Public Health

PFAS health effects and CDC guidelines on how to reduce PFAS exposure with Aaron Bernstein, MD, MPH


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Where do PFAS come from? Can you get rid of PFAS in your body? In this episode, the CDC covers PFAS products, forever chemicals in food, how to avoid PFAS and what physicians need to know about PFAS symptoms.

Our guest is Aaron Bernstein, MD, MPH, the director for the CDC’s National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry. Dr. Bernstein also shares guidelines for physicians on when to test for perfluoroalkyl, or, per- and polyfluorinated substances, PFAS in patients and how PFAS exposure can be harmful. AMA Chief Experience Officer Todd Unger hosts.


  • Aaron Bernstein, MD, MPH, director, CDC’s National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry

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Unger: Hello and welcome to the AMA Update video and podcast. Today, we're discussing what physicians need to know about PFAS. What's PFAS? Well, our guest today is Dr. Aaron Bernstein, the director for the CDC's National Center for Environmental Health and Agency for Toxic Substances and Disease Registry in Atlanta. He's going to give us all the background that we need to know. I'm Todd Unger, AMA's chief experience officer in Chicago. Dr. Bernstein, thanks so much for joining us today.

Dr. Bernstein: Thanks for having me, Todd.

Unger: Dr. Bernstein, the CDC recently released a new guide for physicians with updated information about PFAS. What prompted the CDC to issue this guide? And what's the main takeaway in it for physicians?

Dr. Bernstein: The main takeaway, Todd, is that we can be more helpful, more helpful than many of us may realize, for our patients who are concerned about PFAS exposure. And it was the voices of communities around the United States that really pushed us to issue this new information to help support decisions that will make sense for individual patients in clinics around the country.

Unger: Well, I'm sure there's a lot of information that folks need. They may not be familiar at all with the concept or the idea. So let's start by talking about some of the information in the guide. Well, begin, of course, by telling us what PFAS are and where they're found.

Dr. Bernstein: So there are thousands of PFAS chemicals. They've been branded "forever chemicals" because many of them last for decades, if not centuries, in the environment. But in the United States, there are really four—I call them the big four—that are in most people. Those are PFAS, PFOA, PFNA—those are what we tend to find in non-stick pans, stain-repellent clothing and the like. And then the fourth is PFHXS, which is in firefighting foams. And that's the one we tend to see in communities that have been around particularly airports where firefighting foams have been sprayed to either put out fires or to practice putting out fires.

Most people in the country are exposed to PFAS through drinking water. But there are many communities that have had production facilities for PFAS that have gotten PFAS into their bodies. Some of those facilities don't make the big four. And so those communities are a little different. Farms have been contaminated with PFAS because sewage sludge that was contaminated with PFAS was applied to the farms. And the food grown on those farms could have PFAS in it.

And then there are other sources of exposure that are maybe more common for many people. Food wrappers that are grease-resistant, often on fast foods, your hot dogs, pizzas—a lot of those wrappers have PFAS to keep the grease from leaking through. And there's just a whole bunch of consumer products that are stain-repellent, water-repellent or particularly slippery—some dental floss, for instance—that have PFAS in them.

So those are the main—again, the main four are—or the big in most people. The most common route of exposure in the United States is water.

Unger: So listening to that list of sources that you just outlined, I'd call that pretty pervasive. And as you know, PFAS are a growing concern for patients. What are some of the reasons that we should be concerned with increasing levels of PFAS in our environment and in our bodies?

Dr. Bernstein: So we know, Todd, from data collected at CDC over decades now that the good news is that as a nation, our levels of those big four PFAS have been going down. That needs to be separated from communities where PFAS has been a hotspot issue. Again, these tend to be where there are airports or factories, where we see farms, again, being contaminated. And these pop up. And those communities' levels go very high very quickly.

And we are learning more and more every year about the effects of PFAS on our health. And so understandably, communities where there is new exposure or ongoing exposure—there's concern.

Unger: What are some of the known health impacts of exposure to PFAS? In what cases should a physician be testing for that kind of exposure?

Dr. Bernstein: Great question. So right now, the evidence we have, and we reviewed the evidence here at CDC—we also work with the National Academy to have an independent review of the evidence. And right now, the evidence links PFAS exposure to higher cholesterol, lower birth weights, kidney and testicular cancer, high blood pressure in pregnancy and preeclampsia, and liver inflammation. There are other health conditions where there is some evidence. But it's a bit more uncertain. Particularly, thyroid disease is in that list.

And so understandably, people who live in communities where there's known exposure in the water or through other means are asking to be tested. They want to know their exposure. And in our information for clinicians, we try and provide knowledge that will help make informed decisions about testing.

So let me walk through, hopefully, some good steps that providers can take with their patients to make sure that when we do testing, we do it in a way that's going to be really helpful. The first is we've got to do an exposure history. Let's ask individuals about, do you know you've been exposed? If so, how? Do you work in a factory or do you live near a factory where PFAS is manufactured?

And we have all that information available in our information for clinicians. Some communities will also be very well aware, for instance, of testing of water supplies in their community and know that there has been exposure.

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So if you know someone has been exposed, either through water source or any source, we ask clinicians to really think about how a blood PFAS level can inform reducing exposure or health promotion. So you can imagine a person living in a community where there's been lots of water contamination known. And that individual might want to know whether they've been exposed because, for instance, if they haven't been exposed, they might breathe a sigh of relief. They might say, boy, I'm OK here. Of course, they may also know they've been exposed. And that's why taking the exposure history is so important.

