A study published in the journal Human Reproduction Update, based on 153 assessments from men who may have been unaware of their fertility, suggests that average sperm concentration dropped from about 101.2 m per ml to 49.0 m per ml between 1973 and 2018 – a drop of 51.6%. Total sperm count dropped by 62.3% over the same period. Research by the same group, reported in 2017, found that sperm concentration had more than halved over the past 40 years. However, at the time, a lack of data for other parts of the world meant that the findings were concentrated in an area that included Europe, North America and Australia. The latest study includes more recent data from 53 countries. Decreases in sperm concentration were observed not only in the previously studied region, but in Central and South America, Africa and Asia. What’s more, the rate of decline appears to be increasing: looking at data collected across all continents since 1972, the researchers found that sperm concentrations were declining by 1.16% per year. However, when they only looked at data collected from the year 2000, the decline was 2.64% per year. “I think this is another message that something is wrong with the world and we need to do something about it. So yes, I think it’s a crisis, that we [had] better addressed now, before it reaches a tipping point that may not be reversible,” said Professor Hagai Levine, first author of the study from the Hebrew University of Jerusalem. Previous studies have shown that fertility is compromised if sperm concentration falls below about 40 m per ml. While the most recent estimate is above that threshold, Levine noted that this is an average number, suggesting that the percentage of men below that threshold will have increased. “Such a decline clearly represents a decline in the reproductive capacity of the population,” he said. While the study took into account factors such as age and how long the men had gone without ejaculating, and excluded men known to have infertility, it has limitations, including that it did not look at other markers of sperm quality. Alan Pacey, a professor of andrology at the University of Sheffield, who was not involved in the work, praised the analysis but said he remains on the fence about whether there is a drop-off. “Sperm counting, even with its gold standard technique [the laboratory process] hemocytometry, it’s really difficult,” he said. “I think over time we’ve just gotten better at it because of the development of training and quality control programs around the world. I still think that’s a big part of what we’re seeing in the data.” However, Levine dismissed such concerns, adding that, in any case, the decline has been sharper in recent years. Although it is unclear what may be behind the apparent trend, one hypothesis is that endocrine-disrupting chemicals or other environmental factors may play a role by acting on the fetus in utero. Experts say factors such as smoking, drinking, obesity and poor diet can also play a role, and that a healthy lifestyle can help boost sperm count. Tina Kold Jensen of the University of Southern Denmark said the new study highlights a worrying trend. “You keep finding the same trend no matter how many studies you include — that’s a little scary to me,” he said. Professor Richard Sharpe, an expert in male reproductive health at the University of Edinburgh, said the new data showed the trend appeared to be a global phenomenon. Sharp said the decline may mean it takes longer for couples to conceive and, for many, time is not on their side, delaying trying to conceive until the woman is in her 30s or 40s. when her fertility is already reduced. “The key point to make is that this is desperately bad news for couples’ fertility,” he said. But, Sharpe said, “These issues are not just a problem for couples trying to have children. They are also a huge problem for society over the next 50 years, as fewer and fewer young people will be around to work and support the growing population of the elderly.”
title: “Humans Could Face Reproductive Crisis As Sperm Count Declines Study Suggests Fertility Problems " ShowToc: true date: “2022-11-23” author: “Alicia Knowles”
A study published in the journal Human Reproduction Update, based on 153 assessments from men who may have been unaware of their fertility, suggests that average sperm concentration dropped from about 101.2 m per ml to 49.0 m per ml between 1973 and 2018 – a drop of 51.6%. Total sperm count dropped by 62.3% over the same period. Research by the same group, reported in 2017, found that sperm concentration had more than halved over the past 40 years. However, at the time, a lack of data for other parts of the world meant that the findings were concentrated in an area that included Europe, North America and Australia. The latest study includes more recent data from 53 countries. Decreases in sperm concentration were observed not only in the previously studied region, but in Central and South America, Africa and Asia. What’s more, the rate of decline appears to be increasing: looking at data collected across all continents since 1972, the researchers found that sperm concentrations were declining by 1.16% per year. However, when they only looked at data collected from the year 2000, the decline was 2.64% per year. “I think this is another message that something is wrong with the world and we need to do something about it. So yes, I think it’s a crisis, that we [had] better addressed now, before it reaches a tipping point that may not be reversible,” said Professor Hagai Levine, first author of the study from the Hebrew University of Jerusalem. Previous studies have shown that fertility is compromised if sperm concentration falls below about 40 m per ml. While the most recent estimate is above that threshold, Levine noted that this is an average number, suggesting that the percentage of men below that threshold will have increased. “Such a decline clearly represents a decline in the reproductive capacity of the population,” he said. While the study took into account factors such as age and how long the men had gone without ejaculating, and excluded men known to suffer from infertility, it has limitations, including that it did not look at other markers of sperm quality. Alan Pacey, a professor of andrology at the University of Sheffield, who was not involved in the work, praised the analysis but said he remained on the fence about whether there is a drop-off. “Sperm counting, even with its gold standard technique [the laboratory process] hemocytometry, it’s really difficult,” he said. “I think over time we’ve just gotten better at it because of the development of training and quality control programs around the world. I still think that’s a big part of what we’re seeing in the data.” However, Levine dismissed such concerns, adding that, in any case, the decline has been sharper in recent years. Although it is unclear what may be behind the apparent trend, one hypothesis is that endocrine-disrupting chemicals or other environmental factors may play a role by acting on the fetus in utero. Experts say factors such as smoking, drinking, obesity and poor diet can also play a role, and that a healthy lifestyle can help boost sperm count. Tina Kold Jensen of the University of Southern Denmark said the new study highlights a worrying trend. “You keep finding the same trend no matter how many studies you include — that’s a little scary to me,” he said. Professor Richard Sharpe, an expert in male reproductive health at the University of Edinburgh, said the new data showed the trend appeared to be a global phenomenon. Sharp said the decline may mean it takes longer for couples to conceive and, for many, time is not on their side, delaying trying to conceive until the woman is in her 30s or 40s. when her fertility is already reduced. “The key point to make is that this is desperately bad news for couples’ fertility,” he said. But, Sharpe said, “These issues are not just a problem for couples trying to have children. They are also a huge problem for society over the next 50 years, as fewer and fewer young people will be around to work and support the growing population of the elderly.”
