Lea Ann Chen, MD Explains Manifestations of IBD Based on Race and Immigration Status

In this podcast, Dr Lea Ann Chen explains how race/ ethnicity (White, Black, Hispanic, Asian) and immigration status (US-born vs foreign-born) influence IBD manifestations, disease onset, treatments, and outcomes.

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Lea Ann Chen, MD, is an assistant professor of medicine in the division of gastroenterology and hepatology, and also the director of inflammatory bowel disease translational research at the Rutgers Robert Wood Johnson School of Medicine.

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Transcript:

Priyam Vora:

Welcome to this podcast from the Gastroenterology Learning Network. I'm your host, Priyam Vora, and today we are talking with Dr Lea Ann Chen. Dr Chen is an assistant professor of medicine in the division of gastroenterology and hepatology, and the director of Inflammatory Bowel Disease Translational Research at the Rutgers Robert Wood Johnson School of Medicine. Today we are going to discuss her research on how race or ethnicity and immigration status may influence IBD manifestations treatments and outcomes. Thank you for joining us today, Dr Chen.

Dr Lea Ann Chen:

Thanks so much for having me.

Priyam Vora:

Okay. So first question, what prompted your research into studying the manifestations of IBD from this angle?

Dr Chen:

So we've been really interested in the changing epidemiology of inflammatory bowel disease. So it's a disease that has mainly been or traditionally been seen in North America or western Europe. And over the past several decades, there's been this great increase in incidents and prevalence of IBD in other parts of the world. In addition to Caucasians, we're seeing it a lot more in Asians, Hispanics, Blacks, etc.

There have been studies to look at outcomes of patients with inflammatory bowel disease, but these studies oftentimes are confounded by socioeconomic differences between racial groups. So we had the opportunity to look and, and study the IBD patients at a safety net public hospital in New York City. It was a very diverse patient population. There were a number of new Americans and recent immigrants in this patient population as well. We really wanted to capture the diversity of IBD that we're seeing globally. But it also provided us a chance to account for socioeconomic status because it's a safety net hospital. More of the patients were of similar socioeconomic status intended to be either uninsured or underinsured.

Priyam Vora:

So would you describe your study?

Dr Chen:

Sure. We looked at almost 600 patients in this hospital. We found that it was probably a more diverse patient population, particularly as it relates to a standard IBD clinic. So only about a third of the patients were Caucasian, about a quarter of them were Hispanic, about a quarter of them were Black and then the rest were Asian. We did have a very small multiracial or other group.

We found that there were differences in the way that IBD presented based off of these racial groups. And so what we did was we used the Caucasian population as a reference and we kind of compared the IBD characteristics between a certain race and what the presentation was like in the Caucasians. For example, we found that in the Asian population that there was a very strong predominance of male patients compared to female patients and Asians that was not seen in the White population.

We also noticed, for example, that Black patients tended to have more Crohn's disease compared to White patients in this same safety net hospital. So we were able to learn a little bit more about disease characteristics and behavior that we think are more specific to race and environment and less confounded by socioeconomic status.

Priyam Vora:

About the results of your study, what did you find?

Dr Chen:

In addition to the differences that we were seeing by race, we also saw that there were quite a few differences between patients who were born outside of the US compared to those in the US and that was regardless of race actually for patients who were born outside of the US. I'll say a caveat here is that these patients probably did come from low incidence IBD countries as opposed to, you know, immigrants from, you know, Europe and Canada and, and other places where IBD incidences is high.

But these foreign-born patients were more likely to have ulcerative colitis. They were more likely to be diagnosed in adulthood as opposed to as children. They overall showed a less aggressive phenotype to their IBD.

Priyam Vora:

So going into specifics—I know you touched upon a lot of these points—but what did you find out about the characteristics of IBD by race among the four groups?

Dr Chen:

Yeah, so you know, for example, we showed that in the Black patients, they tend to have a more aggressive phenotype. For example, they were more likely to require surgery for their disease. That could also partly be because they were more likely to have Crohn's disease, which may require more surgeries in one's lifetime.

But what was really interesting is when we looked at foreign-born Black patients, mainly patients from Africa and the Caribbean, we didn't see this, we saw that, again, they were more ulcerative colitis, they had less aggressive disease. So even within a single race, you could see how environmental changes like where you were born may potentially impact disease.

