Mostly in low/middle income countries.
> It's items in the kitchen that are poisoning them
On a positive note: This is something that can be fixed.
But it's weird that lead exposure has been dropping while the things it's supposed to cause don't seem to be decreasing in proportion to the lack of exposure.
Is the effect size or confidence rising? The latter makes sense. We're moving from a population systematically exposed to lead (no control) to one with lead-free kids for a change.
What is the effect of 1 μg of lead on IQ?
Good studies from the different research eras can be used to illustrate how lead effect sizes have changed over time.
Landrigan et al. (1975) represents the Early Era. In this study, there were 46 children in the high lead group and 78 in the control group. Their respective BLLs were 48.3 and 26.9 in 1972 and 40.5 and 26.5 in 1973, and they were 8.3 and 9.3 years old, respectively. So we have a gigantic 14 μg/dL gap between these groups. The high lead group had an average IQ of 88.02 versus 92.88 for the low lead group, or a 4.86 point IQ gap, and thus a per μg effect of 0.35 IQ points.
Baghurst et al. (1992) represents the Middle Era. In this study, there were 494 children who had IQ results, and they were divided into quartiles by BLLs. The mean concentrations of blood at assessment age were 6.6 μg/dL for the lowest quartile, 10.1 for the second, 13.7 for the third, and 20.0 for the final one. Their IQs were 109.6, 107.7, 102.7, and 98.7, respectively. Going from the lowest to the highest lead exposure quartiles, we have a BLL difference of 13.4 μg/dL and an IQ difference of 10.9 points. Going quartile to quartile, the effect of 1 μg of lead was 0.54 IQ points, 1.39 IQ points, and then 0.63 IQ points, with the aggregate (1 - 4) being 0.81 IQ points.
Kim, Yu & Lee (2010) represents the the Modern Era. In this study, there were 302 children who were median-split by BLLs. The high BLL group had a mean BLL of 3.74 and the low BLL group had a mean of 1.92 with IQs of 106.4 and 110, respectively. These differences of 1.82 μg/dL and 3.60 IQ points mean that the per μg/dL IQ drop was 1.98 points.
I sure am wondering how much of the late 20th century Flynn effect was due to diminishing lead poisoning.
Given that the Flynn effect seemed to be strongest in the era of high-lead petrol and has dropped off, I can't see how it could have had an effect
Is it that the toxin is correlated with another substance that is responsible for part of the harm? Is it corruption and the cleanups have been faked, leading to underreporting of exposure without underreporting of results? Or did you underestimate the harm at lower exposures (maybe because you underestimated the exposure of some of your subjects)?
Science is hard. As is public policy.
Corruption caused the original numbers to be incorrect, leading to anchoring in subsequent experiments.
It would have to do that be consistent with this claim that the sensitivities have gone up, unless both groups have trended down in lead levels non-linearly.
Is this a result of far lower standards in other places or just a result of that being the region that was tested for the report (the post doesn't say, it just mentions that samples were collected from developing countries).
This could very easily be a massive problem in the developed world too and you wouldn't know from the report here.
https://foodsafetyandrisk.biomedcentral.com/articles/10.1186...
Important quote: "The estimated daily dose of lead exceeded the California Maximum Allowable Dose Level of 0.5 μg per day for one of the five mugs tested."
Previous HN discussion:
To me it's mostly about the aesthetics. I've broken one or two over five years, but they are just too charming to give up on… Light, holds plenty of liquid, and good for pouring from.
Oh yeah, the beaker doubles as my metric-only measuring cup for cooking. It only has millilitre markings, no fluid ounce or cups at all.
> See, my terrible lecture on ADHD suggested several reasons for the increasing prevalence of the disease. Of these I remember two: the spiritual desert of modern adolescence, and insufficient iron in the diet. And I remember thinking "Man, I hope it’s the iron one, because that seems a lot easier to fix."
The discovery that we can dramatically reduce mortality by the relatively straightforward solution of using pots and pans that don't contain lead is a cause for excitement. Compare that to the solutions like "convince people to exercise more and eat less (or less tasty) food". We know how to make our dishes lead-free!
[0] https://slatestarcodex.com/2014/09/10/society-is-fixed-biolo...
(We shit on it now, but maybe this is why the "food pyramid" was shaped so contrary to current sensibilities? Or maybe it's a potassium deficiency mislabeled as something else.)
In general though, I wouldn't place the blame on plants, but on the low quality, highly processed diet the average person consumes.
I have ADHD, and I've noticed symptoms of low iron whenever I stray from my very low carb diet: restless legs, low energy, ADHD symptoms getting worse. Note that iron is a necessary component for the synthesis of dopamine. Given that I take amphetamine-based stimulants, which increase dopamine release as well as inhibiting reuptake, I might need a little more iron that usual.
Heh, great point.
> and many plants contain anti nutrients (phytic acid) that bind to metals, reducing their absorption, such as beans.
Also a good point, and will come back to it--
> I have ADHD, and I've noticed symptoms of low iron whenever I stray from my very low carb diet: restless legs, low energy, ADHD symptoms getting worse. Note that iron is a necessary component for the synthesis of dopamine.
Right. You make an excellent test candidate then-- is this speculative or have you actually tested your iron levels during those times?
I'd again question whether what you're feeling there might actually be a potassium/magnesium problem. You say "symptoms of low iron," and that's true in fact-- but it may only be low because you're consuming but not absorbing enough of it. I doubt you have much of an appetite.
Assuming you aren't bleeding out from gunshot trauma or menses, the next time you're feeling symptoms of what you're attributing to low iron, try eating a daily banana (or take prenatal vitamins or something).
That should be much easier and less expensive to do than eg, replacing lead pipes in the house or town/city that may be delivering poisoned drinking water.