Nov 16, 2022 13:00:00

It turns out that men's 'sperm count' has been halved worldwide in the past 40 years and the pace of decline is accelerating in the 21st century

Male

sperm is essential for humans to make children, but in recent years it is known that the number of sperm contained in semen is decreasing. A new meta -analysis that integrates and analyzes semen data collected from 1973 to 2018 in 53 countries around the world revealed that the number of sperm in men worldwide has been halved over the past 40 years.

Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries | Human Reproduction Update | Oxford Academic
https://doi.org/10.1093/humupd/dmac035

Sperm count is declining at accelerating rate worldwide: study
https://www.france24.com/en/live-news/20221115-sperm-count-is-declining-at-accelerating-rate-worldwide-study

In 2017, a research team led by Hagai Levine , a public health doctor at the Hebrew University of Israel, found that the concentration of semen in men living in North America, Europe, Australia, and New Zealand had decreased significantly over the past 40 years. published research results. The study analyzed data from 185 studies collected between 1973 and 2011, but data from countries in South America, Central America, Asia, and Africa were scarce, suggesting similar trends in these regions. I couldn't presume there was.

Researchers show that ``the possibility of human extinction'' is shown by a decrease in sperm count - GIGAZINE

Therefore, Levine conducted a comprehensive review of the papers published between 2014 and 2019, extracted those containing data on male sperm count, and combined them with data used in previous studies to create a new meta. performed an analysis.

A total of 288 data used in this meta-analysis were based on semen samples provided by 57,168 men between 1973 and 2018. Of all the data, 199 were collected from men in North America, Europe, and Australia, and 89 were collected from men in South America, Central America, Asia, and Africa.

As a result of analysis, the number of sperm in men who are not infertile has decreased by more than 51% from 101.2 million to 49 million per milliliter of semen between 1973 and 2018, and the annual pace of decline is about . turned out to be 1.1%. The research team also reports that the pace of global sperm count decline has accelerated in the 21st century.

In addition, overseas media AFP communication points out that not only the number of sperm affects fertility, but also the motility of sperm is a factor that affects fertility. In addition, the figure of 49 million per milliliter of semen exceeds the lower reference value of 16 million per milliliter of semen that the World Health Organization (WHO) considers 'normal'.

Sarah Martins da Silva, a fertility specialist at the University of Dundee in Scotland, who was not involved in the study, said the rate of decline in men's sperm counts has been shown to have doubled since 2000. , pointed out that the reason for this is not clear. 'It has been suggested that lifestyle factors such as pollutants, plastics, smoking, drugs, obesity and poor diet are contributing factors, but their impact is poorly understood and vaguely defined,' he said. increase.

On the other hand, Alan Pacey , a professor of andrology at the University of Sheffield in England, who was also not involved in the study, praised the study as ``a very elegant meta-analysis,'' but said the quality of the old data may be low. indicates concern that there is In response to this concern, Da Silva argued, 'It will be difficult to ignore numbers and consistent results.'