Skip to content
By using Twitter’s services you agree to our Cookies Use. We and our partners operate globally and use cookies, including for analytics, personalisation, and ads.
  • Home Home Home, current page.
  • About

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
GidMK's profile
Health Nerd
Health Nerd
Health Nerd
Verified account
@GidMK

Tweets

Health NerdVerified account

@GidMK

Epidemiologist. Writer (Guardian, Observer etc). "Well known research trouble-maker". PhDing at @UoW Host of @senscipod Email gidmk.healthnerd@gmail.com he/him

Sydney, New South Wales
theguardian.com/profile/gideon…
Joined November 2015

Tweets

  • © 2021 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. Health Nerd‏Verified account @GidMK 25 Aug 2020

      A new study has come out that hit headlines everywhere arguing that there's no safe level of caffeine intake during pregnancy I think it's worth a bit of a peer-review on twitter 1/npic.twitter.com/2PdMhgDz05

      29 replies 221 retweets 664 likes
      Show this thread
    2. Health Nerd‏Verified account @GidMK 25 Aug 2020

      2/n I should at the outset say that I have a bit of skin in the game - I've previously looked at the evidence and argued that the harms at low levels of intake are not as worrying as they are often made out to be https://www.theguardian.com/commentisfree/2019/oct/17/is-drinking-coffee-safe-during-your-pregnancy-get-ready-for-some-nuance …pic.twitter.com/8SRus7JKA6

      3 replies 1 retweet 37 likes
      Show this thread
    3. Health Nerd‏Verified account @GidMK 25 Aug 2020

      3/n The study itself is here, in BMJ Evidence-Based Medicine:https://ebm.bmj.com/content/early/2020/07/28/bmjebm-2020-111432#DC1 …

      1 reply 0 retweets 29 likes
      Show this thread
    4. Health Nerd‏Verified account @GidMK 25 Aug 2020

      4/n The first problem comes right in the title - this is a 'narrative review' This is an issue because narrative reviews are generally not very good to rely on as proofpic.twitter.com/EHtw6b8k26

      2 replies 6 retweets 76 likes
      Show this thread
    5. Health Nerd‏Verified account @GidMK 25 Aug 2020

      5/n This is because of how they are conducted. Narrative reviews are, by nature, non-systematic reviews of the literature. In other words, they are 'expert opinion' level of data - they can inform, but it's hard to make conclusions based on them because of the methodology

      2 replies 3 retweets 62 likes
      Show this thread
    6. Health Nerd‏Verified account @GidMK 25 Aug 2020

      6/n We can see quite clearly why when we read the methodology here. This is the entire methods section - 1 paragraph! - and doesn't tell us NEARLY enough about how the included studies were foundpic.twitter.com/iqASzwCuJy

      2 replies 2 retweets 40 likes
      Show this thread
    7. Health Nerd‏Verified account @GidMK 25 Aug 2020

      7/n Were studies excluded? If so, why? Could the included studies simply be cherry-picked for the authors conclusions? What's the risk of publication bias, or other biases? We simply have no idea!

      2 replies 0 retweets 56 likes
      Show this thread
      Health Nerd‏Verified account @GidMK 25 Aug 2020

      8/n So right off the bat, we can't really say, from this study, much more than that this is one professor's expert opinion based on studies that they have identified

      7:21 PM - 25 Aug 2020
      • 43 Likes
      • Junior VP Rabbi Ruti Regan 🏳️‍🌈🇺🇸 Hawaiian Mega Punch🍹 Mela Eckenfels ANISH KAR Addleben Shuhiba Wajma Mohammad 🇦🇫 Jenn Aze
      1 reply 0 retweets 43 likes
        1. New conversation
        2. Health Nerd‏Verified account @GidMK 25 Aug 2020

          9/n Now, there's nothing wrong with that. Professors are smart, and often their opinions are very important But this isn't ~evidence~ in a scientific sense. The review says nothing new per se except that Prof James, Psychology, has this opinion based on studies he's readpic.twitter.com/H5hcUOuTd1

          2 replies 2 retweets 57 likes
          Show this thread
        3. Health Nerd‏Verified account @GidMK 25 Aug 2020

          10/n On to the included studies There are A LOT of them Kudos to the author for reading all of this literaturepic.twitter.com/fncBG0Ono6

          1 reply 0 retweets 28 likes
          Show this thread
        4. Health Nerd‏Verified account @GidMK 25 Aug 2020

