7 ms·

This comes up every now and then, and I take a look at some research and it always seems pretty clear that it's obesity. edit: the phthalates comes up every ti

This comes up every now and then, and I take a look at some research and it always seems pretty clear that it's obesity. edit: the phthalates comes up every time. Yeah it does seem to have some effect, but the effect sizes found in papers doesn't seem to be that huge, meanwhile the effect size of obesity is very large, and the prevalence of it is observably growing rapidly. You also have to consider that the people with the most bioaccumulant shit like this are the people with large reserves of fatty tissue to absorb it.

vnjxk 5y ago
I always thought it was the rise of porn
- uuddlrlr 5y ago
  Why would that increase infertility?
  - macksd 5y ago
    None of these things is infertility directly, but they might be what the parent comment is thinking of. I hear of links between ejaculation and prostate health a lot, but that's usually a positive relationship. Sex therapists that I read do seem to universally deny any link between moderate to excessive masturbation and impotence. There are correlations between ED and the rise of Internet porn usage, but that also correlates with the availability of medicines to treat ED and thus the marketing of a solution to a problem.
  - blix 5y ago
    From a purely observation perspective, pornography consumption has increased dramatically at the same time as falling fertility. Even if a mechanism isn't obvious, it at least seems like there is a possibility of a connection. Studies have indicated that long-term pornography use correlates with erectile dysfunction and loss of interest in sexual relationships. It's not hard to imagine that fertility might be related to these other aspects of reproductive health. Unfortunately few long-term studies seem to focus on fertility specifically. Short term studies on the influence of porn find that novel sexual stimulus seems to increase sperm quality while it attenuates in response to repeated exposure to the same stimulus. This is bad news for real life humans who cannot change as rapidly or dramatically as one can switch videos.
  - wsc981 5y ago
    > Why would that increase infertility? Indeed ... wasn't it supposed to cause blindness?
  - elzbardico 5y ago
    The lower cost of sexual release in porn leading to less motivation to pursue relationships with the opposite sex, an activity which in our current state of reproductive preferences, moral values and technology is strongly correlated with instances of human reproduction.
- slothtrop 5y ago
  you're thinking of ED
- bobthechef 5y ago
  That's ED. P.S. The use of "fertility" to describe men is weird and seems recent. Fertility is passive and receptive and thus better fits women (hence the use in agriculture to describe the earth). Virility is a better term because it is active. Some people seem to falsely claim that it doesn't refer to procreative or generative power, but it does as this entry in Etymology Online[0] shows (emphasis mine): "period of manhood," 1580s, from French virilité, from Latin virilitatem (nominative virilitas) "manhood," from virilis "of a man, manly, worthy of a man," from vir "a man, a hero," from PIE root wi-ro- "man." Meaning "power of procreation, capacity for sexua[l] intercourse" is from 1590s; sense of "manly strength" is recorded from c. 1600. There's not much power to procreate if you have a low sperm count. [0] https://www.etymonline.com/word/virility#etymonline_v_30873 https://www.etymonline.com/word/virility#etymonline_v_30873
  - orwin 5y ago
    I think "lack of fertility" to design low sperm count/inviable spermatozoids is accurate. Lack of virility would be impossibility to use your own penis for different reasons. 10-8 year ago i knew a trans who was fertile and could give sperm to her lesbian friends, but lacked virility. The female counterpart of virility should be femininity. DNA and knowledge of the specific of procreation is probably as recent as the use of fertility. Wanted to comment about obesity but i guess most people said what i wanted to say, so i'm rebounding on a tangent for my own self-esteem, sorry.
  - elzbardico 5y ago
    Technically you're right. But If I was a researcher, I would stay clear of using a term that could be understood as some kind of endorsement of toxic masculinity, heteronormativity or whatever. Better to use the slightly less accurate term, overloading its original meaning with a new one, and avoid being the subject of a witch hunt.
elil17 5y ago
An interesting series of articles that came up on HN a couple months ago makes the argument that both infertility and obesity arise from environmental contaminates (although not necessarily phthalates). Regardless of whether you agree with the arguments presented, I think it’s really interesting to see just how complex of a problem it is to figure out what’s going on. https://slimemoldtimemold.com/2021/07/07/a-chemical-hunger-part-i-mysteries/ https://slimemoldtimemold.com/2021/07/07/a-chemical-hunger-p...
- spywaregorilla 5y ago
  I don't particularly buy it. Again, sure, maybe it has a statistically significant effect, but it is undoubtedly dwarfed by people chugging sugary drinks and being more sedentary. A casual search suggests sugar consumption has increased 9 fold since the 1800s and 2 fold since the 1900s. The poor in particular are cornered into purchasing sugary foods due to weird economics around corn subsidies. And what do you know? They're the fattest by far. If it were mostly environmental you'd see broader gains. variation. But in my little bubble in upper middle class Massachusetts, I don't know ANYONE who is obese. In other areas of the country it's hard to find anyone who isn't.
  - atom_arranger 5y ago
    The linked site does suggest a reason Massachusetts would have less overweight people, based on their exposure to environmental contaminants.
    - spywaregorilla 5y ago
      Sure. But you'll find plenty of fat people in poorer areas of massachusetts.
  - orwin 5y ago
    Maize fructose has probably a bigger effect than cane sugar, because it also hit poor populations.
- marcosdumay 5y ago
wyager 5y ago
There is probably some bidirectional causality between decreasing T levels and rising obesity.
- eloff 5y ago
  I think that's pretty firmly established. It's also a leading cause of ED.
  - hnuser123456 5y ago
    So is circumcision.
    - eloff 5y ago
      That's the opposite of firmly established. I say that as no fan of the practice.
      - copperx 5y ago
        It took me a few seconds to realize your comment was a pun.
