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George Davey Smith

@mendelrandom.bsky.social
1.4K followers 198 following 162 posts

Time expired epidemiologist

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Reposted by George Davey Smith
Society for Social Medicine & Population Health @socsocmed.bsky.social · 10/09/2026
Thank you to our excellent International Epidemiological Association plenary panellists for sharing their reflections on Jørn Olsen's career for the future of epidemiology! Some of their final reflections (possibly slightly paraphrased!):
George Davey-Smith speaking on stage during our IEA panel Katrine Strandberg-Larsen speaking on stage during our IEA panel Henrique Barros speaking on stage during our IEA panel
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Count Binface @countbinface.bsky.social · 27/07/2026
Here it is. My manifesto for the 2026 Clacton By-Election. It's a once-in-a-lifetime opportunity. Join me, clean up Clacton and let's make 13th August Bin Day! #VoteBinface #VoteyMcVoteface #YesWeTinCan
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George Davey Smith @mendelrandom.bsky.social · 23/07/2026
I enjoyed giving the annual "distinguished lecture" on triangulation of evidence / the variety of evidence thesis @cam.ac.uk Medical school, particularly as I could remind them at the beginning that they had tried to throw me out when I was a clinical medical student there youtu.be/e2ttItEnwCU
youtu.be
Distinguished Lecture: Evidence triangulation: moving from correlations to causes
YouTube video by MRC IEU at University of Bristol
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George Davey Smith @mendelrandom.bsky.social · 23/07/2026
Looking forward to visiting @humantechnopole.bsky.social to discuss triangulation and meeting some of the fantastic faculty and researchers working there
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
16/16 Paper here: medrxiv.org/content/10.6... Real team effort from @imperialcollegeldn.bsky.social Standford Uni @uob-ieu.bsky.social @princeton.edu @ukdri.ac.uk and many others I didn't tag. I present the data here: youtube.com/watch?v=qlTnnQ
medrxiv.org
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
15/n a study reflect a choice. In summary, we don't see an effect on hospital coded dementia. we don't think this is because of our data, analytic method, or approach. This does not rule out a small effect (but the effect size would be smaller than that reported as point estimates previously) /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
14/n There are *many* ways to do RD - numerous packages; numerous estimators; many other choices. Many of these are very reasonable! However, these seem to make tangible differences, and these are likely larger in smaller studies (because of more sampling variation). The results reported from /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
13/n We don't have an easy explanation for these differences. We discuss in the paper a lot more, but one explanation is - that RD designs - like all observational designs - have more analytic choices than RCTs, which means results are often more variable than an ITT RCT /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
12/n ascertainment issues in hospital data, and sampling variation, these results are plausibly both consistent with a small effect. However, our result is not consistent with the Australian (JAMA, 2025), or Ontario (Lancet Neuro (2026) data, which have *much* larger effects. /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
11/n Our result is not entirely consistent with the prior literature. In Wales, Eyting reported a 1.3% absolute risk reduction (95% CI 0.2-2.7), so although our confidence intervals overlap, our point estimate of 0.06 sits outside their CI (as does theirs to ours). However, given /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
10/n So in summary: none of the candidate biases we tested in our data would manufacture a null result from an effect the scale of which was observed in Wales. We also provide some mathematical discussion of the plausibility of some of these potential biases /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
9/n We then tested whether their result would stand if in Wales they only had hospital data, if they had the same study entry as us, etc: essentially we tested many of the biases of HES. Essentially, these decisions have an effect on absolute effects but NOT relative effects /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
8/n Our outcome is hospital coded dementia. We have no linked mortality or primary care data. Is this an issue? We went back to the Wales data where the protective signal was originally reported (nature.com/articles/s41...) and replicated their key finding on dementia (using their code) /cont
nature.com
A natural experiment on the effect of herpes zoster vaccination on dementia - Nature
Using a natural experiment that avoids common bias concerns, this study finds that the live-attenuated shingles vaccine reduced the probability of a new dementia diagnosis within a follow-up period of...
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
7/n To test this, we limited our analyses to those who were plausibly vaccinated (e.g. only those 79+), and started follow up at 1 year post Sep 2013 (this would give ~6 months for the vaccine to work). This analysis was null /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
6/n We don't see any sex-specific effects for either shingles or dementia, unlike what has been previously reported for dementia. The *only* signal we saw was a very early signal at 1 year. This signal is probably implausible, because shingles vaccination doesn't happen instantly /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
5/n Importantly, we replicated this in an *independent* extract from the same dataset, analysed by a different team at Imperial College London, with a different data granularity (week vs month) and with a different inclusion lookback period. This is reassuring! /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
4/n But we find *no* effect on dementia hospitalisations: −0.06 percentage points, 95% CI −0.40 to 0.27; p=0.72. The confidence intervals are reasonably tight on the absolute scale; and visually ⬇️ one cannot see any discontinuity. This was robust in many sensitivity analyses /cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
3/n First, we show a robust effect on shingles diagnoses using this date of birth cut off - this accumulates over and is about the same relative effect as reported in the trials. Importantly, this is *hospital* coded shingles - which is ~10% of all shingles, so the outcome is rare. / cont
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
2/n This design takes advantage of the quasi randomisation afforded by date of birth eligibility for the live attenuated shingles vaccine where in Sep 2013 80+ year olds never got it but 79 year olds did get it. We can then compare these two groups and see! www.medrxiv.org/content/10.6... /cont
medrxiv.org
Eligibility for shingles vaccination and hospital-coded dementia in England and Wales: a regression discontinuity analysis in England
We used the September 2013 age-based rollout of the live-attenuated shingles vaccine in England as a natural experiment to estimate the effect of vaccine eligibility on shingles and dementia diagnoses...
