Toxins in the Environment

Adrienne S. Ettinger, Sc.D., M.P.H., studies early life environmental exposures and the effects on maternal, fetal, and child health. Her research involves the epidemiologic analysis of environmental exposure to metals, such as lead, and the associated human health effects in several new and ongoing longitudinal birth cohort studies being carried out in the United States and other countries. This research may provide insights to better understand how environmental risks vary within and between populations with respect to exposure, underlying susceptibility and developmental stage. She is trained as an epidemiologist with interdisciplinary training in biostatistics, environmental health, and biological sciences, including molecular biology and genetics. Her background includes significant experience with community-based epidemiologic research and public health program implementation. This experience includes working in the federal government with state and local public health departments, conducting academic research in both urban and rural settings, and working with diverse, multi-ethnic populations both in the United States and internationally. Dr. Ettinger joined the School of Public Health in 2010 as an assistant professor in the Department of Chronic Disease Epidemiology. She is also affiliated with the Center for Perinatal, Pediatric, and Environmental Epidemiology.

You study the health effects of exposure to chemicals that people come into contact with in their environments. In particular, you have done a lot of research on lead poisoning. Does lead poisoning remain a serious problem in the United States?

AE: Lead poisoning prevention has been hailed as one of the top public health and the top environmental health success story in the last 50 years due to regulations aimed at removing lead from gasoline and household paint. While the general U.S. population does not have to worry a great deal about lead exposure any more, there are still significant numbers of people in this country at-risk from the harmful effects of lead.

Can you provide an example?

AE: Yes, young children who live in older homes that have not been well maintained may be exposed to lead in paint chips, dust and soil. They are particularly vulnerable because they spend a great deal of their time on the floor and putting their hands in their mouths and their normal body functions are still developing. In addition, they may have other risk factors, such as inadequate nutrition, for their bodies to block lead absorption.

What about lead exposure in other countries?

AE: In other countries, particularly in developing countries where regulations may not be in place, there are still sources of lead exposure. For example, children were recently dying in large numbers in Nigerian villages and lead, involved in the process of mining gold, was identified as the cause of a widespread “outbreak” of childhood lead poisoning. There is plenty of work still to be done on removing environmental hazards from the environment and preventing human exposures from occurring in the first place.

So, how dangerous is our environment in terms of its possible health effects?

AE: The “environment” has received increased attention in recent years due to our improved ability to measure biological markers of exposure, in people’s blood or urine, for example. This has raised our awareness that we are all exposed, on a daily basis, to a myriad of chemical, biological, and physical agents that we do not always sense in our environment or surroundings but, nonetheless, may have potential adverse health effects. We are only now beginning to scratch the surface of the range of potential health effects that may be associated with low-dose, chronic environmental exposures. But, it is also very difficult to avoid contact with the air we breathe and the water we drink. I believe this leads to frustration and a feeling of helplessness among individuals and why strong laws and regulations controlling environmental pollution are so important.

What about pregnant women? Are they and their babies particularly susceptible to environmental hazards?

AE: Yes, in fact, new research suggests that many chronic diseases, representing a significant public health burden, may originate in or be triggered by changes in the intrauterine environment. Environmental factors, particularly the so-called “endocrine disruptors” – that can mimic the actions of the body’s own hormones – likely play a role in this phenomenon, but it is still very early in this research to say definitively that this is so.

What can expectant mothers do for themselves and their unborn babies?

AE: Again, it is difficult for individuals to control all that they are exposed to in their environments but, in general, pregnant women should maintain a healthy diet to improve their body’s ability to prevent absorption of environmental toxicants. On the flip side, fruits and vegetables, which are part of a healthy diet, contain pesticide residues which may be harmful, so it is important to wash produce thoroughly and buy organic (pesticide-free) whenever possible. Also, pregnant women in particular should be careful when working in jobs that may put them in contact with harmful substances, or even when remodeling their homes, and discuss any potential environmental exposures with their doctor.

You have done some work with arsenic. How dangerous is this substance and how do people come into contact with it? Is it commonly found in the environment?

AE: Environmental health is like real estate: it’s all about location, location, location. Arsenic is a perfect example because, although it is a naturally occurring element in the Earth’s crust, it is only a problem in certain locations where the conditions are right for human exposures. Mainly, we come in contact with arsenic through these naturally occurring sources in drinking water, but there are also other industrial and agricultural sources that may contaminate water, soil, and air.

Can the adverse health effects from exposure to environmental hazards be reversed?

AE: Unfortunately, no. Most of the health effects that can actually be causally linked to environmental exposures are not reversible. That is why prevention is so important. Another problem that I have hinted at here is that many diseases and illnesses are multifactorial – in other words, they have many causes. It could be that environmental exposures are just one piece of the puzzle in disease causation and it is not always easy to find the “smoking gun” or prove that the environment caused a particular disease or illness.

You also study gene-environment interaction. Is that what you’re getting at?

AE: Yes, partly. It is becoming increasingly common knowledge that it’s not just the genes you are born with, or the things you are exposed to in the environment, but a complicated set of interactions between the two that is involved in the development of most common chronic diseases. Here I am referring to the “environment” in broader terms—to include things like diet and socioeconomic factors, for example.

Some of your work is focused on the Navajo Nation. What are you finding?

AE: I have been involved with several research projects involving Native American communities in the United States. The Navajo Birth Cohort Study, being led by my collaborators at the University of New Mexico, is just getting started, so we won’t have any results for many years. But, since we are talking about the environment, I would like to point out that I appreciate the Native American sentiment that “We do not inherit the Earth from our Ancestors, [but rather] we borrow it from our Children.” It is a very simple, but profound, message for the environment and public health.

In terms of environmental health hazards, how does the United States compare to other countries?

AE: Environmental health issues in the United States, and globally, are politically motivated. Some of the biggest polluters in this country are large corporations with a lot of influence.

The U.S. government has enacted some far-reaching measures to protect the environment and, as a result, peoples’ health. Does more need to be done?

AE: Yes.

What do you see as the biggest current environmental threats to human health?

AE: I believe that the biggest current environmental threat to human health is not a specific toxic chemical or compound, but the lack of pollution control and the ability to hold polluters accountable for their actions. We cannot do a lot to prevent past exposures, but we can learn from them, and work to improve our future health and that of future generations. “The earth does not belong to man; man belongs to the earth.”