MCS & Toxicant-Induced Loss of Tolerance (TILT): Shahir Masri

Aaron   00:05

Welcome to the Chemical Sensitivity Podcast. It's a podcast that amplifies the voices of people with MCS and highlights emerging research about the illness.

Aaron   00:15

In this episode, I'm speaking with Dr. Shahir Masri. 

Dr. Masri is a member of the Hoffman TILT program at the University of Texas Health Science Center in San Antonio. It's an organization that conducts critical research, education and outreach about Multiple Chemical Sensitivity and Toxic Induced Loss of Tolerance or TILT. Dr. Masri is also an assistant specialist in air pollution exposure assessment and epidemiology at the University of California Irvine. 

He teaches courses on environmental health and pollution at Chapman University in Orange, California, and National University in San Diego, California. Dr. Masri holds a doctorate in science from the Department of Environmental Health at the Harvard School of Public Health. 

In our conversation, we talked about how environmental scientists understand Multiple Chemical Sensitivity, why so many people with MCS struggle to get a medical diagnosis, and how the illness is likely to continue to affect millions of people in the coming years. 

I'm really grateful to Dr. Masri for taking time to speak on the podcast and for sharing his wealth of knowledge about MCS. I hope you find the insights he shares helpful and interesting. 

There's some minor audio issues at certain points throughout the interview – nothing serious, but I just wanted to draw your attention to that. And I hope you enjoy the interview.

Aaron   01:37

Well, Professor Masri, it's really great to meet with you today. I'm really looking forward to this conversation. I think listeners will really benefit from hearing you because of your expertise. And so thanks so much for taking time to do this. 

Shahir Masri  01:54

Absolutely. My pleasure. 

Aaron   01:56

So maybe before we jump into the conversation, I'd really like to ask you what brings you to this research around environmental health and Chemical Sensitivity and TILT? 

Shahir Masri  02:11

So my background is in environmental exposure assessment. So in my field, we're concerned with all kinds of exposures, ranging from foodborne contaminants, pesticides, lead in food, to air pollution, water contamination, etc. 

When you're studying these conventional pollutants, like air pollutants and all the rest, there's a wide body of literature that's focused on the things that come out of cars, emissions from consumer products, everything from carpet, indoor air pollution is a big research area, as well. These are the sort of main things that are studied. 

And they’re oftentimes easier to study in the sense that exposures are widely documented, readily measured, and health outcomes can be fairly consistent across different groups and different individuals. 

Shahir Masri  03:09

In the case of air pollution, we tend to see widespread associations with asthma, with chronic pulmonary obstructive disorder, emphysema. There's a whole host of consistent health outcomes. When we talk about lead exposure, there is a really strong relationship between lead exposure and neurodevelopmental outcomes and children decrement in IQ, things like that. 

So there's a consistent outcome that we can readily observe with a lot of the more conventional exposures that we think of. There's a real need to address a population that has described symptoms that are very similar to what we would see in people who have allergies that aren't really well studied, well defined. 

Shahir Masri  03:59

And I gravitated to that area, in part. It's not the only area that I study. But because there is this extensive need to address and better understand this problem, again, more often times with lower level exposures, not as high concentration in the environment, and oftentimes perplexing mix of outcomes and symptoms not always consistent from one case to the other. 

So there's a real need to understand this. 

Back towards the end of my graduate school studies, I linked up with a professor, Dr. Claudia Miller, who does work in Texas at San Antonio. She's a physician by training but also has an industrial hygiene background and she's worked at the university there for, gosh, over three decades, and ever since grad school we've been working on this area of Toxicant Induced Loss of Tolerance, and recently published a paper together that's looked at patterns of TILT among eight different exposed groups. 

So that's kind of a rough background of my area and how I ultimately gravitated in part to research Chemical Intolerance. 

Aaron   05:20

That's wonderful, and I think a lot of listeners will be familiar with Professor Miller's work and have read some of her work, and it's wonderful to hear that you're working together and collaborating. 