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George Davey Smith @mendelrandom.bsky.social · 22/07/2026
Does the (live) shingles vaccine protect against dementia? Fergus Hamilton and colleagues provide important evidence in a new preprint using hospital data from the whole of England in a regression discontinuity design from which we *don't* show evidence of a meaningful protective effect /cont
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George Davey Smith @mendelrandom.bsky.social · 15/07/2026
Yeah .. the replication crisis and all that …
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George Davey Smith @mendelrandom.bsky.social · 15/07/2026
It was in the xmas BMJ - make of that what you will
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George Davey Smith @mendelrandom.bsky.social · 15/07/2026
With England vs Argentina in the world cup don’t get too excited if it gets to a penalty shoot out .. here an analysis of the 1998 shoot out vs Argentina using regression discontinuity shows increase in heart attacks pubmed.ncbi.nlm.nih.gov/12493655/
pubmed.ncbi.nlm.nih.gov
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George Davey Smith @mendelrandom.bsky.social · 15/07/2026
With England vs Argentina in the world cup don’t get too excited if it gets to a penalty shoot out .. here an analysis of the 1998 shoot out vs Argentina using regression discontinuity shows increase in heart attacks pubmed.ncbi.nlm.nih.gov/12493655/
pubmed.ncbi.nlm.nih.gov
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George Davey Smith @mendelrandom.bsky.social · 14/07/2026
"We hold these truths to be self-evident, that science flourishes when based on reliable evidence and rigorous testing" @royalsociety.org great response to US Office of Management and Budget latest anti-internationalist anti-science moves has a familiar ring to it? royalsociety.org/news/2026/07...
royalsociety.org
Response to the consultation on the “Regulation for Federal Financial Assistance” proposed by the US Office of Management and Budget | Royal Society
Sir Paul Nurse, President of the Royal Society, responds to the “Regulation for Federal Financial Assistance” proposed by the US Office of Management and Budget.
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George Davey Smith @mendelrandom.bsky.social · 14/07/2026
can't face reading it .. does it contain the "attending religious services makes you live longer, get less cancer, less heart disease and get murdered less" stuff?
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Darren Dahly @statsepi.bsky.social · 13/07/2026
Everyone is entitled to their opinion, and this essay by Johnson and VanderWeele is no exception. Just like I'm entitled to my opinion that this is one of the dumbest fucking things I've ever read. ajph.aphapublications.org/doi/epdf/10....
ajph.aphapublications.org
AJPH
American Journal of Public Health (AJPH) from the American Public Health Association (APHA)
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George Davey Smith @mendelrandom.bsky.social · 13/07/2026
Keir Starmer and Alexander Kerensky: compare and contrast in 300 characters. Win the most banal Ted Talk of all time
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George Davey Smith @mendelrandom.bsky.social · 13/07/2026
Read this academic.oup.com/ije/article/... will convert boredom to soothing sleep
academic.oup.com
Epigenesis for epidemiologists: does evo-devo have implications for population health research and practice?
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George Davey Smith @mendelrandom.bsky.social · 28/06/2026
I agree re: HRT, breast cancer matches up, but CHD very different, & I’m not a fan of the attempt to reconcile the two. It’s a huge missed opportunity that those with the data from the studies that suggested eg vitamin E supplements wd reduce CHD by 40% haven’t studied why they got it so wrong
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Alasdair Munro @apsmunro.bsky.social · 23/06/2026
Completely agree I’ve written about the saga here ( @mendelrandom.bsky.social was kind enough to give me his input before I published!) Like the findings? Then limitations don’t matter! It’s now a fact!
open.substack.com
The truth about the shingles vaccine and dementia
Ground breaking intervention or senseless hype?
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George Davey Smith @mendelrandom.bsky.social · 19/06/2026
no, you have to suffer for 55 mins to get the answer ... but just think how long I suffered to generate it 🤣
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Ben Recht @beenwrekt.bsky.social · 18/06/2026
Link to a great talk by @mendelrandom.bsky.social presenting new work that finds no effect.
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George Davey Smith @mendelrandom.bsky.social · 18/06/2026
How strong is the evidence that live shingles vaccination prevents the risk of dementia? A talk yesterday @oxprimarycare.bsky.social on this available here youtu.be/qlTnnQytOJ0
youtu.be
Guest Lecture 17 June 2026, does the shingles vaccine prevent dementia?
