Can Climate Change Be Causing Male Infertility?
For many, when we hear the word ‘infertility,’ the first image to pop into our minds is the image of a heartbroken woman. The word infertility has almost become synonymous with women and entire industries have developed around ‘fixing’ the problem. You can find in-person and online support groups for women dealing with infertility and the shame that they can sometimes face from society for being unable to reproduce. But male infertility can play just as much a role in a couple’s inability to conceive as female infertility. Sperm count and sperm health is vitally important when it comes to reproduction. And according to recent studies, both sperm health and count are on the decline. Male infertility is on the rise and it is affecting the world.
In 2017, public health researcher Dr. Hagai Levine released a study in Oxford Academic that was a meta-analysis of male fertility rates, gathered from thousands of reviewed medical studies. The report concluded that sperm concentration had fallen by 52% among men in Western countries between 1973 and 2011. Forty years ago, the average Western man had a sperm concentration of 99 million per milliliter. By 2011, that number had fallen to 47.1 million. This sharp decrease is particularly alarming because sperm concentrations below 40 million per milliliter are considered below normal and can impair fertility. And although this study focused more on Western men simply because there was just more data available on this particular demographic, there are studies showing similar drops in countries like China and Japan as well.
Dr. Levine’s research is considered to be a little on the controversial side simply because consistent and thorough research of male fertility just hasn’t been done over the last several decades. Many people considered infertility only a woman’s problem and dedicated more time and research in understanding female infertility. But Dr. Levine argues that there have been enough researched and reviewed studies over the year to meta-contextualize the trend in sperm concentration and male infertility, while also showcasing the remaining need for more attention in male reproductive health and education. Dr. Levine also argues that we can already see a few of the ripple effects of the lowered sperm count, proving his research argument—all across the globe, birth rates have significantly gone down. Many countries are not producing enough children to replace the existing population. Countries like Japan are in desperate need of children, the government offers financial incentives to couples to have more children. So it can reasonably be assumed, this is a worldwide trend of dropping sperm count and rising male infertility.
So why is this happening? What can be causing this problem?
Well, one possible (and probably most obvious) cause can be physical health. Most men know that they are constantly producing sperm. Unlike women with a set number of eggs, men are able to regularly replenish their sperm reserves. And that may lead some to think that they are invincible when it comes to reproductive health but nothing could be further from the truth. Sperm can be affected very easily by the lifestyle choices a man makes. Smoking, drinking, obesity—they all affect sperm count. Not only do unhealthy lifestyles lower sperm count but they also create poor sperm quality.
A 2013 study of American college students found that men who exercised more than 15 hours a week had sperm counts 73% higher than men who exercised less than five hours a week. And men who watched 20 or more hours of TV a week had much lower sperm counts than those who watched little to no TV. Maintaining an overall healthy lifestyle not only improves and prolongs life but can also help improve sperm count and quality.
Age also plays a factor. The phrase ‘biological clock’ is always thrown at women but men also have a biological clock as well. Beginning around their mid-30s, male fertility begins to degrade. And while men can produce sperm nearly their entire lives, after 40, the sperm quality degrades and there are higher risks of conceiving children with autism or schizophrenia. Many people warn women of conceiving too late as a risk to the child’s health but men are just as culpable of potentially passing down genetic abnormalities.
The environment could also be playing a role in the decrease of sperm count. One proposed theory is the prevalence of toxic, endocrine-disrupting chemical compounds in our everyday lives like bisphenol A, or more commonly known as BPA, and phthalates. These chemicals mimic the effect of the feminizing hormone estrogen and can interfere with hormones like testosterone. These chemicals are found in many plastics and could be affecting and disrupting the delicate nature of the male reproductive system.
A 2011 study found that mice who received daily BPA injections had lower sperm counts and testosterone levels than mice who received saline injections. A study in 2016 found that 60 to 100$ of all the male smallmouth bass studied had eggs growing in their testes, which researchers linked to endocrine disrupters in the waters. Scientists can’t expose humans to endocrine disrupters in an experiment but research has found that similar results can be found in humans who have come in contact with endocrine disrupting chemicals.
The argument that environment is causing the plunge in sperm count could even be taken to a more macro level. Climate change might even be a factor for the global lowering of sperm concentration. Heat plays a role in sperm life. High temperatures can kill sperm which is why the testicles are outside the body, keeping them up to 5.4 degrees cooler. Researchers have found that birth rates tend to decline nine months after a heat wave. This has led some experts to believe that climate change may be contributing to the sperm count decline.
And of course, stress can play a significant role in sperm health and count. Sperm counts across the world dropped steeply after the 2008 economic crash. But even after years of the economy slowly climbing back up, sperm concentrations has yet to catch up. Stress and uncertainty can tax the body physically and can lower sperm count. Stress also can manifest itself in unhealthy physical habits such as possibly eating or drinking too much, linking both environmental and physical causes for lowered sperm count.
So what can be done about all of this? It’s overwhelming and perhaps a little defeating to hear so many possible ways to lower or degrade sperm count and quality. The medical community as a whole would be better suited to address these issues if more research was dedicated to male fertility. There are 1/3 the number of urologists in the U.S. than there are OB-GYNs, with most men not even realizing urologists are the specialists they would consult or any concerns regarding male reproductive health. Having more research and funding geared towards understanding and treating male infertility can help not only men but couples everywhere understand how they might be able to finally conceive.
Education for the general male population is crucial as well. Conceiving a child takes two people and it isn’t solely the woman’s responsibility to worry and maintain her reproductive health. Men should educate themselves on the equally large role they play in a couple’s fertility and take the necessary steps in maintaining a healthy reproductive system.
But on a more, every day, practical level, what can we do to address this problem of lowering sperm concentration? Firstly, go to the doctor. Get a check up. Find out first what exactly is happening and if there are any signs a doctor can immediately pinpoint for male fertility issues. Then make healthy lifestyle choices (diet, exercise, moderation in drinking and smoking), add supplements if necessary, and discuss with your partner what steps you can make together to improve your fertility.
It is understandable why so many men disregard their reproductive health. For so long, the idea of fertility has been associated only with women. But the sooner men and medical science realize the importance in further studying male fertility, the better it will be for everyone. Currently, infertile men have very few resources or support groups to turn to. We need to make a change so that men can not only gain more knowledge in how their bodies work but become better, more educated advocates for their reproductive health.
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Hagai Levine, Niels Jørgensen, Anderson Martino-Andrade, Jaime Mendiola, Dan Weksler-Derri, Irina Mindlis, Rachel Pinotti, Shanna H Swan, Temporal trends in sperm count: a systematic review and meta-regression analysis, Human Reproduction Update, Volume 23, Issue 6, November-December 2017, Pages 646–659, https://doi.org/10.1093/humupd/dmx022
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