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> On average, lead levels in children’s blood at the peak of the Roman empire could have risen 2.4 micrograms per decilitre, the researchers found, reducing the

> On average, lead levels in children’s blood at the peak of the Roman empire could have risen 2.4 micrograms per decilitre, the researchers found, reducing their IQ by 2.5 to 3 points. When taking background lead into account, childhood blood levels may have reached about 3.5 micrograms per decilitre. > A 2021 study by the Centers for Disease Control and Prevention in the US found blood levels in children aged one to five years fell from 15.2 to 0.83 micrograms per decilitre between the late 1970s and 2016 as leaded fuels were banned.

luxuryballs 2y ago
[flagged]
- CyberDildonics 2y ago
  Lots of people across the world don't have fluoride in their water, you could compare populations right now. https://en.wikipedia.org/wiki/Water_fluoridation_by_country https://en.wikipedia.org/wiki/Water_fluoridation_by_country
  - davorak 2y ago
    I doubt you can do a clean comparison, likely too many confounding factors, at least to pull anything out easily.
    - CyberDildonics 2y ago
      If someone thinks they can figure out 1500 years from now if the 'fall of the west' was because of fluoride, it's probably easier to look at the countries in the west that do and don't use it now.
      - luxuryballs 2y ago
        that’s the joke, today we are like “huh… lead in water, IQ, fall of Rome!” and that was more than 1500 years ago I think
- SteveNuts 2y ago
  Why specifically call out fluoride?
  - luxuryballs 2y ago
    Didn’t studies come out connecting it to lower IQ? Places are pulling it or planning to pull it, nothing to do with RFK.
  - lolinder 2y ago
    It's a bit of a thing with a particular political persuasion in the US right now (RFK Jr has made his anti-fluoride position a big part of his deal for his future role as Secretary of Health and Human Services), and there was a report in the news recently that some see as backing up the claims against fluoride: https://www.latimes.com/science/story/2025-01-06/what-a-new-study-does-and-doesnt-say-about-fluoride-and-its-link-to-iq https://www.latimes.com/science/story/2025-01-06/what-a-new-... It's not as conclusive a study as some people might claim, though: > For starters, 52 of the 74 studies were judged by the report authors to have a “high risk of bias.” That undermines the validity and reliability of their results. > Another issue is that most of the studies considered fluoride exposures far above the target level for the U.S. ... Only seven of the studies assessed children whose water contained less than 1.5 mg/L of fluoride. When they were considered on their own, there was no relationship between fluoride exposure and IQ.
    - kylebenzle 2y ago
      > It's a bit of a thing with a particular political persuasion... That seems dismissive as hell, especially since the US is the odd man out here by choosing to medicate their water supply. You could have simply answered that both fluoride and lead seem to lower IQ so using either as an additive would be questionable.
      - lolinder 2y ago
        > You could have simply answered that both fluoride and lead seem to lower IQ so using either as an additive would be questionable. This would have inaccurately reflected my understanding of the science: the link between fluoride and IQ is far more tenuous than lead at this point. See the study in the link above. > That seems dismissive as hell, especially since the US is the odd man out here by choosing to medicate their water supply. It's not intended to be dismissive, it's the primary reason why someone would have fluoride and IQ on their mind at the moment.
thaumasiotes 2y ago
> reducing their IQ by 2.5 to 3 points I seem to recall reading an article that observed that every time we do a study of the effect of lead exposure on IQ, it gets larger. IQs aren't changing much, but lead exposure is going down, and so we keep imputing the same IQ gaps to ever-smaller quantities of lead.
- trimethylpurine 2y ago
  IQs aren't changing much Isn't IQ a comparative representation of one's standing within their contemporary age group? My understanding is that within a given group the median should be 100. So you won't see it change between groups. This is highly relevant when you're talking about different groups being exposed to different concentrations of lead. As an extreme example to make the point, if people born in 1970 were all exposed to high concentrations of lead and were all morons as a result, their median IQ is still 100. Then people born in 2000 are exposed to far less lead and are super smart, but their median IQ would still be 100. Points above or below 100 are merely a specification of how many fractions of a standard deviation above or below that median within the given age group a person's performance is measured to be. That said, even within a group, 2.5 - 3 points seems largely insignificant as an individual's score might vary more than this depending on which day of the week they took the test. It seems a big stretch to draw any scientific conclusion from such a small variance.
  - thaumasiotes 2y ago
    You're basically right about the relative nature of IQ scores, but you're wrong about the comparison being drawn. To impute the effect of lead, you look at a bunch of people, measure the amount of lead in their blood, measure their IQs, and see how much of a difference there is between people with a lot of lead and people with less or none. Modern poor people who live in crummy areas where there's still a little bit of lead are about as stupid, relative to the leadless elite, as poor people from decades past who lived in crummy areas which, at the time, had a lot more lead than they do now. It seems like a safe assumption that the effect of lead on people with negligible lead levels has stayed constant over the decades at indistinguishable-from-zero. But for lead to explain the gap between the lead-haves and the lead-have-nots, its effect must have increased dramatically over that same period. That gap hasn't changed. But lead levels have plummeted.
nahnahno 2y ago
2.5-3 micrograms per deciliter is nothing. Wouldn’t even come up as elevated by current childhood screening guidelines. I very much doubt 2-3 IQ point difference.
- HeatrayEnjoyer 2y ago
  I wouldn't call it nothing. Current regulation requires water supply at the tap to measure <10 µg/L, changing to <5 µg/L next decade. 2-3 µg/L is significant.
  - elcritch 2y ago
    Worse the parent says 2-3 μg/dL or 20-30 μg/L right?
  - s1artibartfast 2y ago
    You are comparing level in the blood and water.
    - HeatrayEnjoyer 2y ago
      I am referencing water regulations, I never said anything about blood.
- cma 2y ago
  That's the average, so it would be much high the cities in the cities than rurally right?
rayiner 2y ago
Wow. We mock those stupid Romans for putting lead in their drinking water supply, but we literally vaporized it and had everyone inhale it for decades so it'd go straight to the bloodstream.
- 0_____0 2y ago
  Still do :) all the GA piston planes flying above you are still running leaded fuel.
  - cjrp 2y ago
    The majority, but not all - some run on UL91 or even "mogas" (unleaded fuel from the petrol station).
    - 0_____0 2y ago
      Some of the smaller airports in the Bay Area (HWD, RHV, SQL) have UL94 but not all (PAO, HAF, and the large ones SJC, SFO, OAK don't). Fuel from a petrol station off field doesn't do you a lot of good, and it really doesn't help if you're refueling en route.
      - schiffern 2y ago
        Incidentally, aerospace Youtuber Scott Manley just did an excellent deep dive on lead in aviation gas. https://www.youtube.com/watch?v=8zfIy17q9sE https://www.youtube.com/watch?v=8zfIy17q9sE
- mistrial9 2y ago
  > we literally vaporized it and had everyone inhale it for decades this is a massive scandal that has not been fully understood in public AFAIK. Extensive documentation of the false premise of leaded gasoline has been published, e.g. https://www.thenation.com/article/archive/secret-history-lead/ https://www.thenation.com/article/archive/secret-history-lea...

