The analysis, carried out by Professor Hagai Levine of the Hebrew University of Jerusalem and Professor Shanna Swan at the Icahn School of Medicine in New York, found that the average global sperm count more than halved between 1973 and 2018. Since 1972 it had declined by about 1 percent each year, the researchers said. However, since 2000, the annual decline has averaged more than 2.6 percent. Levine said the findings served as “a canary in a coal mine.” “We have a serious problem on our hands that, if not mitigated, could threaten the survival of humanity,” he said. The paper, published in the journal Human Reproduction Update on Tuesday, was based on data from 53 countries and included statistics collected from the previous study. It focused on sperm count trends among men in South America, Asia and Africa – regions not examined in the previous report. Men in these regions shared the significant decline in total sperm count and sperm concentration previously observed in North America, Europe and Australia, the researchers said. Levine said: “Overall, we are seeing a significant global decline in sperm count of more than 50 percent over the past 46 years, a decline that has accelerated in recent years.” Although the study did not examine the causes of these declines, Levine pointed to recent research showing that disruptions in reproductive tract development in utero were associated with “lifetime fertility impairment and other markers of reproductive dysfunction.” It called for global action “to promote healthier environments for all species and reduce exposures and behaviors that threaten our reproductive health.” Swann said the accelerating decline in global sperm counts means “more people will need to use assisted reproduction to conceive”. The consequences went beyond reduced fertility, as lower sperm counts “were associated with more diseases later in life — cardiovascular disease, diabetes and reproductive cancers — and shorter life expectancy.” The decline was too rapid to be due to genetic causes alone, he argued, noting that some risk factors for lower sperm counts had to do with lifestyle factors such as diet, smoking, obesity, stress and excessive alcohol consumption. However, he emphasized the role of environmental chemicals, particularly those that have the ability to affect steroid hormones, which are critical to reproduction. The most significant were “endocrine disruptors” chemicals that could alter testosterone and estrogen levels, such as phthalates – found in hundreds of cleaning and personal care products – and bisphenols (BPA) which are often part of the containers that used to store food and drinks such as water bottles. These were “critically involved in reproductive function,” Swan added. He urged men to avoid “smoking, a sedentary lifestyle, excessive weight gain, drug and alcohol abuse, and potentially toxic chemicals.”