And so perhaps we could dive into this question – really, the question which is central to this discussion is, how do you as a researcher, a scientist understand Multiple Chemical Sensitivity? Maybe we could frame it in a way in layperson's terms, because I think a lot of us with MCS struggle to let others know what's happening. 

How do you understand that, and what happens in the body in the brain? 

Shahir Masri  06:01

Right. So there's a lot to be uncovered still about exactly what's happening physiologically, but somebody who's observing a person with MCS or TILT – and you'll find there's a variety of different sort of synonyms like environmental illness, it's been called Idiopathic Environmental Illness. We've been kind of shifting towards the use of the word TILT. So I just want to say that MCS and TILT for these purposes, we may use them interchangeably here, and I can get into the differences between those two, if you'd like. 

Shahir Masri  06:34

But what MCS looks like, what Chemical Intolerance looks like to somebody observing this in a person is very similar to what one might observe as, I use the word allergy. It's not a technically correct description of what's going on in a person who's affected by Chemical Intolerance, but from a person observing what's going on and hearing the sort of symptoms and description of the health problem, it sounds a lot like allergies.

Shahir Masri  07:02

The difference here is that if you go get an allergy test, and you're having a physiological allergic response, what they're going to be testing for is a spike in what's called IGE in your blood. So if you show this spike in IGE levels in your blood, that's an indication that, in fact, you are undergoing some allergic response to some so-called allergen. 

Now, in the case of Chemical Intolerance, we don't see these spikes in blood IGE levels. 

And for that reason, people who are suffering from Chemical Intolerance essentially are sort of left in the dark. They're defined as ‘not allergic’, they're not suffering from allergies. The doctor can't really help you, and on you go. Out the door. Maybe another doctor can help, but allergists, that's not their specialty. 

Shahir Masri  07:51

So that's the case for people suffering from Chemical Intolerance. Now, it doesn't mean that nothing is actually going on. It just means that what we know about these responses isn't consistent with what we know about allergic responses. So that’s the sort of distinction. 

Aaron   08:09

And I was going to save this question for later in our chat. But part of your work, I understand, is creating a set of diagnostic tools with Professor Miller and your colleagues. Do you think now would be a good time to just talk briefly about what those are? Because you pointed to the challenges that the traditional allergy tests don't pick up on MCS. They're not effective. 

Can you tell us a little bit about the diagnostic tools that you've developed? 

Shahir Masri  08:38

Yeah, so Dr. Miller and her team developed this before I came to work with them, but it's a really important tool. So as I mentioned, we don't have a convenient laboratory test that can show that a person is suffering from Chemical Intolerance, that can show this sort of biomarker or physiological response. 

So what Dr. Miller and her team created what is called a Quick Environmental Exposure and Sensitivity Inventory (QEESI), which is essentially a diagnostic tool. It's a survey that one can take to score their impacts, their reactions, health reactions to different range of different chemicals and allow for a quantification, a way to characterize and quantify and even rank the extent to which they either are or aren't impacted by environmental chemicals, and would be defined as somebody who's actually Chemically Intolerant. 

Shahir Masri  09:44

So this is a diagnostic tool that we encourage people to take to their physicians, to better understand their own symptoms, and also to allow their physicians to understand what's going on. So this is a tool that's now been used in over a dozen countries worldwide. A number of studies have been published that have used this diagnostic tool. 

And it's one of the most important things you can do if you're somebody who is suffering from Chemical Intolerance, is to go on to the tiltresearch.org website. Go ahead and take the QEESI, as it's called for short, and take that to your doctor. It's good for your own understanding. But it's also extremely important to take to your physician.

Aaron   10:33

That's fantastic. And there is a lot of denialism among the Western-trained medical community. And that's something I wanted to talk with you about. 

But given that level of skepticism, or denialism, people could say, ‘well, you're just making it up’, right? If you can't measure the level of reaction, like with an allergy test, for example, if you go to an HR department who one could go to to request accommodation at work, they could say ‘well, it's not a trustworthy test.’ 

Is this a real diagnostic tool that can really work? And how well known is it among the medical community, like if I were to take it to my doctor? 