JohnWhigham 5y ago
BPA/BPB in plastics is another source. Unfortunately, this one is basically unavoidable since even if one doesn't own any of those plastics at home, there's bound to be some food product that uses a plastic container. Even more so, we don't know anything about how long it takes to leach into the food, what plastics do/don't contain it, stuff like that. Plastics should just be banned from touching food entirely.
- pvarangot 5y ago
  I think it really depends on the food. Like processed or skinned meat absorbs more than seeds or dry food, frozen absorbs less, or something like that. I haven't read about it for a while but that's what I remember was kind of like the consensus about where to start looking into if it's feasible to ban BPA.
- pxeboot 5y ago
  If you have running water in your home, every drop likely flows through hundreds of feet to miles of plastic pipe before you drink it. Even if you have a private well and copper plumbing, your pump and other components almost always contain plastic parts that make contact with the water.
rich_sasha 5y ago
I thought I remember reading it is dropping across the line, including for fit and healthy individuals. Is that not right, and if it is, what could that mean? Sorry for lack of source, it’s not my area.
- spywaregorilla 5y ago
  I can recall only one article that was posted here which included that, but I came away thinking it was misleading. It binned weight categories(e.g. BMI ranges from X-Y) and showed that over time, people were falling into heavier categories, and that sperm outcomes were getting worse in every category (heavily in the obese, less so in the normal weight range). But if you eyeballed the curve it felt very likely that the distribution of individuals was just shifting the the heavier end within each category. E.g. if a healthy BMI is 18-25, and you look at the the average outcome for that group over time... if the whole population gets fatter then the mean value in the 18-25 group could shift from 20 to 22. So... take it as you will. Sorry for no source here either.
giantg2 5y ago
It seems like a combination of issues. The obesity thing tends to hold across many other species too. I would guess you are right about this being the main driver. A classic example would be dealing with animal husbandry and obese pigs. Fertility in obese females can be impacted too. A variety of toxins have been shown to cause fertility issues too, such as lead and pesticides. It's also possible that estrogen and estrogen mimicking compounds found in drinking water could fall into this category (estrogen can adversely affect male fertility). Testoterone is also a factor which has seen a large decline over the last 50 years. Obesity and sedentary lifestyle can cause a decline in testorerone and other hormones/enzymes related to sperm. Then there's a possible link to RF reducing sperm quality. Although I think this is probably a secondary factor that might exacerbate the others.
- jxramos 5y ago
  That's an interesting idea, but I'm not sure the anatomy lines up. Like the mass of belly fat and fatty liver pressing down from above in upright humans resting on the pudendal artery wouldn't be the same as how the mass hangs on quadrupeds. This is an interesting line of thought too, like what organs get compressed under gravity from increased mass assuming it's primarily a mechanical problem.
  - giantg2 5y ago
    I'm not talking about anatomy, but rather physiology (obesity affects hormones related to sperm). Do you have some information to suggest this is an anatomical issue (other than sleep apnea) rather than physiological one?
    - jxramos 5y ago
      nothing specific other than speculating about hearing about stuff around that bottom part of the body: lower sperm count, slower bowel movements with constipation and stuff. I wonder if there's anything else anatomical down there that could potentially get disrupted from extra mass bearing down on it.
newaccount2021 5y ago
If it truly is obesity at work, then the research will be buried. There are too many obese people...they could elect a President if they wanted. You can't offend them. The CDC director refuses to finger-wag at the US public even though there is a solid correlation between obesity and covid outcomes. Why can't we say this? No politician is willing to tick off the obese, that's why.
omgwtfbyobbq 5y ago
Do you have any links? Offhand I would suspect exercise, but I guess that's hard to differentiate from obesity.
- spywaregorilla 5y ago
  Studies correlating obesity and poor sperm quality are numerous and easy to find. https://www.hsph.harvard.edu/news/hsph-in-the-news/excess-weight-sperm-fertility/ https://www.hsph.harvard.edu/news/hsph-in-the-news/excess-we... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3521747/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3521747/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5657098/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5657098/ You can find more without much effort. What I don't see are epidemiological studies trying to track the prevalence of obesity vs. the average sperm quality across different nations. Unfortunately.
betwixthewires 5y ago
Or perhaps the correlation between obesity and low fertility is not causation, obesity could very well be a symptom of whatever is causing it, alongside low fertility.
- spywaregorilla 5y ago
  Obesity is fairly well documented to cause poor fertility in animal studies
supperburg 5y ago
People who eat meat and animal fat and cut out sugar report getting pregnant after years of not being able to. They also report iso-caloric weight loss, resolution of diabetes 2, thickening of hair and many other positive health heuristics. Obesity, diabetes and metabolic considerations are an absolute powder-keg of medical progress just waiting for mainstream acceptance
- watwut 5y ago
  The people getting pregnant after eating meat are unlikely to be men.
poorjohnmacafee 5y ago
If obesity it perhaps should be studied as a realtime pushback against modern diets by nature/natural selection, in reducing unhealthy people from the gene pool.
- spywaregorilla 5y ago
  Obese people are not intrinsically unhealthy. They're usually just unable to access reasonable nutrition.
  - poorjohnmacafee 5y ago
    Risks for cardiovascular disease, stroke, cancer, and of course diabetes, are all significantly increased with obesity. Risk of getting severe covid-19 is significant increased with obesity. I know plenty of relatively wealthy people who are fat or even skinny fat (arguably worse condition), it's not only about access to reasonable nutrition.

