by researchers from the Hebrew University-Hadassah Braun School of Public Health and Community Medicine and the Icahn School of Medicine at Mount Sinai using a total of 185 studies which included 42,935 semen samples provided between 1973 and 2011. Overall, between 1973 and 2011 the decline amounted to 52.4% (−1.38; −2.02 to −0.74; P<0.001) in sperm concentration. An even greater overall decline (59.3%) was seen in total sperm count. No significant decline was noted in South America, Asia and Africa, however there were far less studies conducted for these men. 

“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,” said Dr. Shanna H Swan, a co-author of the study. 

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The study did not investigate the causes of sperm concentration and total sperm count decline. However, previous literature has reported on the wider implications of fertility and reproductive decline. 

“Given the importance of sperm counts for male fertility and human health, 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, with the goal of prevention,” said Dr. Hagai Levine, the lead author and Head of the Environmental Health Track at the Hebrew University-Hadassah Braun School of Public Health and Community Medicine, in the Hebrew University of Jerusalem’s Faculty of Medicine. 

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