11 ms·
The study states the majority of the effect is for fairly predictable causes like age and obesity, but I found this interesting: > After controlling for confou
by helen___keller 6y ago
The study states the majority of the effect is for fairly predictable causes like age and obesity, but I found this interesting:
> After controlling for confounders—including year of study, age, race, BMI, comorbidity status, alcohol and smoking use, and level of physical activity—total testosterone was lower among men in the later (2011-2016) versus earlier (1999-2000) cycles (P < 0.001)
Excluding all those confounders, there's not much we're left with. Environmental toxins?
- admiralspoo 6y agoWhy does it have to be toxins? What about diet?
- gameswithgo 6y agowould need to be dietary changes that don't also change BMI, since that was controlled for.
- godshatter 6y agoI wonder if soil depletion of minerals and vitamins due to over farming couldn't also be a suspect here. It's a problem I haven't heard much about lately.
- NoPicklez 6y agoWhich I think is a bit of a gaping hole. As a male who has been around 70kg for all of my adult life, I have consumed many different "diets". All from eating whole foods to eating more processed foods and easy packaged meals/junk food, all not impacting my BMI.
- waihtis 6y agoPlastics?
- lom888 6y agoThis is a common theory. https://www.npr.org/2011/03/02/134196209/study-most-plastics-leach-hormone-like-chemicals https://www.npr.org/2011/03/02/134196209/study-most-plastics...
- gameswithgo 6y agotime spent outdoors?
- Someone1234 6y agoLow vitamin D (i.e. low sun exposure), has been shown to reduce testosterone levels: > Compared to baseline values, a significant increase in total testosterone levels (from 10.7 ± 3.9 nmol/l to 13.4 ± 4.7 nmol/l; p < 0.001), bioactive testosterone (from 5.21 ± 1.87 nmol/l to 6.25 ± 2.01 nmol/l; p = 0.001), and free testosterone levels (from 0.222 ± 0.080 nmol/l to 0.267 ± 0.087 nmol/l; p = 0.001) were observed in the vitamin D supplemented group. By contrast, there was no significant change in any testosterone measure in the placebo group. Our results suggest that vitamin D supplementation might increase testosterone levels. Further randomized controlled trials are warranted to confirm this hypothesis. https://pubmed.ncbi.nlm.nih.gov/21154195/ https://pubmed.ncbi.nlm.nih.gov/21154195/
- MeinBlutIstBlau 6y agoSpending time behind a screen more than with people. Compounded with more desk jobs too.
- raverbashing 6y agoThere's apparently also a slight decrease in body temperature during the 20th century (not sure if it's men only or all people) Related?
- HDMI_Cable 6y agoWouldn't a decrease in temperature result in more testosterone? Since sperm production is optimal at 35C.
- iheartblocks 6y agoI believe that the reduction in temperature is generally attributed to lower levels of inflammation, which in turn is likely caused by reduced exposure to disease
- deleted 6y ago[deleted]
- eloff 6y agoCould be something in the environment, something in our diet. I'm curious if it's porn. Supposedly masturbation reduces testosterone levels. [1] Maybe men are just wanking more because of access to porn?
- eloff 6y agoFor some reason I can't edit my comment to add the link to the study. This study shows a 45% spike in testosterone after 7 days of abstinence. https://pubmed.ncbi.nlm.nih.gov/12659241/ https://pubmed.ncbi.nlm.nih.gov/12659241/
- toxik 6y agoHuh, that actually makes a lot of sense. I guess then if you want gains, stop a-spankin’. Is that true?
- zug_zug 6y agoI'm fairly sure these studies control for recency of masturbation (I know sperm-count studies do)
- iheartblocks 6y agoI see this study referenced frequently, and it's always seemed dubious. Why would there be a spike at exactly 7 days of abstinence, before returning to baseline? It's possible that the measuring apparatus was improperly calibrated on that day. Has this study been reproduced?
- The_rationalist 6y agoGenetic degradation of the human race?
- bencollier49 6y agoI don't know why this was voted down. We've been performing in vitro fertilisation en masse since the 1980s. All of a sudden, men with non-motile sperm are fathering children. So as a single cause it's not that massive, but at 1% of all births, the effects will soon stack up.
- worker767424 6y agoAlso that reducing infant mortality rate and other early death rates means the weak ones live long enough to breed. Unlike IVF, this just stalls genetics. IVF actively selects for fertility issues.
- throwaway5752 6y agoDiminishing role of strength and aggression as a factor in reproductive success?
- trianglem 6y agoDefinitely not a worldwide phenomenon.
- jointpdf 6y agoPossibilities: - stress/anxiety/depression - sleep deprivation/disruption - high-speed internet access (—> overuse of porn)
- zanethomas 6y agoand soy!
- iamatworknow 6y agohttps://pubmed.ncbi.nlm.nih.gov/20378106/ https://pubmed.ncbi.nlm.nih.gov/20378106/
- danbolt 6y agoI think if the phytoestrogens found in soy-based foods had an effect on testosterone levels anywhere close to estradiol, we'd see feminine transgender people using them as part of hormone-replacement therapy. It tends not to happen though, as soy-based foods aren't really effective at feminizing men.