vnjxk 5y ago

I always thought it was the rise of porn

uuddlrlr 5y ago
Why would that increase infertility?
- macksd 5y ago
  None of these things is infertility directly, but they might be what the parent comment is thinking of. I hear of links between ejaculation and prostate health a lot, but that's usually a positive relationship. Sex therapists that I read do seem to universally deny any link between moderate to excessive masturbation and impotence. There are correlations between ED and the rise of Internet porn usage, but that also correlates with the availability of medicines to treat ED and thus the marketing of a solution to a problem.
- blix 5y ago
  From a purely observation perspective, pornography consumption has increased dramatically at the same time as falling fertility. Even if a mechanism isn't obvious, it at least seems like there is a possibility of a connection. Studies have indicated that long-term pornography use correlates with erectile dysfunction and loss of interest in sexual relationships. It's not hard to imagine that fertility might be related to these other aspects of reproductive health. Unfortunately few long-term studies seem to focus on fertility specifically. Short term studies on the influence of porn find that novel sexual stimulus seems to increase sperm quality while it attenuates in response to repeated exposure to the same stimulus. This is bad news for real life humans who cannot change as rapidly or dramatically as one can switch videos.
- wsc981 5y ago
  > Why would that increase infertility? Indeed ... wasn't it supposed to cause blindness?
- elzbardico 5y ago
  The lower cost of sexual release in porn leading to less motivation to pursue relationships with the opposite sex, an activity which in our current state of reproductive preferences, moral values and technology is strongly correlated with instances of human reproduction.
slothtrop 5y ago
you're thinking of ED
bobthechef 5y ago
That's ED. P.S. The use of "fertility" to describe men is weird and seems recent. Fertility is passive and receptive and thus better fits women (hence the use in agriculture to describe the earth). Virility is a better term because it is active. Some people seem to falsely claim that it doesn't refer to procreative or generative power, but it does as this entry in Etymology Online[0] shows (emphasis mine): "period of manhood," 1580s, from French virilité, from Latin virilitatem (nominative virilitas) "manhood," from virilis "of a man, manly, worthy of a man," from vir "a man, a hero," from PIE root wi-ro- "man." Meaning "power of procreation, capacity for sexua[l] intercourse" is from 1590s; sense of "manly strength" is recorded from c. 1600. There's not much power to procreate if you have a low sperm count. [0] https://www.etymonline.com/word/virility#etymonline_v_30873 https://www.etymonline.com/word/virility#etymonline_v_30873
- orwin 5y ago
  I think "lack of fertility" to design low sperm count/inviable spermatozoids is accurate. Lack of virility would be impossibility to use your own penis for different reasons. 10-8 year ago i knew a trans who was fertile and could give sperm to her lesbian friends, but lacked virility. The female counterpart of virility should be femininity. DNA and knowledge of the specific of procreation is probably as recent as the use of fertility. Wanted to comment about obesity but i guess most people said what i wanted to say, so i'm rebounding on a tangent for my own self-esteem, sorry.
- elzbardico 5y ago
  Technically you're right. But If I was a researcher, I would stay clear of using a term that could be understood as some kind of endorsement of toxic masculinity, heteronormativity or whatever. Better to use the slightly less accurate term, overloading its original meaning with a new one, and avoid being the subject of a witch hunt.