          11/n Now, the problem is of course that to properly review a narrative review like this you would have to read every included piece of research, and with >40 studies to go through that's really quite a lot to do

          1 reply 1 retweet 23 likes
          Show this thread
        5. Health Nerd‏Verified account @GidMK 25 Aug 2020

          12/n But, even if you look at just a few, some issues emerge. The single biggest study on caffeine and miscarriage, for example In this review, it's cited as evidence that maternal caffeine consumption increases risk of miscarriagepic.twitter.com/CB0p6w4oSo

          1 reply 0 retweets 23 likes
          Show this thread
        6. Health Nerd‏Verified account @GidMK 25 Aug 2020

          13/n But actually, Gaskins et al found something a bit different. In their study, decaf coffee was associated with a higher risk and caffeinated tea was not Therefore, caffeine was NOT the likely culprit!pic.twitter.com/lHPzevG6MA

          2 replies 7 retweets 74 likes
          Show this thread
        7. Health Nerd‏Verified account @GidMK 25 Aug 2020

          14/n This gets to the heart of the issue with a narrative review. It is, essentially, the author's opinion of each study and what they mean - no systematizing, no group of authors carefully reading through each point to be careful

          1 reply 1 retweet 37 likes
          Show this thread
        8. Health Nerd‏Verified account @GidMK 25 Aug 2020

          15/n One person's evidence of the risk from caffeine is another person's evidence of safety Case in point - this systematic reviewpic.twitter.com/GJDfYXSyoT

          1 reply 0 retweets 25 likes
          Show this thread
        9. Health Nerd‏Verified account @GidMK 25 Aug 2020

          16/n In the narrative review, it's cited as evidence that any amount of caffeine is dangerous, but the authors actually concluded that their results were consistent with the WHO recommendation to limit caffeine consumption to <300mg per day during pregnancypic.twitter.com/SdnVZErUva

          1 reply 1 retweet 33 likes
          Show this thread
        10. Health Nerd‏Verified account @GidMK 25 Aug 2020

          17/n Similarly, the Greenwood et al meta-analysis is cited as evidence that even small amounts of caffeine are probably harmful, but the authors don't really agree!pic.twitter.com/2tmUUjXVMh

          1 reply 0 retweets 23 likes
          Show this thread
        11. Health Nerd‏Verified account @GidMK 25 Aug 2020

          18/n All of this is fine, and just the limitations of the narrative review. The entire purpose of such a document is to provide a narrative decided on by the author, which is neither good nor bad - it's just how these things work But that's not all of the issuespic.twitter.com/gV8iSLplzc

          1 reply 0 retweets 18 likes
          Show this thread
        12. Health Nerd‏Verified account @GidMK 25 Aug 2020

          19/ If you get to the last part of the paper, you'll see this table It contains a fundamental error that makes the numbers in the last column incorrectpic.twitter.com/3cQNOmY64R

          1 reply 0 retweets 20 likes
          Show this thread
        13. Health Nerd‏Verified account @GidMK 25 Aug 2020

          20/n This table is calculating the population attributable fraction of various pregnancy outcomes. The last column is the context - for the ~1 million miscarriages in the US each year, 280,000 are caused by caffeine! Shocking. And untruepic.twitter.com/irjABFVFwb

          1 reply 1 retweet 22 likes
          Show this thread
        14. Health Nerd‏Verified account @GidMK 25 Aug 2020

          21/n This table has several errors. The first is in column (i) This is cited as the risk per 100mg. In fact, it is the RELATIVE RISK INCREASE per ADDITIONAL 100mg of coffee consumedpic.twitter.com/GSrBhX27sf

          1 reply 1 retweet 36 likes
          Show this thread
        15. Health Nerd‏Verified account @GidMK 25 Aug 2020

          22/n This is then used to calculated the risk AT 200mg of miscarriage - double the risk at 100mg Except, this is incorrectpic.twitter.com/9qoYmqckYW

          1 reply 0 retweets 23 likes
          Show this thread
        16. Health Nerd‏Verified account @GidMK 25 Aug 2020

          23/n The BASELINE risk of miscarriage, for a woman who drinks NO coffee, is around 16%. The RELATIVE increase is 14% per 100mg of coffee. So the ABSOLUTE risk for a 200mg per day drinker is: 0.16*1.28 = .205 = 20.5% Thus, all the numbers in column (ii) are wrongpic.twitter.com/eZaChnR0Ls

          3 replies 5 retweets 30 likes
          Show this thread
        17. Health Nerd‏Verified account @GidMK 25 Aug 2020

