Must read piece on cholera and COVID by @NeilSinghHQ A brief thread on whether it's true that in Broad Street John Snow “had the handle of the pump removed which led to a sharp decline in cholera cases in Soho”. theguardian.com/society/2020/m…
2/n The data were published after Snow was dead by his friend the Reverend Henry Whitehead, who accompanied him on his visits to Soho and speculated (with no strong basis) that there may have been a resurgence of the outbreak if the handle had not been removed
3/n Snow’s achievement was not the Pump Handle (though it makes a good, usually mistold - story), it was his study of the water source for houses across London, and how that related to cholera cases, described in his 1854 book that @NeilSinghHQ discusses archive.org/stream/b289852…
4/n However what Snow reported wasn’t all it seemed, as Edmund Parkes' incredibly detailed 1855 review of Snow’s book discussed academic.oup.com/ije/article/42…
5/n Parkes pointed out that whilst Snow made it sound like he had individual level data, this wasn't the case. Parkes discusses what epidemiologists would now call "the ecological fallacy"
6/n It was this “peer review” that led Snow to undertake his definitive show leather epidemiological investigation, demonstrating the importance of individual household level water supply archive.org/stream/b289852…
7/n After the "Great Stink" of 1858 Joseph Bazalgette’s sanitation plan for clean water and efficient removal of sewage was advanced, cleaning up London and protecting against future cholera outbreaks academic.oup.com/ije/article/42…
8/8 Joseph Bazalgette was the great-grandfather of Peter Bazalgette who introduced “Big Brother” @bigbrotheruk
Whilst his ancestor pumped shit out of people’s houses the great grandson pumped shit into them & onto their TVs. Snow and co's whole story: academic.oup.com/ije/article/31…
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1/n In 2019 @BMJ_latest published a non-linear Mendelian randomization (NLMR) paper with the conclusion that gaining weight would reduce mortality risk in many people. The NLMR method produces spurious findings MR's credibility calamity in this 🧵 bmj.com/content/364/bm…
2/n The sad story of NLMR and the delays in journals and authors in issuing retractions of clearly spurious papers containing damaging public health messages that include *literally impossible* findings is told here /cont
Just seen that @ucl have made Lyndsay Farrall's 1969 PhD "The origins and growth on the English Eugenics movement" easily found with new intro by @profjoecain It remains perhaps the best overview of the topic, and deflates some myths. The survey of /contucl.ac.uk/sts/sites/sts/…
2/n the well-known members of the "Eugenics Education Society" and a random sample show academics and medical doctors the most common professions, that leftists as well as conservatives well represented, that Lamarckian eugenics was a thing (so much for the bizarre notion /cont
3/4 that transgenerational epigenetics in its soft inheritance form is somehow more progressive than genetics), that biometricians were as common as Mendelians amongst the early eugenicists. Essentially the desire to stop the working class reproducing was ahead of racism /cont
A brilliant 1984 chapter in the "Encyclopaedia of Medical Ignorance" by Richard Peto anticipated much of the advances in understanding of cancer since then, and is now accessible in @SpringerNature European Journal of Epidemiology. A personal🧵on it/ cont link.springer.com/article/10.100…
1/n I first read this sitting on a stool in the HK Lewis medical bookshop on Gower Street soon after it came out; the book was outside my budget & the rest not so interesting. It felt like the 19th century in Lewis' anachronistic shop, there were hardly any customers /cont
@Lyonpaul @mrc_ieu @SpringerNature @The_MRC 2/n no one seemed to buy anything and the rumour was it was a front for an MI5 office. I was left alone reading away, and was entranced by the sparkling language but must admit I understood hardly any of it. I recalled it when reprinting another Richard Peto chapter in/cont
A twee story on tea by @TorstenBell in @guardian suggests increased consumption of tea (using boiled water) led to a fall in mortality in Britain. This might be true, but there is no mention of how this was linked to massively increased deaths in India 🧵 theguardian.com/commentisfree/…
1/n The academic paper @guardain story is based on suggests that growing tea consumption by the working class after 1784 in Britain led to a fall in mortality. It uses what it calls "The Tea and Windows Act of 1784" which led to a dramatic fall /cont repec.iza.org/dp15016.pdf
@guardain 2/n in taxation on tea. There was no such act, though the 1784 Commutation act did decrease tax on tea from over 100% to 12.5%, and tea imports went up. Why was this act introduced? It was introduced on the behest of Richard Twinning - of Twinning's tea that some vanity /cont
In 2018 we published a non-linear Mendelian randomisation (NLMR) study in @ObesitySociety and it is now clear the method we applied is deeply flawed, so in October we published a Perspective correcting it. A 🧵on the cautionary tale of NLMR onlinelibrary.wiley.com/doi/epdf/10.10…
2/n Naïve observational studies report J- or U- shaped upturns of mortality at lower levels of BMI. Our paper using UK Biobank (UKB; @uk_biobank) data suggested overall adverse effects of BMI on mortality, and (though very imprecisely estimated) the NLMR suggested a lower /cont
Ultra-processed foods (UPFs) are apparently the new poison, and a recent @bmj_latest report by @rebeccacoombes suggests conflicts of interests in the “expert” views presented @smc_london that weren’t enthusiastic enough in promoting this notion. /contbmj.com/content/383/bm…
2/n Opposing these @DoctorChrisVT says there is “overwhelming evidence” of UPFs being harmful. The prospective studies (contrary to the quote, these were not “trials”, where people were randomised to higher or lower UPF consumption) do not show UPFs cause harm / cont
@DoctorChrisVT 3/n Their use is strongly patterned by socioeconomic position, health behaviours and other factors that would generate non-causal associations in such studies. Nor does the fact the studies were done @imperialcollege or adjust for some covariates. An equally large body / cont