Shahir Masri  11:20

It's not extremely well known, just as the whole field of Chemical Intolerance is not extremely well known within the medical field. In fact, if you open up the environmental health textbook that I used to teach in my classes, you'll see that Multiple Chemical Sensitivity, as it's referred to in the book, amounts to about a paragraph at the end of one chapter. And this is a several hundred page environmental health textbook. 

So there's an acknowledgement within environmental health that this is a phenomenon that exists, but again, there's not a whole lot of physiological literature, toxicological literature that has uncovered the mechanisms behind this. It's not very easy to study, for reasons like I've mentioned briefly, and I can get into it, but that doesn't mean it doesn't exist. 

Shahir Masri  12:21

And talking about your question, we point people back to the germ theory. Previous to being able to, through microscopes, see this sort of invisible world that's invisible to the naked eye, and previous to research that over and over again began to show that there are, in fact, these microscopic organisms that lead to pathogenic, communicable diseases, it was also enigmatic. It was a mystery as to why people were getting sick with a variety of diseases that were related to water contamination, germs, and viruses and bacteria. 

Shahir Masri  13:06

So we can't confuse our infancy in our understanding of a certain disease system with a rejection of the potential that there is some sort of explanation as to what's going on. Just because we haven't discovered all the details surrounding something, it's, I think, myopic to say that this is just mental. 

Shahir Masri  13:31

And I actually think it's also important to point out that we try to draw a distinct line between what’s sort of psychological and physiological, but there's not really a sharp line to be drawn. We are a biochemical system, our entire body – from the kinds of neurotransmission, and thoughts, and neurological system in our body to every other aspect of our body. 

Shahir Masri  14:01

We are a biochemical system that influences. Chemicals influence our mood. Trace amounts of hormones dramatically influence the way we feel both mentally, physically. So to draw a real hard line between what's going on mentally and emotionally to other chemical aspects of our bodies, I think is to kind of forget the fact that we are a chemical reaction. 

Our entire body is a chemical reaction, from how we feel strength-wise to how we feel emotionally.

Aaron   14:35

And having said that, when someone with MCS or TILT goes to a doctor and asks for help, and they're told that they have a mental illness or an anxiety disorder, how do you view that? 

Because we know that can cause a lot of distress, and alienation, and upset, right? Long lasting harm.

And is that just something that physicians do because they don't understand it enough?  As you say, we don't have enough insight into the physiological mechanisms that are at play?

Shahir Masri  15:06

It's tough to say. I think that our human minds try to fit everything into neat categories. It's how we process information. And when there's not a neat category, a medical category that we've been taught surrounding Chemical Intolerance, well, the only other category that maybe a doctor is aware of is a psychological disorder, and therefore, maybe that's why physicians often file them into that cabinet. 

Shahir Masri  15:38

It's also a potential that a lot of the physicians who encountered people with Chemical Intolerance are encountering such individuals at a late stage after, maybe, being turned down by physician after physician, who may be suffering for years on end. 

Shahir Masri  15:53

And I also, I don't think we can disconnect the extent to which such a grave, and debilitating, and frustrating experience – emotionally and physically – can actually wear one’s psyche down and potentially exacerbate the problem, because there's a definite relationship between our psychological well being and our physical health.

Shahir Masri  16:12

We know this from a range of studies, even looking at how people rehabilitate after surgery, who have an open window in their medical room versus staring at a brick building across the way. I mean, psychology does play a role in other aspects of physical health, wellbeing and healing. So it's possible that there's an interaction there between one's psychological health and more what we think of as physical, Chemical Intolerance sort of related aspect. 

Shahir Masri  16:42

And doctors may see some of the clearest psychological signs, and then conflate that or confuse that with what may have ultimately gotten them to that place – emotionally, physically and psychologically. So that may also play a role in why doctors are often sort of misdiagnosis diagnosing Chemical Intolerance

Aaron   17:06

I understand. And so maybe we can take a step back. You mentioned that you personally, as a researcher, prefer the term TILT, if I'm not mistaken, and maybe we can just unpack that a little bit. In your 2021 paper with Professor Miller and your colleagues, you write about a two-stage process, the initiation and the trigger. 