luxuryballs 2y ago

[flagged]

CyberDildonics 2y ago
Lots of people across the world don't have fluoride in their water, you could compare populations right now. https://en.wikipedia.org/wiki/Water_fluoridation_by_country https://en.wikipedia.org/wiki/Water_fluoridation_by_country
- davorak 2y ago
  I doubt you can do a clean comparison, likely too many confounding factors, at least to pull anything out easily.
  - CyberDildonics 2y ago
    If someone thinks they can figure out 1500 years from now if the 'fall of the west' was because of fluoride, it's probably easier to look at the countries in the west that do and don't use it now.
    - luxuryballs 2y ago
      that’s the joke, today we are like “huh… lead in water, IQ, fall of Rome!” and that was more than 1500 years ago I think
SteveNuts 2y ago
Why specifically call out fluoride?
- luxuryballs 2y ago
  Didn’t studies come out connecting it to lower IQ? Places are pulling it or planning to pull it, nothing to do with RFK.
- lolinder 2y ago
  It's a bit of a thing with a particular political persuasion in the US right now (RFK Jr has made his anti-fluoride position a big part of his deal for his future role as Secretary of Health and Human Services), and there was a report in the news recently that some see as backing up the claims against fluoride: https://www.latimes.com/science/story/2025-01-06/what-a-new-study-does-and-doesnt-say-about-fluoride-and-its-link-to-iq https://www.latimes.com/science/story/2025-01-06/what-a-new-... It's not as conclusive a study as some people might claim, though: > For starters, 52 of the 74 studies were judged by the report authors to have a “high risk of bias.” That undermines the validity and reliability of their results. > Another issue is that most of the studies considered fluoride exposures far above the target level for the U.S. ... Only seven of the studies assessed children whose water contained less than 1.5 mg/L of fluoride. When they were considered on their own, there was no relationship between fluoride exposure and IQ.
  - kylebenzle 2y ago
    > It's a bit of a thing with a particular political persuasion... That seems dismissive as hell, especially since the US is the odd man out here by choosing to medicate their water supply. You could have simply answered that both fluoride and lead seem to lower IQ so using either as an additive would be questionable.
    - lolinder 2y ago
      > You could have simply answered that both fluoride and lead seem to lower IQ so using either as an additive would be questionable. This would have inaccurately reflected my understanding of the science: the link between fluoride and IQ is far more tenuous than lead at this point. See the study in the link above. > That seems dismissive as hell, especially since the US is the odd man out here by choosing to medicate their water supply. It's not intended to be dismissive, it's the primary reason why someone would have fluoride and IQ on their mind at the moment.

