Diabetes, Kids, and COVID

Emily Oster

7 min Read Emily Oster

Emily Oster

Diabetes, Kids, and COVID

Emily Oster

7 min Read
In early January, the CDC released, through its MMWR paper series, a report suggesting that kids under 18 who recovered from COVID-19 were at higher risk for developing diabetes. This was, predictably, widely covered in the media and led (for me, at least) to a long thread of panicked emails.

Online, a number of commentators picked at very significant limitations in the study. I agree; the study is extremely flawed. But it’s one thing to say that the study is problematic and another to unpack it and think about what might have been done differently. Which is what I want to do today. The TL;DR is that I do not see any compelling reason that the evidence should make you any more worried about this issue than you were before seeing the study.

I’ll talk it through in a few steps:

  1. What does the study do and say?
  2. What are the inherent problems and data limitations?
  3. What could it have done better?
  4. Why is this in the MMWR? Why did the CDC put it out?

What does the study do and say? 

You can read the MMWR study here. Very broadly, what the authors do is take two sources of medical claims data — this is data that reports diagnoses for individuals, based on insurance records — and explore the relationship between COVID-19 and the subsequent development of any type of diabetes in children.

More specifically: the authors identify patients who were diagnosed with COVID-19 at some point between March 2020 and February 2021. In one data set, this is based only on diagnosis; in the second it is also based on those with a positive COVID test. The authors then create an age-and-sex-matched comparison group of children who did not have a COVID-19 diagnosis during this period.

For the COVID-19 patients, the authors define the “index date” as the first date with a claim for COVID-19 or the first positive test. For the non-COVID patients, they choose a randomly selected claim date as the index date. They then analyze the number of diabetes diagnoses in the two groups in the months after the index date. This is a fairly common empirical approach, and it makes some intuitive sense. Basically, they want to ask whether a diabetes diagnosis is more common after a COVID-19 diagnosis than in another group after a randomly chosen non-COVID medical encounter.

What the authors find when they do this is that there are more diagnoses of diabetes in the month after the COVID-19 diagnosis than in the random following month in the non-COVID group. The overall numbers are small. For example, the authors find in the COVID-19 group an incidence of 316 diabetes diagnoses per 100,000 individuals per year. But the COVID-19 diagnosis group is consistently higher than the matched comparison group. The effects are more consistent for the 12-to-17 age group. And the authors show that this effect doesn’t show up if you look pre-COVID at other respiratory infections. That is, we do not see this effect after a flu diagnosis in 2018.

The diabetes diagnoses in the paper include both Type 1 and Type 2 diabetes, and the authors do not separate them out, so it is not possible to learn which type is driving these results.

The paper concludes that the data shows an increased risk of diabetes after COVID-19 infection for people under 18 and emphasizes the importance of vaccination.

What are the inherent problems and data limitations?

There are (at least) two important problems with this study. By far the most important is that the authors are unable to control for any characteristics of individuals other than age and sex.

To see why this is a problem, consider the issue of body mass index. Children vary in their BMI, and it is well-known that a higher BMI correlates with a greater chance of a Type 2 diabetes diagnosis. In addition, a higher BMI is also correlated with a greater risk of COVID-19 (not necessarily having it, but having a serious enough case for it to be detected). This latter point was made recently by the CDC in another MMWR piece.

What this means is that the population of children who have COVID-19 are more likely to have a higher BMI, and that higher BMI is associated with a greater risk of diabetes diagnosis. Even in the absence of COVID-19, they would be more likely to be diagnosed just given this risk factor.

Essentially, this is a problem of “residual confounding” or “omitted variable bias.” The two groups — the COVID and non-COVID group — are likely different in a number of ways that the authors do not adjust for. BMI is the most obvious, but others include race and socioeconomic status, as well as other conditions. Without this information, it is very difficult to know if COVID-19 is the cause of the higher rates of diabetes or if it is one of the many other differing factors.

There is a second issue, which relates to timing. Even if COVID-19 didn’t cause diabetes, we might see more diagnoses right after a diagnosis of COVID-19 because the sustained interaction with the medical system prompted diagnosis. Some of the checks the authors do make this story perhaps less likely, and I’d overall rank it as less important than the key issue of omitted variables.

The particular issue of not adjusting for BMI or obesity has been raised frequently in response to the paper. The reason the authors do not adjust for differences in this condition in their analysis is that they cannot do so with the data they have. The paper relies on medical claims data, which reports diagnosis codes but doesn’t have the kind of demographic or health data you’d get in (say) an electronic medical record. With data like this, it is simply not possible to adjust for differences in BMI or race or socioeconomic status.

This doesn’t mean they couldn’t have done better, though.

What could they have done better?

What the authors have to work with here is a long “time series” of data on individuals and diagnosis codes. With this, they could do better than they did.

One improvement to the paper would be to separate out Type 1 and Type 2 diagnoses. These have different diagnosis codes, so it is possible to look at them separately. I am not sure why that wasn’t done.

A second improvement would be to adjust for pre-diabetes. Often, with Type 2 diabetes, individuals are diagnosed with “pre-diabetes” prior to diabetes diagnosis. It’s a diagnosis that comes with some behavior-change advice and perhaps additional monitoring. There is a diagnosis code for pre-diabetes, and the authors could have used that to look at differences across groups, or as a control.

A more involved but more useful improvement would have been to use more of the time variation in the data to, effectively, look for pre-trends. To see how this works, let’s go back to the basics of their approach. The authors have a COVID-19 group and a comparison group, and they compare diabetes diagnosis rates in the month after COVID-19. If they were to put their results on a graph, it would be like this:

But the reality is that they have data from the earlier and later periods that they are not using. It would be possible to, for these same people, look at diagnosis rates earlier and later.1 Why would this be helpful? Let’s think about the graph below, where I’ve added two sets of lines, both of which would be consistent with the data in the paper.

The solid lines — light blue versus dark blue — reflect what looks like a real effect of COVID-19 on diagnosis. Most importantly, the diagnosis rates in the earlier period are similar, and it is only post-COVID that the rates go up. The dotted lines, though, would also be consistent with the numbers in the paper, but they tell a totally different story. They would tell a story of two groups with different underlying risks but where COVID seemed to play little role.

I do not know which graph would show up if the authors had done this. It wouldn’t be hard to do. My strong suspicion is it would look more like the dotted lines than the solid ones. But that is just my instinct. My point isn’t that we can prove that the results are biased in this way; it is, instead, that the paper could have been done better.

In the end, that is my strongest feeling in reading it. This paper is about a possibly important question, and in principle the data seems like it could be informative (up to a point). But the paper isn’t well-done. It’s missing very basic analysis, like separating out Type 1 and Type 2 diabetes. Graphing diagnoses over time isn’t a magical approach I made up for this newsletter; it’s standard for an event. The idea of using other suggestive diagnoses like pre-diabetes for controls is straightforward. There are a tremendous number of fillable holes.

The holes ultimately add up to the point where the paper isn’t informative. Could it be that there is an effect? There could, just like there could have been before you saw the article. But I would say I’m no more convinced of an effect after reading the paper than before, which isn’t a great commentary.

Why is this in MMWR?

I suspect the question has occurred to many of you in reading this: Why is it in MMWR? The outlet has gotten a huge amount of attention during the pandemic, and this particular article was widely covered in major media outlets. I’m far from the only person to notice its glaring weaknesses.

Why weren’t these issues caught in peer review? The goal of peer review, in an ideal world, is to identify basic weaknesses and ask the authors to fix them. The main answer is that MMWR isn’t peer-reviewed, at least not in the traditional sense. Papers undergo a 14-step review process that takes months, but the review is all internal to the CDC. In my experience from publishing there, much of this review focuses on format and phrasing and not on the content of the analysis.

MMWR publications are also an opportunity to put scientific weight behind public health messaging. In this case, the paper ends with a strong push for vaccination for children, a message that the CDC has been trying to send in many ways. I am also strongly supportive of vaccination for children, but there are much better ways to convince people (like this chart about vaccination and hospitalization in New York State).

It’s actually not helpful to try to convince people to vaccinate their kids with poor quality evidence of this type. It gives those who oppose vaccines something legitimate to complain about, and terrifies at least some parents whose kids are not vaccine eligible yet.

I am not sure why this paper was selected for MMWR or what type of review it went through. What I can say is that the paper is deeply flawed, and if you are worrying about it, you should stop.

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Updated CDC Guidelines for School and Child Care

NO QUARANTINES!!!

Emily Oster

Instagram

left right
The AAP’s guidelines recommend sleeping in the same room as your baby “ideally for the first six months.” However, the risk of SIDS is dramatically lower after four months, and the evidence in favor of the protective effect of room sharing is quite weak (both overall and even more so after four months). There is also growing evidence that infants who sleep in their own room by four months sleep better at four months, better at nine months, and even better at 30 months.

With this in mind, it’s worth asking why this recommendation continues at all — or at least why the AAP doesn’t push it back to four months. They say decreased arousals from sleep are linked to SIDS, which could mean that babies sleeping in their own room is risky. But this link is extremely indirect, and they do not show direct evidence to support it.

According to the data we have, parents should sleep in the same room as a baby for as long as it works for them! Sharing a room with a child may have negative impacts on both child and adult sleep. We should give families more help in navigating these trade-offs and making the decisions that work best for them.

#emilyoster #parentdata #roomsharing #sids #parentingguide

The AAP’s guidelines recommend sleeping in the same room as your baby “ideally for the first six months.” However, the risk of SIDS is dramatically lower after four months, and the evidence in favor of the protective effect of room sharing is quite weak (both overall and even more so after four months). There is also growing evidence that infants who sleep in their own room by four months sleep better at four months, better at nine months, and even better at 30 months.

With this in mind, it’s worth asking why this recommendation continues at all — or at least why the AAP doesn’t push it back to four months. They say decreased arousals from sleep are linked to SIDS, which could mean that babies sleeping in their own room is risky. But this link is extremely indirect, and they do not show direct evidence to support it.

According to the data we have, parents should sleep in the same room as a baby for as long as it works for them! Sharing a room with a child may have negative impacts on both child and adult sleep. We should give families more help in navigating these trade-offs and making the decisions that work best for them.

#emilyoster #parentdata #roomsharing #sids #parentingguide
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It was an absolute pleasure to be featured on the @tamronhallshow! We talked about all things data-driven parenting and, in this clip, what I call the plague of secret parenting. To balance having a career and having a family, we can’t hide the fact that we’re parents. If mothers and fathers at the top can speak more openly about child-care obligations, it will help us all set a new precedent.

Watch the full segment at the link in my bio 🔗

#tamronhall #tamronhallshow #emilyoster #parentingsupport #workingparents

It was an absolute pleasure to be featured on the @tamronhallshow! We talked about all things data-driven parenting and, in this clip, what I call the plague of secret parenting. To balance having a career and having a family, we can’t hide the fact that we’re parents. If mothers and fathers at the top can speak more openly about child-care obligations, it will help us all set a new precedent.

Watch the full segment at the link in my bio 🔗

#tamronhall #tamronhallshow #emilyoster #parentingsupport #workingparents
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Invisible labor. It’s the work — in our households especially — that has to happen but that no one sees. It’s making the doctor’s appointment, ensuring birthday cards are purchased, remembering the milk.

My guest on this episode, @everodsky, has come up with a solution here, or at least a way for us to recognize the problem and make our own solutions. I’ve wanted to speak with Eve for ages, since I read her book Fair Play. We had a great conversation about the division of household labor, one I think you’ll get a lot out of!

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#emilyoster #parentdata #parentdatapodcast #parentingpodcast #householdtips #fairplay #invisiblelabor

Invisible labor. It’s the work — in our households especially — that has to happen but that no one sees. It’s making the doctor’s appointment, ensuring birthday cards are purchased, remembering the milk.

My guest on this episode, @everodsky, has come up with a solution here, or at least a way for us to recognize the problem and make our own solutions. I’ve wanted to speak with Eve for ages, since I read her book Fair Play. We had a great conversation about the division of household labor, one I think you’ll get a lot out of!

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#emilyoster #parentdata #parentdatapodcast #parentingpodcast #householdtips #fairplay #invisiblelabor
...

Prenatal vitamins 💊 If there is any product that seems designed to prey on our fears, it’s this one. You’re newly pregnant and you want to do it right. Everyone agrees you need prenatal vitamins, so you get them. But do you want to be that person who just… buys the generic prenatal vitamins?

Good news: fancier vitamins are not better.  Folic acid is the most important prenatal ingredient. Iron (with vitamin C) and DHA are also nice to have. Other included ingredients have only weak or no evidence to support their use. (If you do not consume animal products, add B12, plus a few others depending on your diet.)

Vitamins are just vitamins. Any prenatal vitamin that contains these is enough. 

Comment “Link” for a DM to an article with everything you need to know about prenatal vitamins.

#emilyoster #parentdata #prenatalvitamins #pregnancydiet #pregnancytips

Prenatal vitamins 💊 If there is any product that seems designed to prey on our fears, it’s this one. You’re newly pregnant and you want to do it right. Everyone agrees you need prenatal vitamins, so you get them. But do you want to be that person who just… buys the generic prenatal vitamins?

Good news: fancier vitamins are not better. Folic acid is the most important prenatal ingredient. Iron (with vitamin C) and DHA are also nice to have. Other included ingredients have only weak or no evidence to support their use. (If you do not consume animal products, add B12, plus a few others depending on your diet.)

Vitamins are just vitamins. Any prenatal vitamin that contains these is enough.

Comment “Link” for a DM to an article with everything you need to know about prenatal vitamins.

#emilyoster #parentdata #prenatalvitamins #pregnancydiet #pregnancytips
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When it comes to introducing your newborn to the world, timing matters. It’s a good idea to minimize germ exposure in the first 6-8 weeks; after that, it’s inevitable and, very likely, a good idea! This doesn’t mean you need to be trapped inside. The most significant exposure risks are from seeing other people at home — family, etc. These interactions are not infinitely risky, but they do pose more risk than a walk or a trip to the grocery store, since they involve closer interaction. Think simple and make sure everyone is washing their hands before holding the baby. 💛

#parentdata #emilyoster #newborncare #parentingadvice #parentingtips

When it comes to introducing your newborn to the world, timing matters. It’s a good idea to minimize germ exposure in the first 6-8 weeks; after that, it’s inevitable and, very likely, a good idea! This doesn’t mean you need to be trapped inside. The most significant exposure risks are from seeing other people at home — family, etc. These interactions are not infinitely risky, but they do pose more risk than a walk or a trip to the grocery store, since they involve closer interaction. Think simple and make sure everyone is washing their hands before holding the baby. 💛

#parentdata #emilyoster #newborncare #parentingadvice #parentingtips
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The first edition of Hot Flash is out now! Comment “Link” for a DM to learn more about the late-reproductive stage.

There are times when we expect hormonal shifts. Our reproductive lives are bookended by puberty and menopause. We discuss those changes often because they are definitive and dramatic — a first period is something many of us remember clearly. But between ages 13 and 53, our hormones are changing in more subtle ways. During the late-reproductive stage (in your 40s), you can expect a lot of changes in your menstrual cycle, including the length and symptoms you experience throughout. It’s an important time in our lives that is often overlooked!

🔥 Hot Flash from ParentData is a weekly newsletter on navigating your health and hormones in the post-reproductive years. Written by Dr. Gillian Goddard, Hot Flash provides all of the information you need to have a productive, evidence-based conversation about hormonal health with your doctor.

#emilyoster #parentdata #hotflash #perimenopause #womenshealth

The first edition of Hot Flash is out now! Comment “Link” for a DM to learn more about the late-reproductive stage.

There are times when we expect hormonal shifts. Our reproductive lives are bookended by puberty and menopause. We discuss those changes often because they are definitive and dramatic — a first period is something many of us remember clearly. But between ages 13 and 53, our hormones are changing in more subtle ways. During the late-reproductive stage (in your 40s), you can expect a lot of changes in your menstrual cycle, including the length and symptoms you experience throughout. It’s an important time in our lives that is often overlooked!

🔥 Hot Flash from ParentData is a weekly newsletter on navigating your health and hormones in the post-reproductive years. Written by Dr. Gillian Goddard, Hot Flash provides all of the information you need to have a productive, evidence-based conversation about hormonal health with your doctor.

#emilyoster #parentdata #hotflash #perimenopause #womenshealth
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There are plenty of reels telling you how to parent. Plenty of panic headlines saying that “studies show” what’s best for your kid. Even good data, from a trusted source, can send us into a spiral of comparison. But I want you to remember that no one knows your kid better than you. It’s important to absorb the research, but only you will know the approach that works best for you and your child. 💙

Now tell me in the comments: what’s a parenting move you’ve made recently that feels right to you?

#parentingcommunity #parentingsupport #parentingquotes #emilyoster #parentdata

There are plenty of reels telling you how to parent. Plenty of panic headlines saying that “studies show” what’s best for your kid. Even good data, from a trusted source, can send us into a spiral of comparison. But I want you to remember that no one knows your kid better than you. It’s important to absorb the research, but only you will know the approach that works best for you and your child. 💙

Now tell me in the comments: what’s a parenting move you’ve made recently that feels right to you?

#parentingcommunity #parentingsupport #parentingquotes #emilyoster #parentdata
...

Let’s talk about sex (after) baby! Today on the podcast, I was lucky enough to speak with @enagoski about her new book on sexual connection in long-term relationships. Especially after having kids, this is something many people struggle with. Emily tells us to stop worrying about what’s “normal” and focus on pleasure in its many forms.

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#parentdata #parentdatapodcast #emilyoster #emilynagoski #comeasyouare #cometogether #longtermrelationship #intimacy #relationships

Let’s talk about sex (after) baby! Today on the podcast, I was lucky enough to speak with @enagoski about her new book on sexual connection in long-term relationships. Especially after having kids, this is something many people struggle with. Emily tells us to stop worrying about what’s “normal” and focus on pleasure in its many forms.

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#parentdata #parentdatapodcast #emilyoster #emilynagoski #comeasyouare #cometogether #longtermrelationship #intimacy #relationships
...

Ever wondered if you can safely use leftover baby formula? 🍼 The CDC says to throw out unused formula immediately because of the risk of bacterial growth. However, research suggests that bacterial concentrations do not appreciably increase after 3, 12, or even 24 hours at refrigerator temperatures. Good news! This means there’s not a strong data-based reason to throw out formula right away if you store it in the fridge.

Comment “Link” for a DM to an article on another common formula question: should you throw away old formula powder?

#emilyoster #parentdata #babyformula #babyfeeding #parentingstruggles

Ever wondered if you can safely use leftover baby formula? 🍼 The CDC says to throw out unused formula immediately because of the risk of bacterial growth. However, research suggests that bacterial concentrations do not appreciably increase after 3, 12, or even 24 hours at refrigerator temperatures. Good news! This means there’s not a strong data-based reason to throw out formula right away if you store it in the fridge.

Comment “Link” for a DM to an article on another common formula question: should you throw away old formula powder?

#emilyoster #parentdata #babyformula #babyfeeding #parentingstruggles
...

What’s the most important piece of advice for new parents? Here’s one answer, but I want to hear from you! Share your suggestions in the comments ⬇️

#emilyoster #parentdata #parentingtips #parentingadvice #newparents #parentingcommunity

What’s the most important piece of advice for new parents? Here’s one answer, but I want to hear from you! Share your suggestions in the comments ⬇️

#emilyoster #parentdata #parentingtips #parentingadvice #newparents #parentingcommunity
...

What's in the bag of a Vagina Economist? 👀 Someone please tell me this looks familiar to you.

What`s in the bag of a Vagina Economist? 👀 Someone please tell me this looks familiar to you. ...

Comment ”link” for a DM to learn more about tongue ties 🔗

Breastfeeding is often difficult, especially at the start. For babies with tongue ties, many infants (and their moms) struggle to get the hang of a good latch. This can lead to painful nipples and to inefficient feeding, and then low weight gain.

So what does the data say about the increasingly common practice of cutting tongue-ties in infants to improve breastfeeding success? Several weeks ago, @nytimes published a long and quite scary article on this topic.

After diving into the data, here is what I found. There is limited evidence that frenotomy procedures improve breastfeeding efficacy and the harms of the procedure are minimal. Many women do report that it alleviates pain and helps them with breastfeeding. However, it should not be a first-line treatment for breastfeeding problems.

#parentdata #emilyoster #tonguetie #tonguetiebabies #breastfeedingsupport

Comment ”link” for a DM to learn more about tongue ties 🔗

Breastfeeding is often difficult, especially at the start. For babies with tongue ties, many infants (and their moms) struggle to get the hang of a good latch. This can lead to painful nipples and to inefficient feeding, and then low weight gain.

So what does the data say about the increasingly common practice of cutting tongue-ties in infants to improve breastfeeding success? Several weeks ago, @nytimes published a long and quite scary article on this topic.

After diving into the data, here is what I found. There is limited evidence that frenotomy procedures improve breastfeeding efficacy and the harms of the procedure are minimal. Many women do report that it alleviates pain and helps them with breastfeeding. However, it should not be a first-line treatment for breastfeeding problems.

#parentdata #emilyoster #tonguetie #tonguetiebabies #breastfeedingsupport
...

Tag a friend who needs to hear this 💛 For many choices in parenting, there is no one right answer. We can use research and data to make informed decisions, but ultimately, it won’t tell you what to do. Only you can decide what will be best for your kids and your family.

I’m here to remind you to take a deep breath and trust yourself. I’ll be here to support you along the way. 

Thank you to everyone who submitted videos, including:
@sarah.consoli
@jess_lynn627
@nicolevandenwills
@thedrblair
@ncbenedict29
@haleycimini
@iamkellysnodgrass
@calesse_smith
@garnet__gordon
@jencoopgaiser87
@danigirl18c
@jamielundergreen
@carly_comber
@thecelebratingmama
@emilyannbynum
@eeliz413

#emilyoster #parentdata #parentingadvice #parentingsupport #parentingquotes

Tag a friend who needs to hear this 💛 For many choices in parenting, there is no one right answer. We can use research and data to make informed decisions, but ultimately, it won’t tell you what to do. Only you can decide what will be best for your kids and your family.

I’m here to remind you to take a deep breath and trust yourself. I’ll be here to support you along the way.

Thank you to everyone who submitted videos, including:
@sarah.consoli
@jess_lynn627
@nicolevandenwills
@thedrblair
@ncbenedict29
@haleycimini
@iamkellysnodgrass
@calesse_smith
@garnet__gordon
@jencoopgaiser87
@danigirl18c
@jamielundergreen
@carly_comber
@thecelebratingmama
@emilyannbynum
@eeliz413

#emilyoster #parentdata #parentingadvice #parentingsupport #parentingquotes
...

Congratulations on making it through another year of panic headlines! We’ve had some doozies this year, like aspartame causing cancer and the perils of white noise, but these headlines are very often based on poor data. Correlation does not equal causation. There will certainly be more panic headlines in 2024, but ParentData is here to debunk them for you.

#emilyoster #parentdata #happynewyear2024 #panicheadline #datadriven

Congratulations on making it through another year of panic headlines! We’ve had some doozies this year, like aspartame causing cancer and the perils of white noise, but these headlines are very often based on poor data. Correlation does not equal causation. There will certainly be more panic headlines in 2024, but ParentData is here to debunk them for you.

#emilyoster #parentdata #happynewyear2024 #panicheadline #datadriven
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