elil17 5y ago

An interesting series of articles that came up on HN a couple months ago makes the argument that both infertility and obesity arise from environmental contaminates (although not necessarily phthalates). Regardless of whether you agree with the arguments presented, I think it’s really interesting to see just how complex of a problem it is to figure out what’s going on. https://slimemoldtimemold.com/2021/07/07/a-chemical-hunger-part-i-mysteries/ https://slimemoldtimemold.com/2021/07/07/a-chemical-hunger-p...

spywaregorilla 5y ago
I don't particularly buy it. Again, sure, maybe it has a statistically significant effect, but it is undoubtedly dwarfed by people chugging sugary drinks and being more sedentary. A casual search suggests sugar consumption has increased 9 fold since the 1800s and 2 fold since the 1900s. The poor in particular are cornered into purchasing sugary foods due to weird economics around corn subsidies. And what do you know? They're the fattest by far. If it were mostly environmental you'd see broader gains. variation. But in my little bubble in upper middle class Massachusetts, I don't know ANYONE who is obese. In other areas of the country it's hard to find anyone who isn't.
- atom_arranger 5y ago
  The linked site does suggest a reason Massachusetts would have less overweight people, based on their exposure to environmental contaminants.
  - spywaregorilla 5y ago
    Sure. But you'll find plenty of fat people in poorer areas of massachusetts.
- orwin 5y ago
  Maize fructose has probably a bigger effect than cane sugar, because it also hit poor populations.
marcosdumay 5y ago

wyager 5y ago

There is probably some bidirectional causality between decreasing T levels and rising obesity.

eloff 5y ago
I think that's pretty firmly established. It's also a leading cause of ED.
- hnuser123456 5y ago
  So is circumcision.
  - eloff 5y ago
    That's the opposite of firmly established. I say that as no fan of the practice.
    - copperx 5y ago
      It took me a few seconds to realize your comment was a pun.

JohnWhigham 5y ago

BPA/BPB in plastics is another source. Unfortunately, this one is basically unavoidable since even if one doesn't own any of those plastics at home, there's bound to be some food product that uses a plastic container. Even more so, we don't know anything about how long it takes to leach into the food, what plastics do/don't contain it, stuff like that. Plastics should just be banned from touching food entirely.

pvarangot 5y ago
I think it really depends on the food. Like processed or skinned meat absorbs more than seeds or dry food, frozen absorbs less, or something like that. I haven't read about it for a while but that's what I remember was kind of like the consensus about where to start looking into if it's feasible to ban BPA.
pxeboot 5y ago
If you have running water in your home, every drop likely flows through hundreds of feet to miles of plastic pipe before you drink it. Even if you have a private well and copper plumbing, your pump and other components almost always contain plastic parts that make contact with the water.

rich_sasha 5y ago

I thought I remember reading it is dropping across the line, including for fit and healthy individuals. Is that not right, and if it is, what could that mean? Sorry for lack of source, it’s not my area.

