The Studies Show Tom Chivers and Stuart Ritchie

Petrol, pipes, paint: they made a whole generation duller. That’s if you believe the research on the effects of lead on IQ. By interfering with neurological development, the lead that we used to encounter routinely has left hundreds of millions of us with a tiny bit of brain damage.
In this episode of The Studies Show, Tom and Stuart look at the toxic effects of lead - from very obvious, high-dose lead poisoning to the more insidious, low-level effects that have apparently held millions of people back. How strong is the evidence for the effects of low-level lead exposure on IQ?
The Studies Show is brought to you by Works in Progress magazine, a journal of ideas to accelerate human progress. If you’re a student aged 18-22 and want to attend the Works in Progress “Invisible College” this August (at which Stuart is speaking), take a look at this link.
Show Notes
* Centers for Disease Control (CDC) page on lead poisoning
* Articles on the history of lead poisoning from the BBC and the Guardian
* 2022 PNAS study concluding that “half of US population exposed to adverse lead levels in early childhood” (the one with the “824,097,690” figure)
* Article on blood lead levels and which are considered dangerous
* The 2005 meta-analysis on lead and children’s IQs
* Cited in the 2021 “Global Lead Exposure Report”
* The critique from the CDC in 2007
* The critique paper from 2013
* The critique paper from 2016
* The correction from 2019
* The critique paper from 2020
* Quasi experiments: from Rhode Island; using manufacturing employment
* 2018 paper on low-level lead and all-cause mortality
Credits
The Studies Show is produced by Julian Mayers at Yada Yada Productions.


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Preventing cancer. Curing depression. Single-handedly ending the COVID-19 pandemic. Oh, and something to do with your bones. Is there anything Vitamin D can’t do?
Maybe the answer is: “quite a lot”. In this episode of The Studies Show, Tom and Stuart look into the claims about the wondrous powers of Vitamin D supplements - and whether any of them have any decent evidence behind them. The whole story turns out to be a perfect parable for how to think about health research.
📚Buy Tom’s book, Everything is Predictable, at this link! And join us at the book launch in London on 16th May 2024! 📚
The Studies Show is brought to you by Works in Progress magazine: the stylish, well-argued, data-packed place to read essays about science, technology and human progress. Find their latest issue at this link.
Show notes
* Rupa Huq MP’s article from during the COVID pandemic on how the government should be “shouting about Vitamin D”
* Huq and David Davis MP convince the government to recommend Vitamin D
* Stuart’s New Statesman article on why this was jumping the gun a little
* How Vitamin D regulates calcium and phosphorus metabolism in the body
* Might it slow tumour growth? Or prevent cardiovascular disease? Evidence from rats
* Observational studies on how Vitamin D levels are related to: depression, cognitive impairment, cancer rates, cardiovascular disease, all-cause mortality
* Review paper claiming widespread deficiency in Vitamin D
* Scientific American article including discussion of the confusion over what it means to be “deficient” in, and/or have an “insufficiency” of Vitamin D
* 2019 paper reporting results from the VITAL trial on cancer and cardiovascular risk
* D-health trial results on cancer risk and cardiovascular risk
* From the D-health trial, papers reporting no effect of Vitamin D supplementation on: cognitive impairment, depression, microbiome diversity, telomere length, hypothyroidism, erectile dysfunction, falls, fractures
* Classic xkcd cartoon on false-positive jelly beans
* 2022 Nature Reviews Endrocrinology review on the (lack of) evidence for the effects of Vitamin D beyond bone-related problems
* Story of UK man who died of a Vitamin D overdose
* Vitamin D and COVID: the promising observational study; the null trial
Credits
The Studies Show is produced by Julian Mayers at Yada Yada Productions.


