In an article published on July 25, 2017 by The Washington Post, reporter Ariana Eunjung Cha informs about a new study that reviewed recent trends in sperm counts. The study was published on the same day in the peer-reviewed journal Human Reproduction Update and conducted by Hagai Levine and colleagues from the Hebrew University Center of Excellence in Agriculture and Environmental Health and the Ben-Gurion University of the Negev, both Israel, as well as the the Icahn School of Medicine at Mount Sinai, U.S., the University of Copenhagen, Denmark, the Federal University of Parana, Brazil, and the University of Murcia School of Medicine and Biomedical Research Institute of Murcia, Spain. The researchers performed a systematic review and meta-regression analysis of 185 English language studies involving 42,935 men who provided semen samples between 1973 and 2011. They extracted 244 estimates of sperm concentration and total sperm count from the studies, as well as information on years of sample collection and covariates such as fertility status, geographic location, age, and ejaculation abstinence time. Levine and colleagues found an overall decline of 52.4% of the mean sperm concentration between 1973 and 2011 among unselected Western men (i.e. men who are not confirmed to be fertile from North America, Europe, Australia, and New Zealand). The mean total sperm count was found to have declined by 59.3% among unselected Western men.
According to Shanna H. Swan, co-author of the study, the analysis “shows the decline is strong and that the decline is continuing.” Factors that can influence sperm count include smoking, stress, obesity, and exposure to endocrine disrupting chemicals (EDCs). Prenatal exposures “can cause permanent damage,” Swan explained, whereas adult exposures “are mostly reversible.” Swan further stated that “having a low sperm count is a signal . . . that there’s something wrong in men’s health overall.”
Ariana Eunjung Cha (July 25, 2017). “Sperm concentration has declined 50 percent in 40 years in three continents.” The Washington Post
EurekAlert! (July 25, 2017). “Comprehensive study shows a significant ongoing decline in sperm counts of Western men.”
Pete Myers (July 26, 2017). “Science: Are we in a male fertility death spiral?” Environmental Health News
Health and Environment Alliance (July 26, 2017). “New Meta-analysis finds that among men from North America, Europe and Australia, sperm concentration has declined more than 50% in less than 40 years.”
Evan Hepler-Smith (July 31, 2017). “How to save your sperm.” The New York Times
Maya Salam (August 16, 2017). “Sperm count in western men has dropped over 50 percent since 1973, paper finds.” The New York Times
Levine, H. et al. (2017). “Temporal trends in sperm count: A systematic review and meta-regression analysis.” Human Reproduction Update (published July 25, 2017).