Is Environmental Exposure Another ‘Piece of the MS Puzzle’?

Large numbers of multiple sclerosis (MS) patients appear to be clustered in southeastern Wisconsin, and researchers are trying to find out why.

At a platform session at the recent Consortium of Multiple Sclerosis Centers (CMSC) annual meeting, a team presented healthcare records showing densities of MS patients as high as 1,000 cases per 100,000 persons in some Wisconsin zip codes — about three times the norm of 353 per 100,000 population in the Midwest.

In this exclusive MedPage Today video, senior author Ahmed Obeidat, MD, PhD, of the Medical College of Wisconsin and Froedtert Hospital in Milwaukee, discusses the findings of the observational study and offers his explanation of the results.

Following is a transcript of his remarks:

What we really noticed is, in our clinic that there are frequently people coming from certain areas in the state of Wisconsin, and these areas are not really very close to the MS center. So they’re driving a distance to come in, and we frequently see these patients coming in and kind of hear that there are many patients who live with MS in the neighborhoods in the areas around them. People know many people who also have MS, who maybe went to the same high school or things like this. So, we thought is there a cluster of MS cases in certain areas in Wisconsin?

So this is really what triggered the actual study. So it was more of a clinical observation in our own clinic, where we thought there might be some clustering of MS cases in Wisconsin.

When we did the analysis, what we’ve done is we’ve looked at patients in our system. So we’re called the Froedtert and Medical College of Wisconsin Healthcare System. So we looked at patients who are receiving care in our system at any of our locations who have a diagnosis of MS.

And the idea is, we are actually underestimating the numbers because we’re only looking at people in our healthcare system, right? So not everyone with MS is actually coming to see us. Some people go to other healthcare systems in the area. There are many other large healthcare systems in the area. So when we thought about this, we said, okay, people who are coming to us, to our healthcare system who have a diagnosis of MS, we want to see their numbers and calculate density based on the zip code.

So when we did this, actually, we had really surprising results, because even with underestimating the numbers — because we were only looking at one healthcare system — the numbers in some areas were over 1,000 patients per 100,000 who actually from a density perspective have MS. This is about three times, at least, the average of the area as we think from the most recent data on the prevalence of MS.

So we also saw this proportionality; we saw that some areas have more patients who have MS than other areas.

And this is kind of interesting, because when we looked at the environmental kind of allocations and what else is there? And we had actually a little theory here because we thought could people have anything to do with some manufacturing, something in the environment, maybe a chemical, maybe a toxin, maybe something like this?

So what we found is that there are certain areas where there are clusters of MS that are also in very close proximity to aluminum factories. So that’s kind of something of interest, because we looked in the literature and we see that there are some prior descriptions of high, I would say concentrations of, aluminum in the brains of people with multiple sclerosis, maybe with other diseases that are neurological.

But also what grabbed our interest is, aluminum, we call it an adjuvant for vaccination in a way. When we want to trigger the immune system, when we want to trigger the immune response, we actually can use aluminum to help trigger the immune response for something good, like vaccination. We want to get excellent response to the vaccine, so we trigger the immune system.

But we thought in a way, could this be something in the environment, where maybe it has to do with aluminum, maybe something else that maybe is triggering the immune system in patients who may be predisposed to have MS, or to develop MS? We know it’s a multifactorial disease, right?

So the recent data that we’ve seen is mostly focused on Epstein-Barr virus [EBV] as a possible cause of multiple sclerosis. There is now strong epidemiological evidence to suggest that Epstein-Barr virus or the mono virus is actually a leading cause of multiple sclerosis.

So the remaining question is why some people who get EBV infection, many of us do not develop MS, only a few people develop MS. And also the remaining question is why people with certain genetic predisposition, even monozygotic twins, people who are exactly the same copy of genetics, if one twin has MS the chances for the other twin to have MS is about 30%. So there’s about 70% environmental factor there, right?

So there are several pieces of the puzzle. You know EBV is one piece, genetic is one piece, low vitamin D is one piece, smoking is one piece. Many others. Now we are thinking, could there be something in the environment that’s another piece? To kind of fill that story up. Is there something that may trigger the immune system in certain individuals who are susceptible to have MS? And the question we had is could this be something like aluminum or aluminum byproducts?

So this is just an observational study. It’s a start. Now we have to examine further, I would say. So we have to look more to look really more into the clustering itself. We can maybe do some interviews. We may actually do some environmental testing. So we are kind of opening this arm of study to further investigate.

The cause of MS is still a mystery. And I think, we are becoming a step closer. With EBV a step closer, with low vitamin D, with genetics. And now maybe with some environmental exposure, that will be another factor that we can add to it.