Priyam Vora:

I know you said about the patients from foreign born status, they had disease late onset. So was it, what could be the reasons? Could it be because the manifestations were later or could it be because the access of care was delayed for them? Or maybe the country of origin could have played a role in the onset of disease?

Dr Chen:

Yes. So, one of the reasons why we wanted to focus in this particular patient population is because they all had similar access to care the way that the safety net hospital provides care that's less of an issue for patients. So, we can kind of remove that confounding influence. I think what has been one of the things that we find particularly interesting is that in inflammatory bowel disease, disease activity and disease severity can change over time within a patient, but it also changes over time in countries. So, what studies have been showing is that when IBD “enters a country”, it tends to be ulcerative colitis first. Then over the next couple of decades there's more Crohn's disease. So in a place like us, it's closer to, you know, half and half.

But in places where IBD is starting to develop, there's definitely a UC predominance. Our foreign-born patients tended to have more UC. Similarly in kind of these traditional high incidence countries, we're seeing more people diagnosed earlier. Also, more kids for example, are being diagnosed with inflammatory bowel disease. This is less so in a country where IBD is starting to develop.

We see that same parallel when we study our foreign-born patients. I think that that tells us something about the disease pathophysiology. Even though we know there are genetic variations that predispose to IBD, I think this change that we see in immigrants, the changes that we see in epidemiology tells us that there's a very strong environmental component to IBD risk. I don't think we know exactly what some of those environmental changes are. I think that's certainly a topic of very high interest—diet, antibiotic use, other things in the environment likely play a role, but it's definitely something more than just our genetics.

Priyam Vora:

Do the results offer more insight on the disease manifestations based on like completely different factors such as gender or diet or lifestyle habits?

Dr Chen:

Yeah, so even though we were very interested in the potential role of environment, there were some things that we saw that were consistent across the US born and foreign-born patients. For example, the predominance of the male gender being affected in Asians. We saw in both US born and foreign-born subjects. And I will say that our patient population tended to be consist more of East Asians. This finding may not be true of all Asian populations, but it was something that was consistent. We think that potentially that might be a finding that has more of a genetic basis, whereas some of the changes that we see between the foreign-born and the US-born patient populations we suspect may be attributed to environmental differences.

Priyam Vora:

What are the key takeaway points of this research?

Dr Chen:

So I think one of the key things that our research helps to show is that there truly are differences in disease behavior and manifestations that are associated with race that aren't related to access to care and to economic status. And I think it helps clinicians in that we don't have great predictors of disease prognosis, but this is something that may potentially help providers in terms of personalizing therapy to their particular patient. It's always a balance choosing a therapy that's sufficiently effective and potent, but also may carry the risk of adverse effects. If your patient is from a place where they may more likely have a milder form of disease, then that's something you can take into consideration when choosing a therapy for that person.

Priyam Vora:

So based on that, what are your recommendations to general practitioners or gastroenterologist specifically?

Dr Chen:

I think that the takeaway is that you can try to use a personalized approach. Certainly this type of study needs to be reproduced. It gives us kind of a broader sense of the causes and the things that influence IBD but isn't necessarily tailored to helping with every patient in terms of clinical care. But I think it teaches us a lot about the diseases and, and how we should be thinking about it broadly and kind of what the next steps might be in terms of the research.

Priyam Vora:

And do you have any plans to expand this to a broader study?

Dr Chen:

Yeah, so, you know, this is a primarily descriptive study. We're describing the differences in patients, but we're not able to fully explain why these differences exist. And so the work in my lab has been focused on understanding the genetic and microbial contributors to inflammatory bowel disease. We want to leverage our clinical insights from studies like this to help us find particular targets that we may, one day be able to actually leverage or utilize in patient care.

Priyam Vora:

Thank you so much for taking the time to talk to us Dr. Chen. Once again, for our listeners, that was Dr. Lea Ann Chen explaining how IBD phenotype made vary vastly by race and also foreign bond status. The findings of a study could provide insight into intrinsic and environmental influences on IBD pathogenesis. Thank you, Dr. Chen.

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