spywaregorilla 5y ago
I can recall only one article that was posted here which included that, but I came away thinking it was misleading. It binned weight categories(e.g. BMI ranges from X-Y) and showed that over time, people were falling into heavier categories, and that sperm outcomes were getting worse in every category (heavily in the obese, less so in the normal weight range). But if you eyeballed the curve it felt very likely that the distribution of individuals was just shifting the the heavier end within each category. E.g. if a healthy BMI is 18-25, and you look at the the average outcome for that group over time... if the whole population gets fatter then the mean value in the 18-25 group could shift from 20 to 22. So... take it as you will. Sorry for no source here either.

giantg2 5y ago

It seems like a combination of issues. The obesity thing tends to hold across many other species too. I would guess you are right about this being the main driver. A classic example would be dealing with animal husbandry and obese pigs. Fertility in obese females can be impacted too. A variety of toxins have been shown to cause fertility issues too, such as lead and pesticides. It's also possible that estrogen and estrogen mimicking compounds found in drinking water could fall into this category (estrogen can adversely affect male fertility). Testoterone is also a factor which has seen a large decline over the last 50 years. Obesity and sedentary lifestyle can cause a decline in testorerone and other hormones/enzymes related to sperm. Then there's a possible link to RF reducing sperm quality. Although I think this is probably a secondary factor that might exacerbate the others.

jxramos 5y ago
That's an interesting idea, but I'm not sure the anatomy lines up. Like the mass of belly fat and fatty liver pressing down from above in upright humans resting on the pudendal artery wouldn't be the same as how the mass hangs on quadrupeds. This is an interesting line of thought too, like what organs get compressed under gravity from increased mass assuming it's primarily a mechanical problem.
- giantg2 5y ago
  I'm not talking about anatomy, but rather physiology (obesity affects hormones related to sperm). Do you have some information to suggest this is an anatomical issue (other than sleep apnea) rather than physiological one?
  - jxramos 5y ago
    nothing specific other than speculating about hearing about stuff around that bottom part of the body: lower sperm count, slower bowel movements with constipation and stuff. I wonder if there's anything else anatomical down there that could potentially get disrupted from extra mass bearing down on it.

newaccount2021 5y ago

If it truly is obesity at work, then the research will be buried. There are too many obese people...they could elect a President if they wanted. You can't offend them. The CDC director refuses to finger-wag at the US public even though there is a solid correlation between obesity and covid outcomes. Why can't we say this? No politician is willing to tick off the obese, that's why.

omgwtfbyobbq 5y ago

Do you have any links? Offhand I would suspect exercise, but I guess that's hard to differentiate from obesity.

spywaregorilla 5y ago
Studies correlating obesity and poor sperm quality are numerous and easy to find. https://www.hsph.harvard.edu/news/hsph-in-the-news/excess-weight-sperm-fertility/ https://www.hsph.harvard.edu/news/hsph-in-the-news/excess-we... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3521747/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3521747/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5657098/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5657098/ You can find more without much effort. What I don't see are epidemiological studies trying to track the prevalence of obesity vs. the average sperm quality across different nations. Unfortunately.

betwixthewires 5y ago

Or perhaps the correlation between obesity and low fertility is not causation, obesity could very well be a symptom of whatever is causing it, alongside low fertility.

spywaregorilla 5y ago
Obesity is fairly well documented to cause poor fertility in animal studies

supperburg 5y ago

People who eat meat and animal fat and cut out sugar report getting pregnant after years of not being able to. They also report iso-caloric weight loss, resolution of diabetes 2, thickening of hair and many other positive health heuristics. Obesity, diabetes and metabolic considerations are an absolute powder-keg of medical progress just waiting for mainstream acceptance

watwut 5y ago
The people getting pregnant after eating meat are unlikely to be men.

poorjohnmacafee 5y ago

If obesity it perhaps should be studied as a realtime pushback against modern diets by nature/natural selection, in reducing unhealthy people from the gene pool.

spywaregorilla 5y ago
Obese people are not intrinsically unhealthy. They're usually just unable to access reasonable nutrition.
- poorjohnmacafee 5y ago
  Risks for cardiovascular disease, stroke, cancer, and of course diabetes, are all significantly increased with obesity. Risk of getting severe covid-19 is significant increased with obesity. I know plenty of relatively wealthy people who are fat or even skinny fat (arguably worse condition), it's not only about access to reasonable nutrition.