- eeZah7Ux 6y agoThe fear of phytoestrogens is completely unfounded. Funnily enough, some men that are concerned about estrogen intake through food do stop stop eating cow meat. A female mammal that, unsurprisingly, produces tons of estrogen.
- jodrellblank 6y ago"Soy Boys: A Measured Response" - https://www.youtube.com/watch?v=C8dfiDeJeDU https://www.youtube.com/watch?v=C8dfiDeJeDU
- RobRivera 6y agoi personally chime in my antidote towards stress and sleep deprivation. a year after significant reduced stress and better sleep hygeine I'm seeing better test levels and performance in the gym.
- 6y ago
- jackallis 6y agochild rearing and geopolitcal conflict i.e War and conflict. whole point of testosterone, being tad reductionist here, is, atleast in the wild, to make you alpha male - agressiveness to defend. and if you look at 1900s, it was mired with geopolitial conflict, probably causing men to lead universally aggressive life. now to post 1990s, things have dramitcally changed.
- toxik 6y agoWhat if the geopolitical climate is a result of testosterone levels in the population?
- waihtis 6y agoThat’s where you get into interesting territory. It’s not a wild suggestion, is it?
- jackallis 6y agothis is where you get into the conversation about chicken and egg. my hypothesis was geoclimate could have led to increased level of testosterone in Men, not other way around. What you asked will lead us to ask the the first origin of increased T
- floatingatoll 6y agoIs 'wealth' one of the confounding factors they controlled for? In inflation-adjusted terms, most US workers saw a reduction in net wages after necessary expenses over this ten year period.
- eeZah7Ux 6y agoWhy the downvotes? There's been a skyrocketing increase in consumption of junk food in low-wage worker class who often can't find the time to cook and cannot afford more expensive healthy food.
- throwaway0a5e 6y agoThat relative reduction in wages happened over the same time living standards skyrocketed (turns out if you offshore everything the newly poor people can afford slightly better material conditions because everything is so much cheaper) so you're gonna have a hell of a time separating the effects.
- floatingatoll 6y agoYes. I ask because relative reduction in wages would decrease access to foods with a high density of unprocessed and non-fortified nutrients, regardless of the quality of the non-edible materials in their life. When combined with the tendency of US food to decrease in total non-fortified nutrient value over time, it could influencing the human body's hormone production.
- lazyjones 6y agoHow about natural selection putting men with physical traits like body hair at a disadvantage due to modern beauty standards?
- voldacar 6y agotraces of plasticzers, which can act as endocrine disruptors, are found basically everywhere in modern civilization
- stevenmays 6y agoI read a hypothesis that it's birth control going to waste water facilities, and then getting back into the drinking water supply. From what I read a charcoal filter lessens the effects - which I believe gets filtered through a normal refrigerator filter. Please verify this information first, it's all conjecture and hypothesis.
- kibwen 6y agoBirth control pill usage is slowly but inexorably declining as younger demographics start to favor IUDs more; IUDs were virtually unknown circa 2000 but today they're about equal in popularity. If true then we would expect the above trend to reverse within 20 years.
- tachyonbeam 6y agoModern IUDs release hormones.
- kibwen 6y agoThey release progestin, not estrogen. And even then they seem to release a 3-7x lower volume of hormones per day than pills. I also would ask for a source on the relative popularity of the hormonal IUDs vs the non-hormonal copper ones; I haven't seen any source provide that sort of breakdown.
- tachyonbeam 6y agoProgestins suppress testosterone too. I don't have stats but I believe hormonal IUDs are the most popular form nowadays.
- WA 6y agoCopper IUDs still exist for several reasons and they work pretty well without hormones.
- mobilejdral 6y ago
- downrightmike 6y agoplastics and estrogen similar molecules they let off
- asdff 6y agoSimple explanation: americans get less sleep today than they did 20 years ago. https://www.cbsnews.com/news/americans-get-less-sleep-than-20-years-ago/ https://www.cbsnews.com/news/americans-get-less-sleep-than-2...
- sp3000 6y agoBingo. One aspect of this is sleep (quantity and quality). The drop in testosterone is likely multifactorial though: sleep, nutrition, movement, stress -> all contributors that have the potential to decrease testosterone levels and creat hormone imbalances.
- asdff 6y agoStress is also on the rise, especially among gen Z: https://www.apa.org/news/press/releases/stress/2020/report-october https://www.apa.org/news/press/releases/stress/2020/report-o... Which shouldn't be surprising given the quality of life a typical worker enjoys today vs in decades past when cost of living was much more in line with wages.
- presentation 6y agoAlso, having recently watched The Social Dilemma, social media might be stressing people out too.
- markus_zhang 6y agolower real income for working class.
- yariik 6y ago> Environmental toxins? Almost. It's the plastics.
- knuthsat 6y agoExcluding all confounders in a study like this is statistical error. You cannot do that stuff mathematically with such noisy data. Similar mistakes happen when someone tries to show meat is cancerous or increases all cause mortality.
- ip26 6y agoThere's the cellular modem constantly in our pockets, inches from the gonads responsible for producing testosterone.