So Amber, you recently published a study which found that using certain products during pregnancy, like makeup, lotion or nail polish, can expose babies to dangerous chemicals. What brought you to that subject?
Hall: I grew up near a chemical company. It was five minutes away from our home and we would drive by there every day. And when you have these giant smokestacks and you see stuff being emitted every day, I think the next natural question is, what is that? And is that okay?
After working in a hospital for a while, I realized I wanted to make a bigger difference at the population level, doing more population level science, which is what led me into epidemiology.
So instead of patient by patient, you wanted to make an impact on a whole population of people.
Exactly. Biostatistics is one of the first things I fell in love with. I loved the idea that one person can tell you something is wrong, but then when you have a hundred, and sometimes a thousand people volunteer their time so that you have the opportunity to say X is associated with Y, or we do see an association with these chemicals and this health effect. That can make a really big impact.
Which led you to look at PFAS. What are they, exactly?
PFAS is an acronym and it stands for per- and polyfluoroalkyl substances. And this is a very large chemical class, so a bunch of different types of chemicals. They're known for their oil, water, and heat resistant properties. So things that are water resistant, stain resistant, heat resistant, nonstick surfaces like Teflon pans, for example, things of that nature will often contain PFAS.
We're worried about them because we have found associations with a lot of different health effects: Kidney and testicular cancers and different thyroid disruptions for example. In children it's been associated with decreased vaccine response, low birth weight. And then also, it takes a really long time to leave our bodies. A lot of chemicals we're exposed to, they leave within a matter of a few hours or a few days. With PFAS, it takes several years.
How widespread are these chemicals?
PFAS have been found on all seven continents, including Antarctica. So they are very widespread and they are considered ubiquitous, which is a fancy way of saying simply they're everywhere. They have been found in the blood of 95 percent of the U. S. population, and that is only testing for four of the PFAS compounds.
Additionally, studies have found that PFAS can be transmitted through the placenta. So during pregnancy, if a pregnant person is exposed to PFAS, that can then go through the placenta and reach the child. And pregnancy is just such a sensitive window of development. You have so many things that are happening, so many processes that are occurring to create a human being that disruptions during that time can often have a greater impact than they would if you were exposed later in life.
So when you found out that PFAS were used in items that pregnant people might use like makeup, hair dye, nail polish, perfumes and lotion, what did you do?
Well what we didn't know was whether or not exposure to PFAS from these products was actually getting inside of us. And that is the question that this study really set out to answer.
So we gave our subjects questionnaires at four different time points, and many of those questionnaires didn't just get at do you use the product, but how often do you use the product. Whether or not you never use it, you sometimes use it, or you frequently use it. So we could get at whether or not these usage habits were impacting their PFAS concentrations at specific points in time.
What we learned was that many of the items that we tested we found that higher use of these items was associated with higher PFAS levels in both blood and the human milk.
