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Roman Empire's use of lead lowered IQ levels across Europe, study finds

theguardian.com

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Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#41

Post by maest »

kylebenzle wrote: post #33
lolinder wrote: post #28

Earlier quoted context omitted.

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-... It's not as conclusive a study as some peop…

> 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.

> the US is the odd man out here by choosing to medicate their water supply

It is not: https://en.wikipedia.org/wiki/Water_fluoridation_by_country

Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#42

Post by trimethylpurine »

thaumasiotes wrote: post #23
curmudgeon22 wrote: post #3

> 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 t…

> 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.

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.

Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#43

Post by cmrdporcupine »

perihelions wrote: post #40
cmrdporcupine wrote: post #10

Similarly, arsenical bronze (copper + arsenic) was common before tin started to be used, and I've often wondered how common arsenic poisoning was in the copper age / early bronze age. When we think of the nastiness of industry, it's often industrial 19th century Britain and so on, but some of these villages (often quite remote) back then were full on industrial sites with massive smelting operations and the entire po…

There's a new study that suggests, actually not so much: https://news.ycombinator.com/item?id=42513706 ( "Ancient copper industry in King Solomon's mines did not pollute environment ") - "...We took hundreds of soil samples from both sites for chemical analyses, creating high-resolution maps of heavy metal presence in the region. We found that pollution levels at the Timna copper mining sites are extremely low and co…

Interesting. Thanks

Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#44

Post by thaumasiotes »

trimethylpurine wrote: post #42
thaumasiotes wrote: post #23

Earlier quoted context omitted.

> 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.

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…

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.

Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#45

Post by PeterHolzwarth »

WorkerBee28474 wrote: post #25
PeterHolzwarth wrote: post #15

I have no idea if this is true (and honestly can only barely remember the reference, which I read maybe a decade or two ago), but I believe I saw a comment that the interior of lead pipes eventually develop a "calcified" (don't know what else to call it) lining of the lead reacting to water, such that lead stops leeching into the water that passes through the pipes. I believe this came up when reading something about…

I haven't read it, but the book History of Toxicology and Environmental Health [0] would say that pipes were not a problem. Preparing food and wine in lead containers could have been a problem, but it wasn't until centuries after the Roman Empire "fell" that doctors even described the symptoms of lead poisoning. And to throw in another quote from a scholarly source, "Water from the river Anio, which fed two of Rome's…

That's a great reply, thanks, and seems to align with the "pipes just get clogged up" concept I read some time ago.

Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#46

Post by peeters »

> Roman Empire’s use of lead lowered IQ levels across Europe, study finds

I'm not a fan of this phrasing. None of the findings had anything to do with measuring IQ levels in ancient Europe. They were about measuring historical levels of lead, which they then just plugged into modern models to presume some levels of cognitive effects.

A study that was actually able to measure cognitive disparities and correlate them with measured levels of lead would have been extremely interesting, but this is not that. Everything other than the measurements of historical lead levels seems to be fluff.

This would kind of be like saying "massive asteroid strike 100m years ago lead to cataclysmic tsunami, study finds" but then not showing any evidence of a tsunami, just evidence that it struck an ocean and the inference that that would have caused a tsunami. It might be a reasonable inference, it's just not as interesting as the title would make it seem.

Edit: I should qualify, I'm not trying to say that "they did the math"-style papers don't have value, just that the phrasing in how they are presented matters to me. If the phrasing was more like "Use of lead in Roman Empire would have lowered IQ levels across Europe, study finds" I would have no issue with it.

Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#47

Post by PeterHolzwarth »

WorkerBee28474 wrote: post #25
PeterHolzwarth wrote: post #15

I have no idea if this is true (and honestly can only barely remember the reference, which I read maybe a decade or two ago), but I believe I saw a comment that the interior of lead pipes eventually develop a "calcified" (don't know what else to call it) lining of the lead reacting to water, such that lead stops leeching into the water that passes through the pipes. I believe this came up when reading something about…

I haven't read it, but the book History of Toxicology and Environmental Health [0] would say that pipes were not a problem. Preparing food and wine in lead containers could have been a problem, but it wasn't until centuries after the Roman Empire "fell" that doctors even described the symptoms of lead poisoning. And to throw in another quote from a scholarly source, "Water from the river Anio, which fed two of Rome's…

I hope I can be forgiven for replying to myself, but at this timestamp, I've got three excellent replies affirming the "lead pipes get gunked up and it stops being a notable problem" concept.

Thanks for the replies! Great stuff from all of you.

Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#48

Post by lostlogin »

pea wrote: post #34
PeterHolzwarth wrote: post #15

I have no idea if this is true (and honestly can only barely remember the reference, which I read maybe a decade or two ago), but I believe I saw a comment that the interior of lead pipes eventually develop a "calcified" (don't know what else to call it) lining of the lead reacting to water, such that lead stops leeching into the water that passes through the pipes. I believe this came up when reading something about…

Yes, the piping in my parents’ house is all lead, but not worth replacing due to the above. It’s pretty common in old houses in Britain

If the water PH changes, the value in replacing those pipes might become more apparent.

Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#49

Post by PeterHolzwarth »

peeters wrote: post #46

> Roman Empire’s use of lead lowered IQ levels across Europe, study finds I'm not a fan of this phrasing. None of the findings had anything to do with measuring IQ levels in ancient Europe. They were about measuring historical levels of lead, which they then just plugged into modern models to presume some levels of cognitive effects. A study that was actually able to measure cognitive disparities and correlate them w…

Fully agree, @peeters - as I've mentioned elsewhere in these comments, there's a long-standing trend of trying to identify the one true cause of the fall of the Roman Empire. Each explanation falls short - it's just a complicated thing (and heck, the empire didn't really fall, it just shifted east.)

Re: Roman Empire's use of lead lowered IQ levels across Europe, study finds

#50

Post by alexey-salmin »

pea wrote: post #34
PeterHolzwarth wrote: post #15

I have no idea if this is true (and honestly can only barely remember the reference, which I read maybe a decade or two ago), but I believe I saw a comment that the interior of lead pipes eventually develop a "calcified" (don't know what else to call it) lining of the lead reacting to water, such that lead stops leeching into the water that passes through the pipes. I believe this came up when reading something about…

Yes, the piping in my parents’ house is all lead, but not worth replacing due to the above. It’s pretty common in old houses in Britain

I wonder how did you figure out this is the case, did you make any tests of the water?

I can hardly imagine living in a house with lead pipes. I mean even if water if provably safe today, what if tomorrow PH shifts to acidity.

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