          24/n The last column calculates the number of caffeine-related events by multiplying the risk in column (ii) with the total number in column (iv) So, 28% risk and 1 mil miscarriages means 280k miscarriages related to caffeinepic.twitter.com/JEqsAM7Q3A

          2 replies 0 retweets 17 likes
          Show this thread
        18. Health Nerd‏Verified account @GidMK 25 Aug 2020

          25/n Think about this for a second. Even if that number was correct - i.e. 20.5% rather than the wrong 28% - it doesn't make any sense because it assumes that 100% of women who have had miscarriages drank 200mg of caffeine a day

          1 reply 0 retweets 22 likes
          Show this thread
        19. Health Nerd‏Verified account @GidMK 25 Aug 2020

          26/n This number - called the Population Attributable Fraction (PAF) - is actually calculable. The formula is pretty simple:pic.twitter.com/eoTJ5euQVv

          1 reply 0 retweets 18 likes
          Show this thread
        20. Health Nerd‏Verified account @GidMK 25 Aug 2020

          27/n In this case, with a prevalence of ~35% for caffeine intake of 200mg or higher, the number of miscarriages attributable to this is: 0.35*(1-(1/1.28)) = 0.763 = ~76,300 miscarriages So, about a quarter of what's in this study

          2 replies 1 retweet 22 likes
          Show this thread
        21. Health Nerd‏Verified account @GidMK 25 Aug 2020

          28/n This actually makes perfect sense when you think about it. Remember, the ABSOLUTE risk increase of miscarriage for women who drink caffeine is pretty small - 1-2% - so it doesn't really make sense to say that up to a third of miscarriages are caused by caffeine

          1 reply 7 retweets 50 likes
          Show this thread
        22. Health Nerd‏Verified account @GidMK 25 Aug 2020

          29/n And yet, these figures were picked up in the media and thrown around as if certainly true, which is very worrying!pic.twitter.com/5v3SQPeKtn

          1 reply 0 retweets 28 likes
          Show this thread
        23. Health Nerd‏Verified account @GidMK 25 Aug 2020

          30/n More broadly speaking, do we know that caffeine causes bad pregnancy outcomes? That is a VERY tricky question to answer

          1 reply 1 retweet 21 likes
          Show this thread
        24. Health Nerd‏Verified account @GidMK 25 Aug 2020

          31/n This narrative review argues yes, absolutely, and while most people would agree a LOT of caffeine is a problem, much previous research has said that small amounts are probably not so badpic.twitter.com/50siPcJ8HD

          4 replies 1 retweet 24 likes
          Show this thread
        25. Health Nerd‏Verified account @GidMK 25 Aug 2020

          32/n This narrative review argues that all such studies are the product of industry funding, which is not entirely untrue, but also doesn't really tell the whole story given that it disagrees with non-industry studies as wellpic.twitter.com/ynC0gKO1nj

          1 reply 0 retweets 14 likes
          Show this thread
        26. Health Nerd‏Verified account @GidMK 25 Aug 2020

          33/n Ultimately, reviews like this come down to opinions Do we think that Prof James is correct and caffeine is definitely bad? Well, maybe. It depends on your perspective I think

          1 reply 0 retweets 14 likes
          Show this thread
        27. Health Nerd‏Verified account @GidMK 25 Aug 2020

          34/n What we can't say is that this is new evidence, or even that we've proven anything here. It's one well-researched opinion that you may or may not agree with 🤷‍♂️

          1 reply 1 retweet 19 likes
          Show this thread
        28. Health Nerd‏Verified account @GidMK 25 Aug 2020

          35/n Anyway, regardless of what you think of the review, it's probably worth correcting the inaccurate table @BMJ_EBM

          4 replies 2 retweets 48 likes
          Show this thread
        29. Health Nerd‏Verified account @GidMK 25 Aug 2020

          36/n Also, for the record, I think the conclusions are pretty massively overstated, and also miss out a key part of recommendations which is the question of whether they'll be followed!pic.twitter.com/uPDQfv4aHI

          3 replies 0 retweets 24 likes
          Show this thread
        30. Health Nerd‏Verified account @GidMK 26 Aug 2020

          37/n I should also say that I thoroughly dislike opinion pieces and media attention like this The evidence hasn't changed, and quite frankly I think pregnant people have enough to worry about without the fear that a cup of coffee will cause a miscarriage

          8 replies 9 retweets 98 likes
          Show this thread
        31. End of conversation

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2021 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Cookies
        • Ads info