Could you please unpack that a little bit for us in the sense of are MCS and TILT the same illness? 

Is it the case where someone has MCS for an undefined period of time, and it's a progressive illness – with a question mark – and then it gets to a point where, what was once a sensitivity becomes an intolerance? How do you view all that? 

Shahir Masri  17:56

Yeah, it's a really great question. And the main reason behind this shift towards TILT – Well to answer your question there, yeah, they are basically the same thing. Multiple Chemical Sensitivity, Idiopathic Environmental Illness, Environmental Illness, Chemical Intolerance, TILT – these are all describing the same issue, the same public health issue going on within the population worldwide. 

Shahir Masri  18:23

The problem is that Multiple Chemical Sensitivity, for instance, MCS, describes a ‘sensitivity.’ And by the way, these earlier terms, with the exception of Chemical Tolerance and TILT, which is newer, these older terms have really come to have a real stigma associated with them in the medical community. They've often been, as you noted, associated or sort of discussed in the context of psychological health, dismissed as psychological disorders. 

So with Dr. Miller, her work has attempted to get away from these stigmatized terms that are embedded in an observation of illness without any indication of what's going on. So with her research, and her observations of a chemical induction of illness, she's gravitated toward the use – and this is over, over 20 years ago now – the use of the term Toxicant Induced Loss of Tolerances, which really more accurately describes what's going on.

Namely, an induction of an illness that is brought about through chemical exposures in the environment, and we can talk about what those are if you'd like. But that's just a really important point of clarification. There's a lot of terms out there floating how to describe a certain ailment. But we've sort of gravitated towards one that is more of a mechanistic description.  

Aaron   20:08

Right. And there is a lot of discussion among the community of folks with Chemical Sensitivity and TILT about what people feel is the best descriptor, right? I've read, and it's my personal view, that ‘sensitivity’ doesn't really convey the gravity or the severity of the illness to people. And some people can just potentially accuse one of being, well, ‘you're being too sensitive’, or it's just a mild inconvenience. 

And the term intolerance really hits the nail on the head. It describes, certainly, my experience and I believe a lot of others. It's not just a sensitivity, it is a profound intolerance.

Shahir Masri  20:52

I think so. And you point out a great point, which is sensitivity sounds almost blame-y. And ‘oh, well, you're just sensitive’, as you noted, and we need to, I think, get away from those terms that fail to recognize that there is an adverse exposure that is breaking down one's ability to tolerate that exposure. 

Aaron   21:18

Before we come to some of the common triggers, perhaps you could please talk a little bit about the range of symptoms that people with MCS or TILT experience? 

Shahir Masri  21:31

Yeah, sure. And before I talk about triggers, I'll just mention a thing or two about initiators. So when we talk about TILT and our understanding of Chemical Intolerance over the last several decades, what we tend to see is a two-stage mechanism. And this is described in our papers and other papers that Dr. Miller has published. 

Shahir Masri  21:55

Basically, you've got an initiation of Chemical Intolerance, and this is the initial chemical exposure. This can be a major initiation event, such as the remodeling of your building, which brought in new carpet and out-gassed a variety of chemicals that reached really high concentrations for an extended number of days. And ultimately, that was your initiation or your breakdown of tolerance to a variety of chemical triggers, which we'll talk about in a second. But it can also be low level chronic exposures over time. 

Shahir Masri  22:32

So these are the different ways that initiation can come to be. Once a person is initiated – again, thinking about it as their tolerance being broken down for tolerating everyday chemicals, foods, drugs. Once that's taken place, structurally diverse triggers can actually elicit symptoms, and it might not be the same chemical that initiated your chemical intolerance in the first place. 

Maybe it was a pesticide exposure, but because of that initial exposure event, you now are finding yourself unable to tolerate certain foods that you used to eat, certain medications that you used to take. Maybe you can't even tolerate your own home in the most severe cases. 