thaumasiotes 2y ago

> reducing their IQ by 2.5 to 3 points I seem to recall reading an article that observed that every time we do a study of the effect of lead exposure on IQ, it gets larger. IQs aren't changing much, but lead exposure is going down, and so we keep imputing the same IQ gaps to ever-smaller quantities of lead.

trimethylpurine 2y ago
IQs aren't changing much Isn't IQ a comparative representation of one's standing within their contemporary age group? My understanding is that within a given group the median should be 100. So you won't see it change between groups. This is highly relevant when you're talking about different groups being exposed to different concentrations of lead. As an extreme example to make the point, if people born in 1970 were all exposed to high concentrations of lead and were all morons as a result, their median IQ is still 100. Then people born in 2000 are exposed to far less lead and are super smart, but their median IQ would still be 100. Points above or below 100 are merely a specification of how many fractions of a standard deviation above or below that median within the given age group a person's performance is measured to be. That said, even within a group, 2.5 - 3 points seems largely insignificant as an individual's score might vary more than this depending on which day of the week they took the test. It seems a big stretch to draw any scientific conclusion from such a small variance.
- thaumasiotes 2y ago
  You're basically right about the relative nature of IQ scores, but you're wrong about the comparison being drawn. To impute the effect of lead, you look at a bunch of people, measure the amount of lead in their blood, measure their IQs, and see how much of a difference there is between people with a lot of lead and people with less or none. Modern poor people who live in crummy areas where there's still a little bit of lead are about as stupid, relative to the leadless elite, as poor people from decades past who lived in crummy areas which, at the time, had a lot more lead than they do now. It seems like a safe assumption that the effect of lead on people with negligible lead levels has stayed constant over the decades at indistinguishable-from-zero. But for lead to explain the gap between the lead-haves and the lead-have-nots, its effect must have increased dramatically over that same period. That gap hasn't changed. But lead levels have plummeted.

nahnahno 2y ago

2.5-3 micrograms per deciliter is nothing. Wouldn’t even come up as elevated by current childhood screening guidelines. I very much doubt 2-3 IQ point difference.

HeatrayEnjoyer 2y ago
I wouldn't call it nothing. Current regulation requires water supply at the tap to measure <10 µg/L, changing to <5 µg/L next decade. 2-3 µg/L is significant.
- elcritch 2y ago
  Worse the parent says 2-3 μg/dL or 20-30 μg/L right?
- s1artibartfast 2y ago
  You are comparing level in the blood and water.
  - HeatrayEnjoyer 2y ago
    I am referencing water regulations, I never said anything about blood.
cma 2y ago
That's the average, so it would be much high the cities in the cities than rurally right?

rayiner 2y ago

Wow. We mock those stupid Romans for putting lead in their drinking water supply, but we literally vaporized it and had everyone inhale it for decades so it'd go straight to the bloodstream.

0_____0 2y ago
Still do :) all the GA piston planes flying above you are still running leaded fuel.
- cjrp 2y ago
  The majority, but not all - some run on UL91 or even "mogas" (unleaded fuel from the petrol station).
  - 0_____0 2y ago
    Some of the smaller airports in the Bay Area (HWD, RHV, SQL) have UL94 but not all (PAO, HAF, and the large ones SJC, SFO, OAK don't). Fuel from a petrol station off field doesn't do you a lot of good, and it really doesn't help if you're refueling en route.
    - schiffern 2y ago
      Incidentally, aerospace Youtuber Scott Manley just did an excellent deep dive on lead in aviation gas. https://www.youtube.com/watch?v=8zfIy17q9sE https://www.youtube.com/watch?v=8zfIy17q9sE
mistrial9 2y ago
> we literally vaporized it and had everyone inhale it for decades this is a massive scandal that has not been fully understood in public AFAIK. Extensive documentation of the false premise of leaded gasoline has been published, e.g. https://www.thenation.com/article/archive/secret-history-lead/ https://www.thenation.com/article/archive/secret-history-lea...