Understanding the Exposome

Q&A with Paul Juarez

by Bradley Gao

Dr. Paul G. Juarez is professor of preventive medicine and director of the Research Center on Health Disparities, Equity and the Exposome at the University of Tennessee Health Science Center. He spoke with Bradley Gao about how his research is utilizing community-focused data to impact underserved communities, and how understanding the “exposome” is crucial to public health.

Bradley Gao: What is the Research Center on Health Disparities, Equity, and the Exposome, and how did you come to lead it?

Paul Juarez: My career trajectory started in Los Angeles. My first job there in academic work was at Charles Junior University of the King Jude Medical Center, where a lot of my research was in youth violence prevention. Working with physicians in the ER and surgery department, I became aware of the impact that homicide was having on families, and I talked to the social workers about what they were doing about it. Their response sort of shocked me: there is too much to do anything about it. All we do is discharge work. So I helped to start a support group called Loved Ones of Homicide Victims. We got together a group of social workers and therapists to provide counseling to families, individuals, and children. When I got more involved in meeting families, I could see the total devastation it had in their lives. I really wanted to have an impact.

Fast-forward about 10 years later: the Center for Disease Control put out a request for youth violence prevention centers in Nashville. From there, I began to look at violence in terms of poverty and educational outcomes, in more of an environmental and social context, which allowed for possible interventions. One intervention that was particularly successful, funded by a grant from the CDC, was a number of job fairs that we hosted on Meharry Medical College’s campus, which is located in a low-income, predominantly African-American community. The volunteers were from human resources departments from all over the city, and they counseled students from a number of high schools through writing job resumes. The outpouring of community support was really amazing. Our intervention really had impact on reducing problem behaviors and improving students’ grades in the schools that we worked with.

After the CDC grant ended, Dean Stern from the University of Tennessee School of Health Sciences called my wife and I about starting a research center in Memphis focusing on health disparities. He said that Memphis had some really serious problems that need to be addressed, and that the college would love for you to be a part of the efforts to address that. The university as well as the Methodist Health System and the Regional One System all funded the project, which showed a major commitment and desire to address the issue. With a grant from the Environmental Protection Agency, I started to see that health disparities came not only from conventional factors like pollution and poor infrastructure, but also from social, economic and behavioral factors. We call this combination of environmental factors that affect the health of communities the health exposome.

What factors determine and define health disparities and how exposomes contribute to them within a population?

Health exposomes are everything that happens to an individual from conception to death: the water and food that you have access to, the level of stress you experience, whether you come from a low income household, cockroaches, lead-based paint, access to medical professionals, everything. It comes down to four domains: the natural environment, which is the water and land; the built environment, which is housing and transportation; the social environment, which are the social determinants of poverty; and the federal environment, which are the local laws and federal regulations. We have put together a database using these domains and the health outcomes, which we use to identify areas that have high levels of infant mortality or breast cancer or congestive heart failure. From there, we try to find factors that are related to them to determine why certain illnesses happen where they do, and what can be done to prevent those illnesses.

What are some major issues that you found specific to the Memphis community?

Our initial focus was on breast cancer. There was a news article that talked about the disparities of breast cancer in Memphis between African-American and white women: African-American women were dying at twice the rate. There is no difference in incidence, so it wasn’t due to a genetic difference. We reached out to some community partners, including the Congregational Health Network and a non-profit organization support group for African-American women who are survivors of breast cancer. We learned that not only do African-Americans have less access to mammograms, but also they are simply not being referred for mammograms. Mammograms are often referred through primary care providers, which African-American women in Memphis often are not able to visit. More commonly, they only receive health care through urgent care services if they have a pressing health concern. If you ask these women who are breast cancer survivors, why didn’t you get a mammogram earlier, they say well nobody ever told me needed one. So we proposed to use women who are breast cancer survivors to do some outreach and education in different community events and forums.

We are also engaged in research on CANDLE, or Conditions Affecting Neurocognitive Development and Learning in Early Childhood. We wanted to look at the effects of the environment to see if we can identify biological markers in utero and early childhood that might be early indicators of poor neurocognitive development and different diseases early in life. For someone who is exposed to high levels of stress on a continual basis, hormones are released that changes some of the pathways in the fetus. The same thing can happen after the baby is born while the brain is still developing from age one to age three. We are finding that some of these altered pathways are leading to certain social behavior and cognitive development. There is also a merging body of research that links prenatal exposure to stress hormones to asthma and diabetes. On the whole, low income and minority populations are exposed to a greater and more consistent level of stress than other populations, so you see the disparity there. Only ten percent of disparities in chronic disease are related to genetics; the rest is biological, social, and infrastructural environment. We need to understand the impact of the environment and how that works, how the environment gets under the skin.

In the discussion of health disparities, we need to focus on place, rather than race. You have to understand the place, the conditions the people live in, in order to understand why they are experiencing across the board the level of health disparity.

What is the role of local faith-based communities in education and health care?

When you start to identify issues, you have to get involved with those indigenous organizations in those communities. They are the ones that people trust and recognize, and so we work in partnership with them. We can’t as an academic and research institution just go into a community and say, “We know what your problem is and we know the answer.” It’s not going to work. So we have to work with the churches and other small organizations that have a presence and know those communities well.

We have seen education, religion and faith, and money all as ways of attempting to empower a community. How can technology be used as a tool for empowerment?

Empowerment is giving people the sense that they have control over their own destinies. If they have the knowledge and the tools, then they can do something to face their problems. A lot of people believe they can’t do anything. They pull back into the own space and family, they don’t talk to their neighbor, and they don’t work together to achieve a common goal. Empowerment is trying to help people take back their neighborhoods, to take control and have an ability to make changes in their own lives.

Data empowers communities. If they have access to data, that’s information that can help them. On our website – where the “I” and “M” stand for “interactive mapping” – we have data relating to the four domains of exposome: natural, built, social, and policy. People can go on the website and look at all of the social and environmental factors affecting their community.


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