Most people don't realize it, but in your home, it's a real cocktail of different chemicals, particularly if you've got carpet and rugs and new furniture. If it's a newer house, you've got formaldehyde outgassing from the walls, from the compressed wood that's used to construct the home. So the chemicals available to trigger this kind of response are really countless in the indoor environment, which can make it really difficult for people suffering from MCS. 

Shahir Masri  23:46

Now, that's the two-stage mechanism. So you've got your initiation and your triggers. 

You mentioned symptoms that are quite numerous and can include anything from rashes, mood changes, difficulty with memory and concentration, also described often as brain fog, as well as respiratory symptoms. 

Aaron   24:08

Right, there is a long list and that's what I understand is part of the challenge that physicians have in being conclusive and giving a diagnosis. Would you corroborate that?

Shahir Masri  24:20

Yeah, when you're talking about acute symptoms, things like a rash for instance, a skin irritation, all the way to something like mood changes or difficulty with memory, this is quite a range of impacts, which lead most physicians to more question marks really than answers. 

Shahir Masri  24:41

So I think it’s understandable as to why physicians don't have a clear way, a clear path to handling these sorts of complaints, but it's, again, important to not discard these complaints. And that's just a really important message that we're trying to communicate to physicians. But it's not always easy to do so and there's, of course, physicians all around the world, hospitals all around the world. And the task at hand really is to convey this information to both patient and physician.

Shahir Masri  25:19

Many physicians, when you're talking about medical school – I mean, I've had many friends who are medical students – the curriculum is absolutely jam packed. There's very little room for really anything else. 

There is only a modest, minimal I should say, amount of even nutritional education that goes on in medical schools, and a very minimal amount of environmental health education. And somebody like me, my whole [teaching] curriculum is packed full of chemical exposure, environmental health courses, but that's all condensed oftentimes into a single course when you're becoming a medical student. 

Shahir Masri  25:58

It's somewhat akin to the field of chemistry, where most graduates of chemistry departments may never get even a single course in how to engineer chemicals that are not harmful to the environment and to public health. Because, again, the curriculums are so jam packed. So there's a real need for interdisciplinary teaching across these different schools of these different departments, because they all affect public health, but they're oftentimes disconnected. 

Aaron   26:31

And you write about, in your work and in your 2021 paper in particular, that there are certain groups who have been adversely affected by and developed MCS and TILT. For example, people who survived the attacks on the World Trade Center in 2011, people who've had implants, exposure to mold, exposure to pesticides, exposure to aircraft oil, among others. 

And without going into detail about the specific case studies, but for the general public, what are some of the major triggers that would lead one to develop this illness? 

Shahir Masri  27:18

Yeah, it's a good question. And, yeah, I won't go into those eight cases in detail, except to note that it's really important and useful to investigate and compare different groups who are affected by and developing chemical intolerance, following the same initiating exposure. 

So if you've got a roomful of people, as was the case in the EPA remodeling case that we noted from the 1980s, a whole roomful of people simultaneously were exposed to something and simultaneously developed a reaction – that's pretty strong evidence that there's something going on that is not just a random psychosomatic disorder. 

Shahir Masri  28:07

So what we did is looked at that across different populations who had had similar stories of chemical intolerance following shared exposures and compared them. And we did tease out a number of similarities related to what initiates TILT – pesticides being a main culprit, different VOCs or Volatile Organic Compounds. 

Shahir Masri  28:34

But in terms of your question about what triggers, after initiation has taken place, what triggers symptoms, we often see this can be fragrances. So this can be things ranging from just perfumes to odors that one might encounter after cleaning their house. So chemical solvents, the things that you clean your floor with, traffic exhaust, diesel emissions, oftentimes noted, foods. 

Sometimes somebody's favorite food is no longer – it couldn't be further from a favorite anymore. It actually becomes something they can't tolerate and causes the symptoms to be elicited, the types of symptoms we talked about before.

Shahir Masri  29:19

Alcohol and caffeine often come up specifically. Red wines are often mentioned as the types of foods that are no longer tolerated once somebody has become initiated. And reports – I  get emails from time to time in my inbox of reports – by people who are the most severely Chemically Intolerant often are describing their homes really as no longer even being tolerable. 