This is a public episode. If you’d like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

We can all agree that being lonely is bad. But apparently, science shows it’s really, really bad. Indeed, being lonely is so dangerous to your health that its equivalent to smoking 15 cigarettes a day. And it gets worse: we’re in the middle of a loneliness epidemic, meaning that the health of millions is at risk.
In this episode of The Studies Show, Tom and Stuart ask two questions: is there actually a loneliness epidemic? And does it make sense to compare loneliness to something as bad for you as smoking cigarettes?
The Studies Show is brought to you by Works in Progress magazine. Click here to see the latest issue, packed with essays on YIMBYism, clinical research, Russian history, railway tunnels, and more.
Show notes
* The US Surgeon General’s report into “Our Epidemic of Loneliness and Isolation”
* Articles on the loneliness epidemic from the BBC, NPR, the BBC again, the New York Times, the New York Times again, and Science magazine
* 2023 article in The Times (London) that makes the 15-cigarettes-a-day comparison
* The 2017 Jo Cox report on “Combatting Loneliness”
* 2010 meta-analysis of social relationships and mortality risk
* American Time Use Survey, 2003-2020
* Meta-Gallup poll from 2022 on “The Global State of Social Connections”
* Are US older adults getting lonelier (2019 study)? What about “emerging adults” (2021 meta-analysis)?
* Comparison between younger-old people and older-old people on their loneliness levels
* 2017 review study on the health effects of loneliness
* 2023: systematic review no.1, systematic review no.2, both into the effects of loneliness on health
* 2005 study on the health effects of smoking tobacco
Credits
* The Studies Show is produced by Julian Mayers at Yada Yada Productions.


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The evidence for puberty blockers and cross-sex hormones for young people with gender dysphoria is “remarkably weak”. That’s according to the Cass Review, a new in-depth report commissioned by NHS England.
As you might imagine, the report’s conclusions have been somewhat controversial. In this paid-subscriber-only episode of The Studies Show, Tom and Stuart read through the Cass Report, consider the arguments of its critics, and try to put the whole thing in context.

Several previous episodes of The Studies Show have covered depression and treatments for it, but none have really considered what depression is. It’s time to do that. It turns out that some scientists have made serious critiques of the standard way of thinking about depression, and argue that we need a revolution in the way we measure it.
In this episode of The Studies Show, Tom and Stuart take nothing for granted - they look into the idea of “latent variables”, read the studies critiquing the concept of a single, monolithic “depression”, and talk about what this all means for how we treat people with these often-terrible symptoms.
We’re proud to be sponsored by Works in Progress magazine, which is, as they put it, “a magazine of new and underrated ideas to improve the world”. You can find their beautifully-illustrated and detailed essays on all kinds of scientific and technological subjects at worksinprogress.co.
Show notes
* Our World in Data on depression prevalence
* And covering some of the problems in estimating depression prevalence
* Meta-analysis on antidepressant trials
* Study looking at how depression rates have (or haven’t) changed over time
* Article criticising the serotonin hypothesis of depression…
* …and a rebuttal
* Study showing how tricky it is to find replicable brain correlates of things like depression
* Eiko Fried’s website, with his blog and links to his papers
* Study on “the 52 symptoms of major depression”
* Study showing how depression measures might not be measuring the same thing over time
* Study showing that the same seems not to be true for intelligence
* Article “revisiting” (strongly critiquing) the theoretical and empirical basis for depression research
* A new-ish statistical way of thinking about the symptoms of depression: as part of a dynamic network
Credits
The Studies Show is produced by Julian Mayers at Yada Yada Productions.


This is a public episode. If you’d like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

Everything is Predictable: How Bayes' Remarkable Theorem Explains the World. That’s the new book—out on April 25 in the UK and May 7 in the US—by our very own Tom Chivers!
In this episode of The Studies Show, Tom and Stuart cover some of the historical sections of the book, and talk about where some of our basic ideas about probability come from (it turns out to be a weird combination of inveterate gamblers and Presbyterian ministers).
The Studies Show is sponsored by Works in Progress Magazine - the best place online to find deep discussions of the ideas that have driven human progress, and that might drive it even further in future. The latest issue of Works in Progress is available right now, at worksinprogress.co.
Show notes
* The only citation that matters this week: Tom’s new book, Everything is Predictable. It’s available NOW for pre-order in the UK, and in the US.
* And for those reading this on Substack, here’s the rather lovely front cover:
Credits
The Studies Show is produced by Julian Mayers at Yada Yada Productions.


This is a public episode. If you’d like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe