Adverse Reactions
An interview podcast bringing you the people and stories behind the science of how biological, physical, and chemical agents may cause adverse reactions to public, animal, and environmental health. This podcast is presented by the Society of Toxicology (SOT) and hosted by SOT members Anne Chappelle and David Faulkner.
About Anne
After graduating from the University of Delaware with a BS in biology in 1991, Anne Chappelle accidentally found her calling when she worked a gap year in an industrial toxicology laboratory. As it turned out, toxicology was the perfect marriage of protecting both human health and the environment. She then went on to receive her PhD in pharmacology and toxicology from the (now) University of the Sciences in Philadelphia in 1997, focusing on upper respiratory tract toxicity.
For the last 20+ years, as a toxicologist and risk assessment expert for the chemical industry, Anne has been thrilled to not work in a laboratory anymore. Along the way, she has added a few more titles: spouse; DABT; Principal of Chappelle Toxicology Consulting, LLC; occasional blogger at My Toxic Life; and most life changing (and expensive): Mom. She is thrilled to be partnered with David to add podcast co-host to the list because it gives her the opportunity to “channel my inner Terry Gross.”
About David
David Faulkner’s interest in science started at age five with a few Bill Nye the Science Guy VHS tapes and hasn’t diminished since. A lifelong artist and science fan, David has worked in nearly every mass communication medium to share his love of science with the world. Now, as an early career toxicologist, David is living out his dream of co-hosting a science podcast! With a budget! And a producer! And super cool guests! And an awesome co-host! David thinks Bill would be proud.
David attended the University of Michigan, where he completed a BS in microbiology, a BA in English language (emphasis in creative writing), and an MPH in environmental health sciences, and the University of California Berkeley, where he completed a PhD in molecular toxicology under the supervision of Dr. Chris Vulpe. He has held postdoctoral appointments at the Berkeley Center for Green Chemistry and the Lawrence Berkeley National Laboratory and just started a new position as a toxicological risk assessor. He also is a full-time parent to two adorable purple velvet plants: Planthony Bourdain and Marie Planthoinette.
Disclaimer
The viewpoints and information presented in Adverse Reactions represent those of the participating individuals. Although the Society of Toxicology holds the copyright to the production, it does not vet or review the information presented nor does presenting and distributing the Adverse Reactions podcast represent any proposal or endorsement of any position by the Society.
Adverse Reactions
The Life-Giving Properties of Liquid Gold
With limited existing research on the effects of medications and exposures on lactation, Christina D. Chambers, University of California San Diego, shares work underway to better assess risks and benefits for mom and baby. Co-hosts Anne Chappelle and David Faulkner also discuss with Dr. Chambers the tricky roles of epidemiology and observational studies.
About the Guest
Christina D. Chambers, PhD, MPH, is a Professor in the Department of Pediatrics and the Department of Family and Preventative Medicine at the University of California San Diego (UC San Diego) and Co-director of the Center for Better Beginnings. She also is a Clinical Professor in the Skaggs School of Pharmacy and Pharmaceutical Sciences at UC San Diego, Vice Chair of Clinical Research in the UC San Diego Department of Pediatrics, Director of the UC San Diego CTRI Center for Life Course Research, and Director of Clinical Research at Rady Children’s Hospital–San Diego.
Dr. Chambers is a perinatal epidemiologist specializing in environmental causes of adverse pregnancy outcomes, birth defects, and childhood disabilities, with a special focus on human teratogens (environmental agents that cause birth defects or other adverse prenatal outcomes). She is currently conducting research on the prevention of alcohol-related birth defects, the safety in pregnancy of several new medications used for the treatment of maternal health conditions, and the safety of vaccines during pregnancy. Dr. Chambers serves as an advisor to national and international organizations such as the National Institutes of Health, the US Food and Drug Administration, the Centers for Disease Control and Prevention, and the World Health Organization (WHO).
Send SOT thoughts on the episodes, ideas for future topics, and more.
[00:00:00] Adverse Reactions “Decompose” Theme Music
[00:00:05] David Faulkner: Hello, and welcome to Adverse Reactions Season 2. My name is David Faulkner, and this is my co-host,
[00:00:11] Anne Chappelle: Anne Chappelle.
[00:00:12] David Faulkner: As much fun as the first season of Adverse Reactions was, I think Season 2 is better.
[00:00:16] Anne Chappelle: Hidden.
[00:00:17] David Faulkner: Secretive.
[00:00:18] Anne Chappelle: Exactly.
[00:00:19] David Faulkner: The toxicology that happens when you’re not looking,
[00:00:22] Anne Chappelle: or toxicology that you forgot about.
[00:00:24] David Faulkner: It’s still important, and we’re here to talk about it. Welcome to Season 2 of Adverse Reactions:
[00:00:28] Anne Chappelle: “Hidden Toxicology.”
[00:00:31] Adverse Reactions “Decompose” Theme Music
[00:00:37] David Faulkner: A legacy of looking at the life-giving properties of lactose.
[00:00:42] Christina Chambers: When it comes to lactation, that’s been sort of the ignored sibling in this whole thing. There’ve been few required post-marketing commitments to do any lactation studies at all.
[00:00:54] David Faulkner: Or,
[00:00:55] Anne Chappelle: Banking on milk: liquid gold with Christina Chambers.
[00:00:59] Christina Chambers: From a public health standpoint, this is probably the biggest challenge, is the communication to the public of what a finding is either way.
[00:01:07] Adverse Reactions “Decompose” Theme Music
[00:01:09] Anne Chappelle: Good day, everyone. My name is Anne Chappelle, and I’m here with:
[00:01:14] David Faulkner: David Faulkner.
[00:01:15] Anne Chappelle: And we are joined today by Dr. Christina Chambers. She is a Professor of pediatrics at the University of California San Diego and Vice Chair of Clinical Research for the Department of Pediatrics at UCSD and Rady Children’s Hospital. She’s a perinatal epidemiologist. And I want to know more about what that is.
[00:01:37] Christina Chambers: The area that I work in is sort of the study of health and disease—person, place, and time—as it relates to the perinatal period. And the very special area that I do research in is what’s called teratology, so prenatal exposures that the mother might experience at any time during pregnancy—whether they’re environmental, medication, infections, underlying conditions—that interfere with the normal development of the baby. So, may increase the risk for birth defects, may increase the risk for growth deficiency, preterm delivery, neurodevelopmental problems. So, think isotretinoin or rubella, that may interfere with that normal development at biologically sensitive windows of time during pregnancy.
What I try to do is identify those exposures that may pose a risk so we can try to avoid them and those exposures that may not pose a risk so that we feel comfortable taking a medication or having a treatment during pregnancy. And then extending in the perinatal period to the postnatal period, I also work on research projects that look at the same issues as they relate to lactation. So, are there things that the mother may need to take while she’s breastfeeding that may get to the baby through the breast milk and may have some potential to interfere with growth or cause some sort of side effects in the infant? Or conversely and just as important, are there things that we should demonstrate that the lactating person can use safely and not be concerned about the baby?
[00:03:07] Anne Chappelle: So, as a definition, just so I’m clear, “perinatal” is just until birth?
[00:03:13] Christina Chambers: Nope, it covers that whole spectrum. So, actually, the work that we do extends long beyond that, but it goes back to that perinatal period—so, the period around pregnancy, so including the postnatal period, but the period around pregnancy. And then when we’re looking at child health outcomes, we would like to be able to look at those through the whole life span and even subsequent generations. A classic example is diethylstilbestrol. So, here’s a drug that was used quite commonly many years ago in pregnancy, and it turned out that the outcome, the adverse outcome, that was associated with it wasn’t really appreciated until many years later because it was certain types of cancer in the offspring many years later. So, the outcome may not be appreciated, whether it’s neurodevelopment or an increased risk for cancer, until many years after that prenatal exposure.
[00:04:01] David Faulkner: So, you’re looking forward and back from birth, basically?
[00:04:05] Christina Chambers: The work that I do is almost exclusively prospective cohort studies. So, we’re following women during pregnancy who have had an exposure. So, we’re looking back and saying, which exposures did you have and which are you going to have through the rest of pregnancy? Before she knows what the outcome of that pregnancy is. And then we follow her children longitudinally. In the breast milk studies, these are quasi-prospective. So, women enroll in breast milk studies who are using a medication or have an exposure or maybe don’t know they’ve had an exposure. And then we’re looking at assaying what’s in the milk and then also following those children for growth and development. So, is there any indication that that source of whatever’s in the milk has any impact on growth and development of the child?
[00:04:48] David Faulkner: And I’ve heard the phrase “breast is best.” Breast milk is talked about being liquid gold. What is it that makes breast milk so special?
[00:04:57] Christina Chambers: Well, that’s the $64,000 question, and what it points to is that we know very little. And here, it’s just an amazing thing in the scientific world that we have a tissue that is recommended to be the only source of nutrition, and certainly the primary source of nutrition, for every child in the universe, and yet we don’t know enough about the components of it, how it functions, and so on, and it’s been a neglected area of research. That’s changing. NIH and others are now putting more resources towards supporting research in this area so we can learn more about it. But we do know from the research that has been done that obviously the reason why breast milk is suggested as the primary source of nutrition is that there are many benefits associated with it, including passive immunity for things that the baby may not have its own immunity to already; well-balanced and actually source of nutrition that sort of accommodates the infant, so paired directly with the infant, and has some components in it, like, we know it has these human oligosaccharides in it which seem to provide protection against various things, including in premature infants necrotizing enterocolitis, which can be lethal condition in preemies; many other components in it that seem to provide benefit both in terms of reduced risk of subsequent obesity or diabetes. It’s still a little bit controversial, but there seems to be evidence that it may provide benefit in terms of cognitive performance. And it’s also the whole picture; it’s not just the milk itself but the fact of breastfeeding, so the bond that’s created between the mother and the baby.
So, “breast is best,” I think, is a term that’s thrown around not to—and I think this is important—not to disparage people who choose to or need to formula feed or for whatever reason cannot breastfeed. That’s not a bad thing. It’s just that if you have the opportunity, ability, and can do this, that there are many benefits that have been demonstrated for breast milk as the primary source of nutrition for infants at least through the first six months life.
[00:07:03] Anne Chappelle: I know for me, I did breastfeed both of my children, and as a scientist, it is fascinating that all of a sudden—first of all, pregnancy was just a wild ride anyway. But most men know what all of their body parts are for, and it isn’t until a woman lactates that you’re like, oh, that’s what they’re here to do. Your body does this incredible thing, and as a scientist and as someone who likes be in control all the time, I’m like, what is my body doing? Look at this! But it was really fascinating, just from a physiological.
[00:07:36] Christina Chambers: Absolutely, a hundred percent. And the fact that it’s this feedback loop, where you produce the amount that the baby wants, at the times that the baby wants, is just an amazing thing. And it’s really amazing it’s kind of tailored to the infant itself; there’s evidence, as I understand it, that the composition of milk that you produce is different for a male baby versus a female baby, that the protein-carbohydrate-fat proportions are different, and that’s actually set up long before delivery. This whole process is very finely tuned be able to support human life in those very vulnerable early weeks after delivery.
[00:08:12] Anne Chappelle: Why do you think it’s been neglected?
[00:08:15] Christina Chambers: I think for many years this was something that nobody ever did in public, so it was sort of a hidden thing, and maybe not thought to be something that was worthy of scientific endeavors. But the more people look at it, the more important it has become. Certainly, studies of exposures in pregnancy have not received the research resources they should have, and women have been excluded from clinical trials who are pregnant, and so on, but when it comes to lactation it’s always been kind of a different story.
So, in pregnancy you can say, well, the mom has hypertension or the mom has asthma and she needs to be treated, so we’re going to give this medication. In lactation, there’s always been this out that you can say, well, you can just stop breastfeeding, and you have an alternative source of nutrition, or you can just not take the medication—neither of which is the optimum choice. The optimum choice is to say we know that this is OK to use while breastfeeding, or we don’t know, and to make the choice based on data rather than having this alternative being that you would not breastfeed if you needed to take a medication that you weren’t sure of its safety. And that’s, for the reasons we said, then maybe you’re not providing your child with what would be the benefits of breast milk for a reason that could be addressed.
I think the interest now is both on the pregnancy side and the lactation side. In last few years we’ve had this PRGLAC task force that was established by the 21st Century Cures Act. So, the Department of Health and Human Services had to establish a task force to address gaps in needs for maternal and pediatric therapeutics. And that has really brought this to the fore, that there’s not enough resources being put towards this, not good training programs that prepare people to able to do the toxicology and pharmacology that’s related to this, and that there needs be a more aggressive effort to try to develop this information both in pregnancy and lactation.
[00:10:02] David Faulkner: So, this is really important. How do you do this research? You can’t experiment on people, and you would never want to do that with this population. So, what do you do to get at these questions?
[00:10:12] Christina Chambers: In the pregnancy arena, there has been reluctance to include pregnant women in clinical trials, in randomized clinical trials, which would be the gold standard. So, the majority of research that has been done has been observational. So, rather than randomizing women to receiving this or not, you observe people who are already being prescribed this or have taken this medication and compare them to women who haven’t. There’s movement in the direction. There’s draft guidance out by the FDA now to actually outline circumstances under which women should be and could be included in randomized clinical trials.
And this came up recently with the COVID vaccines. In the haste of getting these out there, pregnant women were initially excluded from the clinical trials but could have been included. In the breastfeeding arena, same thing: there’s a reluctance to randomize people to saying, here, take this and let’s see what gets into your breast milk and gets to your baby. Although there are circumstances where people are getting ready to quit breastfeeding—they’re weaning—and would be willing to start a drug and collect milk samples and be able to do that prior to stopping lactation. But mostly, it’s observational studies, so people who are taking the medication or not and you’re looking at the observational follow-up of those children. Those are the traditional ways it’s done. There are things in the works—trying to do mammary-gland-in-a-dish or placenta-in-a-dish or whatever so that we can do a better job of screening things without having to do it in vivo.
[00:11:35] David Faulkner: It’s striking to me that guidance is on the way. What year is it? We’re just figuring this out?
[00:11:42] Christina Chambers: I totally hear you. There’s very outspoken camps on this issue about why have woman been excluded from these types of research studies on the pregnancy end of it, and honestly, you understand why. If you were pregnant woman, would you want to say, “Oh, OK, I’ll get randomized to receiving a drug that nobody’s tested in pregnant women to see if it affects my baby.” Who would want to do that? What does happen is women get pregnant or people get pregnant in clinical trials inadvertently. It happens all the time, sometimes more than others, and so we capture some information from that, but it’s really never enough. It’s never enough exposed pregnancies. So, the observational route has been the way to go. We have some good sources of observational data. We have the Scandinavian countries who basically collect all of the exposure information, all the outcome information, for 90% of the population and are able to look at those things.
When it comes to lactation, that’s been sort of the ignored sibling in this whole thing. There’ve been few required post-marketing commitments to do any lactation studies at all. It’s now becoming much more common that they’re paired with a pregnancy study when a new drug is approved to say, you have to do this. There is a lactation guidance for how you do the studies. To my way of thinking, the first question you want to answer is, Does this agent get in the milk, and at what level? And if it’s not there, then you don’t need to do any more. And if it does and there’s reason to pursue that, then you want to look at how much the baby’s ingesting and is there any concern for that having not just innocuous effects? The research is completely possible to do and it’s really only recently that it’s become much more on the top of the radar.
[00:13:19] Anne Chappelle: I was going to ask: the EU is mandating a lot of testing right now for a program called REACH for registration of chemicals, and they’re taking a pretty hard look at repro and developmental potential toxicants. Is there a really good animal model for some of this?
[00:13:38] Christina Chambers: I am not the expert in this, but in talking with Phil Anderson, who is the expert, my understanding is that the model that’s typically used, which is rat milk, is really not a good model to translate directly to humans. That it needs to be done in humans, certainly. Whether it’s animal studies or screening of toxicants through some other model, there are huge benefits and ways that we can improve on our predictive modeling for which ones of these things should we be more concerned about? I think that’s terrific. But in the end that proof of whether something does have the potential to be harmful or not in humans has to be demonstrated in humans.
But thinking or building into the whole process every step of the way what is it we learn about this in the preclinical setting that will get us closer to a better understanding of how it might function in humans? And if and when can we safely move forward with doing this kind of testing in humans? Instead of waiting like we do now. We wait 10 years hoping somebody would have initiated a study.
EU funded, starting I think about three years ago, something called the Conception Project. It is a very well-resourced set of projects across multiple countries in the EU that’s bringing together every aspect of this, from what are the preclinical signals, what databases can we mine to look for things where we should be concerned about it and we just haven’t taken a look yet? They used our breast milk biorepository protocol to establish an EU-wide breast milk bank. They’ve set up a protocol to collect samples and to actually pair it with a blood sample from the mom so that they can start to address issues about exposures during lactation. And I think that’s really going to be, just like ours, I think it’s a really hugely valuable resource, not only to be able to address this issue about medications and vaccines, but as a broad representation about what environmental chemicals and other things, what is the prevalence of their occurrence in milk samples from people, and are these potentially of any concern to the baby? But also, it gives us an idea about how prevalent they are in the environment.
[00:15:42] Anne Chappelle: It’s easy to see a birth defect such as a cleft lip. It’s difficult when we talked about DES and the increase in vaginal cancer in the female offspring. When you start talking about neurodevelopmental effects, we’ve seen a huge increase in the last 20, 30 years on diagnosis of autism spectrum disorders. There’s a lot of questions about how those came to be. Is it that we are looking for them more and diagnosing them more? So, how do you feel about some of these other endpoints, these more subtle endpoints, for neurodevelopmental effects? Do you think that there is potentially a link between these kinds of disorders and maternal exposures?
[00:16:24] Christina Chambers: I absolutely do. And I think when you think of the spectrum of adverse outcomes in teratology, it’s death at one end, so spontaneous abortion or stillbirth, but at the other end, it’s functional deficits. That’s part of the whole spectrum. And so, we have many examples of human teratogens that may increase the risk for birth defects but also increase the risk for neurodevelopmental or other functional abnormalities. So, it’s an absolutely reasonable endpoint to study, but one of the more difficult ones. The longer you go postnatally, the more other factors that you aren’t measuring may be playing a role. And then you have all of the issues about who goes in to get diagnosed and what are those factors?
I don’t know if you’ve been following the literature now, but there’s a big controversy over acetaminophen. So, the most commonly used over-the-counter medication in pregnancy and probably anywhere, more than 60% of pregnant women use it at some time in pregnancy, but there’s been five or six studies that have suggested that at least with repeated use across pregnancy there’s an increased risk for autism spectrum disorders, for some cognitive deficits, for attention deficit hyperactivity disorder. So, all of those things, yes, those are endpoints that are absolutely a hundred percent important to look at, but I think what we’re struggling with is finding the best methods for doing that so that we don’t find these spurious associations that make people worried about something that maybe they don’t need to be. It is difficult.
I mentioned Conception Project in Europe. One of the pieces of that is to try to develop the best methods and model for looking at long-term outcomes. So, what do you begin with? What’s the testing battery you begin with, and do you tailor it to what you know about the toxicology or pharmacology of that drug or that exposure? Some people think, well, you start with anything that affects the CNS in the adult who’s exposed to it and that’s your high priority to go forward, but it’s a lesson learned. The European Medicines Agency was really concerned about valproic acid. So, here’s a drug that’s been around for many years. We know now that it’s associated not only with increased risk for birth defects but also for some learning deficits, and that it’s very clear that’s the case. But why didn’t we know that? Why are we learning this 20 years from now? Well, because we didn’t have a system in place to be able look at that.
But again, you have that big, intervening period between zero and whatever it is, you know, five or six years of age, where to get sufficient numbers to look at these differences in exposed or not exposed, maybe you’re going to a health system where everybody gets tested at school age or something like that. And if you’re dealing with a smaller sample of kids that you follow very carefully, then you’ve got to have a pretty big hit in order to be able to detect it. So, it is a challenge and a hundred percent worthwhile. I mean, when you think of things that impact the whole population and it’s something that’s avoidable, a hundred percent.
But think of all the factors that have been implicated. You’re looking at these ecological studies where we say, OK, air pollution has increased and now we have more autism. So, you have all these ecological data that says, well, we think there may be a risk. You still have to do the individual-level study that’s really done. It’s really a challenge to do them.
[00:19:35] David Faulkner: As an epidemiologist, are there times when a report come out where it’s, “Oh, this is linked to this”? Basically, have you seen your discipline used for evil?
[00:19:44] Christina Chambers: Oh, for sure, from a practical standpoint. Historically, the example is Bendectin. This is the drug that was widely used for nausea and vomiting of pregnancy, and three to five percent of babies are going to be born with a birth defect and a third of women at least were using Bendectin for nausea and vomiting and pregnancy, and so some of those moms had babies with birth defects. This led to a number of lawsuits, and ultimately, the drug was withdrawn from the market, not because there was any good scientific evidence that the drug caused birth defects, but because of the litigation. And so, the company withdrew it. And so, it wasn’t until many years later it’s finally remarketed by a new company in the US but fighting a big cloud that carried over from something where the scientific evidence was just not there to support that it caused birth defects.
[00:20:31] David Faulkner: That gets into a really interesting ethical question about the type of work that you do. How do you decide the types of questions you want to ask, with the understanding that if anything happens during or after pregnancy, someone is going to be looking for an answer? They’re going to be looking for a reason. And it seems like with research that you do, you have to be very careful.
[00:20:55] Christina Chambers: From a public health standpoint, this is probably the biggest challenge, is the communication to the public of what a finding is either way. Sometimes, you’re saying, we don’t see any increased risk here, our confidence intervals are wide, and the public has no idea what that means. So, that’s a hard communication. Or sometimes, you say, this study shows an increased risk of 1.5 for a defect that occurs in one in 50,000 pregnancies. So, your risk if you take this drug is minuscule in scheme of things, but how do you communicate that in a way that the patient and their provider feels comfortable with saying, gee, the benefits to me of taking this drug outweigh this minuscule possible increased risk that I might have? Some people don’t accept that; some people do. You always come out there tentatively saying, this needs to be replicated in other studies, these are our findings, and not wanting to be too aggressive, but not wanting to ignore or sweep under the rug, so to speak, something that may be a finding.
I think the big issue is getting the replication studies done in a timely fashion. We’ve just done horribly with that. What we’ve done is said, oh, OK, we see a signal in a pregnancy registry, so then we’ll do a cohort study, and 10 years later we’ll have the answer to that. That’s not the way it should be. The way it should be—and we and others are working towards this—is to have simultaneously, in parallel, sources of information that you can tap into. So, can you say, OK, we see something here. We see increased risk of conotruncal heart defects with this drug exposure in early gestation. Let’s go over to a claims data source and see if we can pull out that same exposure there, and do we see the same finding? But being able to do it really pretty much in lock step so that we don’t raise the specter of this may be a problem, but gee, we’ll tell you for sure 10 years from now.
[00:22:40] David Faulkner: You’ve mentioned Europe a couple of times. The Scandinavian countries, well known for excellent record keeping. I remember learning in my epigenetics class and how the Dutch winter famine, just this great study. So, in terms of what the US is doing now in the organizations you’re working with, what do you see for the future of this type of research?