Likely for the reasons that we talked about earlier, all the different chemicals that are in the homes, and it's not always easy for that reason to identify the specific triggers that are causing somebody to become symptomatic. Walking in your home, you're immediately hit with a wall of dozens of different chemical exposures. So there's still some, a lot that remains to be understood about what specifically causes people's symptoms. 

Aaron   30:14

One thing that comes to mind in listening to you Professor Masri, is why do some people develop MCS or TILT and others do not? So you noted that people, for example, in a case where there's severe exposure to a chemical that creates the onset of the illness – but let's say, a library that I frequent is remodeled. 

Why would, for example, 10 people develop MCS and 10 wouldn't? Is it because of genetics? Are some people predisposed to developing it? I've heard it described as, not a malfunction, but a problem, for lack of a better word, with one's genetic makeup. 

Shahir Masri  31:02

Yeah, so we know very well and toxicology knows this extremely well – the field that deals with toxicological impacts and the actual biological mechanisms that ensue during the body's breakdown of chemicals, or what's called Bio Transformation reactions that take place in the body.

These are the ways in which the human body actually converts harmful chemicals into more benign chemicals that can then be processed and excreted. So these bio transformation pathways in the body vary from person to person. There's some very common ones that , for instance, get followed when you drink caffeine. Certain enzymatic pathways that lead to the breakdown of caffeine, but there's about 13 or so different pathways that it can actually go down when you're breaking down caffeine. So we know very well that the human population, there's a lot of genetic diversity. 

Shahir Masri  32:03

And there's a lot of different susceptibilities to different compounds, different exposures, even communicable diseases. Somebody may fare better than another person who both get impacted by the same virus. Now, those are different reasons. But in the case of chemical intolerance, it's these enzymatic pathways that are really important to rendering a person either resistant to or very susceptible to a given chemical insult. So that's really the story that explains diversity when it comes to chemical exposures – diversity in terms of how one responds.

Shahir Masri  32:47

There's a common phrase, ‘it's the dose that makes the poison.’ 

And that's true, but a more accurate term that we've come to understand over the decades of environmental research is, ‘it's the dose plus the host that makes the poison.’ 

Not only is it important as to the concentration of exposure, but it's also important as to your biological makeup – the types of enzymatic pathways that can be followed and the types of enzymes you have in your body that can break down certain chemicals. And when we talk about occupational exposures, there's actually something called the healthy worker effect. 

Shahir Masri  33:23

So if you go to study a group of people working in a certain industrial facility, you are likely to be dealing with a rather tolerant bunch of people because the people who were not able to handle those kinds of exposures, they got sick after a week or two, or a year, and they quit their jobs. So we know very clearly that there's a whole range of different resistances to different chemicals that are out there in the population. And that's the same thing for Chemical Intolerance. 

So it's going to vary from person to person, due to enzymes and other genetic factors. 

Aaron   34:02

Just shifting gears a little bit, when people with MCS or TILT try to explain their illness to – whether it's loved ones or friends, colleagues and even doctors – do you have any tips for what folks can say?

Because we want to be believed, we don't want to be met with denialism, or skepticism or suspicion or be gaslit. What can we say when we're met with this?

Shahir Masri  34:31

I'm a big proponent of references and citations. And I think that's what the world comes to, values for good reason. So whether you're talking about a news article – saying that you read it from the New York Times is more persuasive than saying you read it on somebody's blog posts. So the same is true if we're trying to convey that there's a real problem that's credible. 

I think it's important to bring your physician some peer reviewed papers. That is the highest bar of credibility in a scientific field, is a peer reviewed paper that describes the situation. 

Shahir Masri  35:15

Our team that I work with, with Dr. Claudia Miller, we're a strong team that has brought in academics from MIT to Harvard, UCI, Texas. And those are all points of, I think, credibility that will help a patient convey to a physician, ‘look, these are papers that are coming out of top universities that are showing this real problem that's out there in the field. I'd like it if you could review this, to better understand what fits my description of health outcomes.’

