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Comment by defrost | Hacker News Reader

March 7, 2022 - Proceedings of the National Academy of Sciences

Half of US population exposed to adverse lead levels in early childhood

https://www.pnas.org/doi/10.1073/pnas.2118631119

Choice Quote:

    Significance

    We estimate population-level effects on IQ loss and find that lead is responsible for the loss of 824,097,690 IQ points as of 2015.

( The link given here on HN is to an NBC news article from March 8, 2022, about that PNAS publication. )

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"The average lead-linked loss in cognitive ability was 2.6 IQ points per person as of 2015."

Or, given at least half the US population was non urban | non built up areas for the bulk of the leaded gasoline years, it might something like "half the population lost at least 5 IQ points".

Distributions are often more interesting than averages or medians alone.

IQ points are normally distributed results of IQ tests, so the average is the median and you already know the distribution. I guess they should say how the SD changed though.

Reporting a loss of theoretical IQ points is weird terminology since IQ people want you to believe it's measuring something that exists called "g", but then they don't report this result as a loss of "g". Of course they also happily claim every other test that produces a number like the SAT is also a true measurement of your intelligence and you're doomed to never be able to increase it. Basically they just believe any statement as long as it's got numbers in it and it says something they like.

The geographic distribution of the population affected by lead - it seems clear that car dense populations would be more affected that open sparse rural populations, and so the question of distribution of exposure levels across humans becomes of interest.

About the same cognitive impairment associated with a mild and fully resolved case of COVID-19.

I find it hard to understand why cognitive impairment due to COVID-19 is not discussed more.

Cognitive impairment is a terrifying idea but I think it’s important to balance the risk of COVID-associated cognitive impairment with the risk of cognitive decline that would result from whatever social isolation would be necessary to avoid COVID.

Is cognitive decline due to COVID really comparable to that of lead exposure? If so, I’d really appreciate more concrete information to put the risk into context.

for anyone else looking for that citation i presume jeffbee referring to https://www.nejm.org/doi/full/10.1056/NEJMoa2311330

It’s worth noting the conclusion includes “Longer-term persistence of cognitive deficits and any clinical implications remain uncertain.”

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