Sperm concentration has decreased by 52.4% in men from North America, Europe, Australia and New Zealand, and in recent years the trend has shown no signs of stabilization. And all this has happened in just 40 years.
The study has been published in the magazine Human Reproduction Update and it has been carried out by screening 7,500 studies and conducting a meta-regression analysis in 185 studies.
The Hadassah Braun School of Public Health and Community Medicine of the Hebrew University and the Icahn School of Medicine of Mount Sinai has conducted this study that has analyzed sperm concentration trends in Western men between 1973 and 2011.
Despite the amazing decline in Western men, this decline was not observed in men from South America, Asia and Africa, where the amount of studies has been lower.
Although this investigation does not assess the causes of the decrease observedThis count is probably associated with environmental factors and lifestyles, including prenatal exposure to chemicals, and that of adults to pesticides, smoking, stress and obesity.
As he explains Hagai Levine, lead author and head of the Environmental Health Area of the Hadassa Braun School of Public Health and Community Medicine, of the Faculty of Medicine of the Hebrew University of Jerusalem:
Given the importance of sperm concentration for male fertility and human health, this study is an urgent call for researchers and health authorities around the world to investigate the causes of this steep decline, in order to prevent .
As well Jaime Mendiola, one of the authors of the work and researcher in the Public Health and Epidemiology group of the University of Murcia (UMU):
The decrease in sperm concentration has been known since 1992, but the issue remains controversial due to the limitations of previous studies. However, this new study has a broader scope and uses rigorous meta-regression methods, which allows to adequately address the reliability of the estimates of the studies, and can also take into account other factors that could explain this decrease, such as age, withdrawal time, and the selection of the study population.