[00:23:00] Christina Chambers: We hosted a workshop on this very topic—2018 at FDA. The purpose of it was to bring together everybody who does work in this field with different perspective. So, Europeans, the people who do case control studies, the CDC, people who do disease-based registries, like there’s a whole antiretroviral drugs and pregnancy registry that covers the whole HIV community worldwide, pharmacology people who do N-of-1–type studies, and so on. Pulling that all together to say, how could we work together so that we have an orchestrated approach? And I think this Conception Project I mentioned, in Europe, that’s what they’re trying to do. They’re trying to pull together multiple types of data and then have a knowledge that the public and providers can go to to say, OK, this is the most recent thing that we know. That, I think, needs to be global and there’s no reason it can’t be.
But I wanted to go back to the question you asked before. I think that the human animal is where you finally have to answer the question about humans. But in case after case, especially with birth defects, you can go back and then find what is the animal model where you can do this. We’ve done that with other drugs, where you can better understand the mechanism of action, you can better understand that particular gestational timing that’s important, and so on, by going back to the animal model or whatever system that you have to better understand what you’re seeing observationally in humans. And I think there will always continue to be a role for that.
[00:24:24] Anne Chappelle: We’ve talked in some other podcasts about big data. And usually when I think of big data, I think of these big databases when it comes to air monitoring, but there’s these FAIR data practices to make it find-able, accessible, and shareable. How do you make the data anonymous enough but collect enough, tag it enough, that you can mine this data? And using these artificial intelligent mining procedures to help do some of that heavy lifting, but you have to have it in the right format first.
[00:24:54] Christina Chambers: I agree. And there’s been a lot of work on the claims data front to doing that. In the US, millions of births every year covered by whether it’s public or private insurance where claims data is available, it’s de-identified, available for researchers to use, there’s no selection bias because you don’t have consent to be part of it collected for another purpose, so it’s very efficient economically to approach. And a lot of work has been done to develop methods for addressing the limitations of that data. You may not know exactly the date the person got pregnant. How do you define that a miscarriage took place because it may not have taken place in the hospital? How do you define gestational age as far as preterm birth? So, a whole lot of algorithm-type work. When you look at a birth defect in claims data source, how often is it concordant or discordant with what the medical record actually says? So, they’ve done some validation work there and really gone a long way towards making these databases useful. And they’re really a huge resource, I mentioned earlier, for signal detection. So, to go in every year and monitor and say, OK, what do we see for this, this, and this? Way better, in my opinion, than the things that we’ve had in the past, like the Adverse Event Reporting System that the FDA has, where really not very much has been identified through that at all.
I think the limitations of claims data are you don’t typically know whether the mother took the drug or not. You don’t know if she’s taken a drug that somebody else gave her because there’s lots of shared medication out there that wouldn’t show up there. It was a big problem with vaccines. You knew in claims data who got vaccinated, but you didn’t know who got vaccinated someplace else. And you don’t know smoking, you don’t know about folic acid use, important confounders. You don’t know about alcohol use, typically. Those are things that are limitations. That being said, everything has its limitations. The FDA has set up the Sentinel system, which is electronic health records across multiple systems. So, a little more detailed information where they can periodically query this for, using AI, to see are there signals of adverse events showing up? And within that they have what’s called Mini Sentinel, where they’re actually looking at pregnancy. Can you use this as an automated detection system to say, oh, this should rise to the forefront and we should look at this a little more closely?
So, you mentioned the Scandinavian countries. I count those as big data. We have a neat project I just love in the state of California, and California it’s such a big state, so if you have half a million births a year, we can go back over just the last couple of decades and get all of the deliveries in the state of California hospital discharge data. And then what we’re working on is linking that to Medi-Cal claims, which is our public insurance but really covers a huge proportion of pregnancies, because you automatically qualify if you’re pregnant, to be able to look at large data at specific questions related to exposures in pregnancy and maybe at some point in lactation as well. There’s huge advantages to big data, to mining it, but that doesn’t take away the need and requirement for good scientific judgment to be able to be sure that is a cause and effect.
[00:27:55] Anne Chappelle: Well, I know in some of the things that I follow, they’ll say, well, we’ve got 10 cases this year. And you’re like, yeah, but you’re not looking at all the number of people who are exposed. And trying to get to who is exposed and how. So, we have to be very clear about the usefulness of surveillance programs versus Sentinel-type programs.