There may be instances where someone is pregnant and may want to breastfeed. They want to know if they've been exposed to have high level because we know that PFAS gets into breast milk. And many individuals may be concerned about that, even though our evidence isn't definitive, by any means—about the health risks in infants. But surely, I think many people would be reasonably concerned.

And there are other reasons. Cholesterol—we talked about cholesterol. There are many communities I know where firefighters have been heavily exposed. Firefighters do great work for our communities. They often don't take care of themselves. In many cases, I've heard from providers that the first time they've seen a firefighter in their office was a concern for PFAS exposure.

If they haven't reached an age where routine cholesterol screening might be appropriate, you might consider both screening for cholesterol and a PFAS level in part for that individual and others to know if they're reducing their exposure—in that case, occupational if they can—not always possible—or maybe through a consumer product—someone's been using nonstick pans—they get rid of them—to see if their levels go down. So that could be another reason.

So the last thing I'll say in terms of testing—make sure—if we're going to send a PFAS test, we're sending it to a CLEA-certified lab. The good news is that there are more commercial labs around the country, some of them national, that are starting to offer PFAS testing. There are diagnostic codes, testing codes that are readily available. And we're seeing more and more insurers, major insurers, covering PFAS testing as a routine test in individuals who've been exposed.

So again, the point with testing is let's make sure we understand that we're doing a test for a good reason, that we're doing it for the PFAS that an individual is known to be exposed for. Remember, most people are exposed to the big four. But in some communities, that might not be the PFAS that an individual has been exposed to. And let's make sure that the lab that's testing for the PFAS is CLEA-certified and is testing for the right PFAS.

Unger: All of those things make sense. Those are great guidelines. Dr. Bernstein, if a patient that undergoes this kind of testing is confirmed to have high levels of PFAS in their blood, is there any treatment that their physician can provide?

Dr. Bernstein: So the bad news here, Todd, is there is no medically approved treatment to remove PFAS from the body. And so that really gets back to how important it is to start with the exposure history and try and reduce exposure whenever we can. It may be appropriate to consider whether additional screening is helpful. I talked a bit about cholesterol. Thyroid screening may be appropriate. But let's ask the questions first before we pursue testing. So let's figure out the family history of cholesterol, the individual's personal risk for high cholesterol, their symptoms of thyroid disease, do an exam.

And I think it's important to remember that while there have been thresholds proposed, including by the National Academy, for instance, who recommended that over 20 nanogram per milliliter PFAS level—and that's the aggregate level of the big four—that clinicians might consider pursuing cholesterol testing and a TSH. Remember that many folks were exposed years ago. And their levels may be lower.

And so I would be careful about using definitive cutoffs right now and, again, start with a history of—and this is why knowing the disease associations is so important in the context of an individual's health history about what tests might be appropriate. And of course, we already have screening guidelines for things like cholesterol, certainly for blood pressure and pregnancy. And so we need to think about the individual's history, their exposure history in particular, their unique health history, and whether or not the PFAS level should dictate further management independently or whether we should be taking histories for the diseases that are known to be associated with PFAS exposure and work from there.

And I think our information really tries to get providers to realize that PFAS levels can be very helpful, particularly around exposure reduction. They can certainly trigger incentives to screen. But we want to make sure that providers understand that just because someone has a level that may be lower than the nation's threshold doesn't necessarily mean they're not at increased risk because they might have reduced their exposure long ago, but still been exposed. And again, we really just want to make sure that people understand the risks and benefits that come with testing, just like any other test.

Unger: Well, speaking of reducing exposure to PFAS, what advice can physicians give to their patients toward that end?

Dr. Bernstein: Sure. So as I mentioned, the main source of exposure is water. Many people in the country are municipal water supplies. And it's important for providers to know that EPA will likely be putting forth new rules that will not only require municipal water systems to be testing for PFAS, and many systems already are, but also, of course, set a standard which is intended to protect health of the levels of the big four and a few others that may be in the water.

And so from that standpoint, I think we've seen lowering levels across the country, already. I think the protections that are going to come from EPA—and by the way, USDA is also interested in addressing this with sewage sludge, among other risk exposure. So I think in that sense, being aware of that, at least in the back of one's mind, is important because the alternative for water filtration can be very expensive for individuals, and in many cases, hard to do. The filters that filter out PFAS are not necessarily standard activated charcoal filters you can buy off the shelf at a big-box store. And they can be expensive, hard to use. And they need to be maintained. But it is possible. People can do it.

For other sources of exposure, the nonstick pans, again, people can switch out their pans. They can get clothing that isn't coded—if you see a piece of clothing you can buy, don't bring clothing into your house that has stain resistance, water resistance on the label. And we have in the information a whole list of areas that people can work on exposure reduction beyond those two.

Unger: Dr. Bernstein, thank you so much for sharing your insights with us today. We're going to include a link to that full PFAS guide and more resources from the CDC in the description of this episode. If you found this discussion valuable, you can support more programming like it by becoming an AMA member at

That wraps up today's episode. We'll be back soon with another AMA Update. Be sure to subscribe for new episodes and find all our videos and podcasts at Thanks for joining us today. Please take care.

Disclaimer: The viewpoints expressed in this video are those of the participants and/or do not necessarily reflect the views and policies of the AMA.

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