Shahir Masri  35:53

So I really encourage people to print out a couple of our papers, take the QEESI, and then bring this stuff to your doctor. Don't bring too much. If you bring a giant stack of papers, it's going to likely go unread, but if you just select a couple key papers. I would encourage someone to pick up our recent paper, which is available at the tiltresearch.org website. It's also on my website, shahirmasri.com. 

You'll be able to print that out and bring it to your physician, and that I think is going to be a really important way to convey the science behind what's going on.

Aaron  36:30

And that's very helpful. We will certainly provide links for listeners on our platforms.

Shahir Masri  36:35

It's not possible to have a paper that is the gold standard. And so by no means is our paper the end all story, it's really about the preponderance of scientific evidence, and that's going to grow over time. There's a few papers that can be out there, citing climate change not occurring and those papers aren't really important because we've got thousands of other papers that say the contrary. 

Shahir Masri  37:00

Now, in the case of Chemical Intolerance, we're unfortunately not graced with this wide, giant abundance of papers on Chemical Intolerance. But we do see a growing trend in literature. And that's important. But the point of bringing a paper for your doctor is not to say that no other paper out there is able to refute what we're finding, it's just to provide a scientific basis to help your physician understand what's going on. 

Shahir Masri  37:31

It's not easy, necessarily, for doctors to keep on top of every single disease and how it's transforming in the scientific literature. So what you're doing is you're just helping your doctor to better understand your problem. And it's not easy to change an entire medical community overnight. 

It's not going to happen overnight. But it is an important starting point. 

Shahir Masri  37:54

And related to the strong countervailing winds that do exist, that are going to make it difficult to shift the medical paradigm over time, it's worth noting that funding plays a major role in terms of what is studied. And there's not a whole lot of funding to investigate this line of work. When you think about the solution to this problem, maybe there's some treatment that, down the road, will be discovered, but for the most part, it's pretty much reducing chemical exposures. 

What does that mean? It means you're probably not going to get a lot of large funders. So we see this kind of this challenge related to funding play out all across the world, different universities, and it's not easy to get funded for research that ultimately is going to bode poorly for the funder. 

Aaron   38:47

Understood. But it's encouraging to hear you say – I think I heard you say – that the research will catch up. That, over time, there will be more. And do you have a sense of roughly what percentage of the population is affected by MCS and TILT? And are you seeing a growing number of people? And how do you see the future unfolding? 

Because from what I gather, a lot of your research focuses on climate change, and do you see any parallels there as the world gets hotter? Or parallels as it becomes more polluted? Are we going to see a ramping up of this illness and in tandem, is your hope that more research will be done?

Shahir Masri  39:40

So it's a great question on the percentage question. Double digit percentages  are commonly referenced in terms of the percent, but it's difficult to put a number on it just because the severity of chemical intolerance can differ so dramatically. And one study might have to refer to the most severe cases, whereas another one is just referring to different elements that might come from fragrances – maybe unpleasant, short term reactions. 

So we see percentages as high as 30 or more percent. But certainly that's a high number, if we're thinking about severe cases. But it's very prevalent, I guess would just be the short answer from what we can gather from the literature. 

Shahir Masri  40:25

In terms of the problem growing over time, I think that's a real big concern. 

We saw this in the 1970s, during the oil shock, when buildings got tighter to reduce the energy needed to heat and cool buildings. This led to an increase in indoor air pollution because tighter buildings that aren't as leaky to outdoor air also mean there's an ability for chemicals to sort of accumulate inside. And that was a negative for indoor air quality. We may see that kind of continue, as energy conservation becomes more important. But the other thing to note is that climate change, the impacts from climate change are also worth noting. And we're hoping to write a paper soon to showcase some examples. 

Shahir Masri  41:12

But there was a paper I wrote, an article that was published in The Hill in 2016, which talked about the hurricanes that were slamming the Gulf Coast. And what often happens afterwards is you get massive flooding events, you get a lot of resurgence of mosquitoes and breeding as you get a lot of stagnant pools. And what this ultimately leads to is regular aerial spraying, using pesticide across the Gulf Coast. 