[00:28:13] Christina Chambers: I agree. And I mentioned FDA’s Adverse Event Reporting System. That’s always been the problem, is you don’t have a denominator of everybody exposed; you only have those who have the adverse outcome. And until you can put that in context, it’s not a very useful method for identifying things that might be a problem.
[00:28:28] David Faulkner: Well, as we’re winding down, we have a couple questions that we try to ask. What was most significant adverse reaction that you’ve ever experienced?
[00:28:36] Christina Chambers: Well, I’ll say something that’s related to the area that I work in. So, the first paper that I published happened to get a lot of press, and I was just completing my master’s degree and was pretty naïve. And because it was raising concerns about a medication that a lot of people use in pregnancy, and the adverse reaction I felt was how you deal with the press. The press will come after a topic like that and really challenge you as a human being, as a scientist, or how dare you say these things? If it’s a controversial topic, I think it’s part and parcel of the field we work in that you have deal with it, but sometimes many of us are not prepared for how strong an impact that can be. Now, I know people go through as of their graduate training programs how to deal with communication with the press and the public, how to deal with spin, and all that sort of stuff, so hopefully are better prepared for it, but that was a wakeup call for me.
[00:29:37] David Faulkner: Another question that we like to ask is, what would you be doing if you weren’t doing what you’re doing now?
[00:29:42] Christina Chambers: Oh, I can’t imagine I would be doing. And I hope I get to it for another 10 or 15 years. So, I’ve been hugely fortunate—and I tell my kids this—you always tell your kids, oh, follow your dream, do the thing that’s really is meaningful to you. So often that’s not easy to do. You have to do what you have to do. And I’ve been extremely fortunate to be able to do something I absolutely, absolutely love and lucky to be able to carry this out and talk to you guys.
[00:30:10] Anne Chappelle: And on that note.
[00:30:13] David Faulkner: Well, thank you so much for speaking with us today. This has been a lot of fun. I still have a lot of questions but only have so much time. But thank you.
[00:30:20] Christina Chambers: It’s nice to hear your enthusiasm.
[00:30:23] Adverse Reactions “Decompose” Theme Music
[00:30:29] Anne Chappelle: On the next episode of Adverse Reactions:
[00:30:33] David Faulkner: Biostatistics, the hottest science. Or, heat stressed: Howard Chang talks biostats and public health.
[00:30:40] Howard Chang: I think there are situations where your data just don’t support your hypothesis or there’s something wrong with data collection. And I think we just have to move on.
[00:30:49] Adverse Reactions “Decompose” Theme Music
[00:30:53] Anne Chappelle: Thank you, all, for joining us for this episode of Adverse Reactions, presented by the Society of Toxicology.
[00:30:59] David Faulkner: And thank you to Dave Leve at Ma3stro Studios.
[00:31:02] Anne Chappelle: That’s Ma3stro with a three, not an E.
[00:31:05] David Faulkner: Who created and produced all the music for Adverse Reactions, including the theme song, “Decompose.”
[00:31:11] Anne Chappelle: The viewpoints and information presented in Adverse Reactions represent those of the participating individuals. Although the Society of Toxicology holds the copyright to this production, it has,
[00:31:23] David Faulkner: definitely,
[00:31:24] Anne Chappelle: not vetted or reviewed the information presented herein,
[00:31:28] David Faulkner: nor does presenting and distributing this podcast represent any proposal or endorsement of any position by the Society.
[00:31:34] Anne Chappelle: You can find out more information about the show at AdverseReactionsPodcast.com,
[00:31:40] David Faulkner: and more information about the Society of Toxicology on Facebook, Instagram, LinkedIn, and Twitter.
[00:31:46] Anne Chappelle: I’m Anne Chappelle.
[00:31:47] David Faulkner: And I’m David Faulkner.
[00:31:49] Anne Chappelle: This podcast was approved by Anne’s mom.
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[00:31:57] End of Transcript