Sperm concentration among men from Western countries declined by more than 50 percent in less than 40 years. There is a large decrease in sperm quality among men from North America, Europe, Australia, and New Zealand a study reports. The even more disturbing fact is that the decline doesn’t seem to be leveling off. If it continues or possibly even increases among men living in these countries, this will be a major problem for fertility and reproduction.

In 1992, scientists from Denmark claimed that there had been a genuine decline in semen quality over the past 50 years. A study published last week supports that research and doubts of many.  Researchers from the Hebrew University-Hadassah Braun School of Public Health and Community Medicine and the Icahn School of Medicine at Mount Sinai analyzed nearly 200 and screened 7,500 studies on sperm count and quality that were published between 1973 and 2011.

“Decreasing sperm count has been of great concern since it was first reported twenty-five years ago. 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,” said Dr. Shanna H Swan, a professor at the Icahn School of Medicine at Mount Sinai.

Researchers found a 52.5 percent drop in sperm concentration and a 59.3 percent decrease in total sperm count among men who had never had kids and were unaware of their fertility status. No significant decline was seen in South America, Asia and Africa, but the researchers acknowledged that far fewer studies have been conducted on these continents.

“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.

Men who have low sperm count tend to have other health problems as well. Reduced sperm count predicts increased all-cause mortality and morbidity. So far there is no clear evidence for the reason of sperm decrease. There are speculations it’s linked with exposure to chemicals used in pesticides and plastics, obesity, smoking, sedentary lifestyle, stress and diet. The authors speculate it is due to environmental and lifestyle causes but it is a mystery and obstacle yet to overcome.

“If we will not change the ways that we are living and the environment and the chemicals that we are exposed to, I am very worried about what will happen in the future,” said Dr. Levine.

Scientists not involved in the study mostly agree that the paper does represent a step forward in the quality of the data, but further tests will need to be conducted.

Learn more about research from Dr. Levine in the video below:

If you want to know more about lifestyle factors that affect the quality of a man’s sperm, watch the video below:

By Andreja Gregorič, MSc