Shahir Masri  41:40

So a situation like this, if we're going to see increased hurricane severity across different regions of the world, it's expected that we may see an increase in pesticide related cases of Chemical Intolerance. So that was just one example. But there's other examples like that, and I think climate change is going to just pose a challenge. Another one might be wildfire related Chemical Intolerance, we don't actually know a whole lot about Chemical Intolerance that’s initiated by wildfire smoke. 

Shahir Masri  42:10

But that's just another plausible reason why Chemical Intolerance may be a growing issue moving forward. Hopefully, with this literature growing and a better understanding of this issue, we can see policy and other important interventions to reduce chemical exposures in the sort of synthetic world, to engineer products that are less prone to outgassing. We've seen paints now that are low VOC paints. And that's a good step in the right direction. And hopefully, we'll see more of that over time.

Aaron   42:45

That's really an optimistic note. 

And lastly, what's on your radar, in terms of MCS and TILT? You mentioned some issues related to the heating of the planet, etc., but are there any other questions that you're interested in that give us a little window into what's going to motivate you going forward? 

Shahir Masri  43:11

Yeah, so my interest in both the field of air pollution and also MCS are kind of converging under this umbrella of wildfire impacts and climate change, so that really actually does encapsulate some of what I'm interested in examining moving forward. 

We've had a couple of papers published now, looking at – well, one of them was published and the other one is being processed – at the impacts of wildfires across the state of California. So I am interested in ultimately taking that into the domain of chemical intolerance. We haven't done that yet, but it's something I'm interested in. And climate impacts broadly is something that I'd like to investigate as it relates to Chemical Intolerance. 

Aaron   43:53

I've heard anecdotally from folks with MCS that their illness was triggered by exposure to wildfire smoke. So that's probably something you're certainly familiar with, I'm sure.

Perhaps, lastly, we tend to talk from a North American perspective, but when you look out at the world, are you seeing sort of similar rates? Are you aware of similar rates? I read that, for example, in Japan – I think it was in your paper – there's been a significant increase over 10 years. Now, what do you see in terms of a global picture in terms of prevalence of the illness?

Shahir Masri  44:34

Yeah, it's a good question. And the answer is, we're always trying to learn more. 

There's been a trend, or a hypothesis I should say, that the developed countries are affected by this more than the underdeveloped countries, due to a lot of the exposures that we encounter in our very developed society. With lots of products and commodities that are filling up our households that emit chemicals, but it remains to be seen how this looks in some of them are underdeveloped countries. A lot of the research, as you can imagine, comes out of the developed world. 

So we're launching a survey that's looking at several thousand people. We haven't done it yet, but it's probably going to be a six nation study that's going to survey at least 1000 people from each country. That's going to include both underdeveloped and developed nations. I think we're including India as one of the countries. So we're going to be very curious to see what the prevalence of Chemical Intolerance looks like across these different studies. But we don't totally have the answer at this moment.

Aaron   45:54

It's just been really fascinating listening to and speaking with you, learning more about your work, and I think people who listen will really benefit from hearing from all the knowledge you've shared. Just on a personal note, it's quite moving to hear you speak and to hear your commitment and your passion and your expertise. So I really want to thank you for the work you do. 

Professor Masri once again, thank you so much. 

Shahir Masri  46:23

Absolutely. Well, thank you – a big part of what we talked about on this podcast was the need for outreach and communication and ultimately shifting of the current paradigm. So you're playing a big role in that yourself with this podcast, and I know you’re a professor and are doing great work as well. So thank you very much.

Aaron   46:41

That brings us to the end of this episode of the Chemical Sensitivity Podcast. Thank you to Dr. Shahir Masri for joining me. 

The Chemical Sensitivity Podcast is produced by me, Aaron Goodman, and Dani Penaloza and Emma Bolzner. To learn more about the podcast and to hear more episodes, please subscribe wherever you get your podcasts. Leave us a review and share the podcast with others. Follow us on social media just search for the chemical sensitivity podcast or podcasting MCS. Email me at info at chemicalsensitivitypodcast.org I'll definitely respond. 

Thanks so much for listening.