YouTube video by Nuffield Department of Primary Care Health Science
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George Davey Smith @mendelrandom.bsky.social · 15/06/2026
🤣 🤣 🤣
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George Davey Smith @mendelrandom.bsky.social · 15/06/2026
Much interest (and hope) invested in whether shingles vaccination can reduce dementia risk, but what does the evidence actually show? I'll be presenting some new analyses virtually (and in person in Oxford) at 12.15pm UK time 17th July (free registration) events.ox.ac.uk/oxford_event...
events.ox.ac.uk
Oxford Events
Oxford research division site
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Tom Yates @tomayates.bsky.social · 04/06/2026
Missed this nice commentary from @gushamilton.bsky.social and @mendelrandom.bsky.social - lots of food for thought for someone thinking of dipping their toe into some infection genetic epi ...
pubmed.ncbi.nlm.nih.gov
Mendelian Randomization and Infection: Pitfalls and Promises - PubMed
Mendelian randomization (MR) is an increasingly common study design in infectious diseases (ID). It holds promise for identifying causes and consequences of infections where conventional epidemiology ...
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George Davey Smith @mendelrandom.bsky.social · 07/05/2026
.... although in truth when there isn't a photographer about some of us push our bikes slowly up the hills ...
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Stephen Senn @stephensenn.bsky.social · 01/05/2026
Should be good. It seems that July will be randomisation month this year. rss.org.uk/training-eve... 100 years ago Fisher wrote this: repository.rothamsted.ac.uk/id/eprint/20...
rss.org.uk
Discussion paper meetings
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George Davey Smith @mendelrandom.bsky.social · 01/05/2026
If you're interested in the history and philosophy of randomization in all its forms I'm co-organising a *FREE* conference in glorious Bristol 2-3rd July wth the legendary Samir Okasha, registration is here www.eventbrite.co.uk/e/randomizat... If you think it looks interesting please advertise
eventbrite.co.uk
Randomization in Science, Society and Nature
Exploring the role of randomization across decision theory, clinical trials, politics, evolutionary biology and genetics
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George Davey Smith @mendelrandom.bsky.social · 16/04/2026
2/2 which are often high ranking ones - have published papers they must know are complete nonsense, but neither the journals, nor the authors or methods promoters are actively helping in stemming the tide of this rubbish. For more on this see academic.oup.com/ije/article/...
academic.oup.com
Erroneous epidemiological findings on vitamins: coming full circle after two decades of Mendelian randomization?
Our editorial responsibility for the International Journal of Epidemiology (IJE) started at the dawn of the current millennium, and we marked the occasion
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George Davey Smith @mendelrandom.bsky.social · 16/04/2026
Yet another spurious non-linear Mendelian randomization paper has been retracted by a journal academic.oup.com/jpubhealth/a... Kudos to the editors of the Journal of Public Health for following through and retracting spurious publications. What is shocking is that many other journals /cont
academic.oup.com
Retraction of: Association between Vitamin D and mortality risk in gout patients
This is a retraction of: Xinyu Fang, Jie Zhang, Zixing Zhang, Dongqing Ye. Association between Vitamin D and mortality risk in gout patients, Journal of Pu
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Cristian Pattaro @cpattaro.bsky.social · 18/03/2026
G-EE A very much needed (and brilliant) reflection for Mendelian randomization
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George Davey Smith @mendelrandom.bsky.social · 28/03/2026
Have seen thousands of Velvets covers and also saw the Velvet Underground be their own tribute band on two unforgettable nights at Edinburgh playhouse June 1993, but think Waldo’s Gift at Ritual Union 2026 Bristol got closer to the VU spirit than any others I’ve seen
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George Davey Smith @mendelrandom.bsky.social · 28/03/2026
Blog by Andrew Elmore on the genotype-phenotype map reaource ieureka.blogs.bristol.ac.uk/2026/03/11/g...
ieureka.blogs.bristol.ac.uk
A Guide to The Genotype-Phenotype Map – IEUREKA!
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George Davey Smith @mendelrandom.bsky.social · 19/03/2026
🙏
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George Davey Smith @mendelrandom.bsky.social · 18/03/2026
🙏
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George Davey Smith @mendelrandom.bsky.social · 18/03/2026
I get confused and have to remind myself that despite my email address up till 2009 being zetkin@BLAH (depending where I was) this is Mel!
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George Davey Smith @mendelrandom.bsky.social · 18/03/2026
the principle for understanding genetic effects being that of gene-environment equivalence journals.plos.org/plosmedicine...
journals.plos.org
Gene-environment equivalence: The fundamental principle of Mendelian randomization
In this Perspective, George Davey Smith and colleagues outline how and why gene-environment equivalence, the fundamental principle of Mendelian Randomization (MR), must be properly applied and critica...
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George Davey Smith @mendelrandom.bsky.social · 18/03/2026
A comprehensive new tool for exploring how genetic variation influences outcomes, of relevance to everything driven by phenotypes, which encapsulates many domains, from how drugs work to how natural selection works ... / cont
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