Risk assessment, explained: Interview with Dr. Travis Bui

In a few weeks, Donald Trump will be inaugurated as the 45th president of the United States. Although science wasn't featured prominently in the lead-up to the election, science inevitably influences our daily lives, in part by informing policy decisions. Last October, Science magazine published six science lessons for the next president, agnostic to exactly who that person would be. Of the issues, including brain health, gene editing, and artificial intelligence, the topic that caught my attention most was risk assessment. It is probably not surprising that this topic most interested me. As a Chancellor's Fellow at the University of California, Davis, I am applying my PhD training in basic biology to a new discipline: the teaching and communication of biotechnology. Despite rigorous, federally-regulated testing and a scientific consensus based on two decades of evidence indicating that genetically engineered (GE) foods pose no greater risk to human health or the environment than conventionally grown foods, a sizable proportion of the public still thinks that GE foods are worse for health than non-GE foods. GE foods remain a contentious subject for which it is clear that scientists and many members of the public evaluate risk differently. Recent evidence suggests that individuals' aversion to GE foods stems in part from a gut instinct that flags them as unnatural, and therefore dangerous. However, as stated in the Science article, "[people] aren't so great at assessing risk" and "gut instinct can lead to poor policy," especially when we let our instincts deny the use of technologies that could be beneficial. Relying on gut instinct alone can lead us to overestimate some risks (such as flying) and underestimate others (such as driving). Scientific risk assessment, on the other hand, uses complex statistical models to make evidence-based determinations of risk. Unfortunately, it is usually performed in ivory towers or behind closed doors, which doesn't aid public understanding of how it works.

I thought it would be helpful to have an expert explain how scientists approach and calculate risk, since this type of evaluation commonly informs policy. Luckily, I have a friend, Dr. Travis Bui, who does risk analysis for a living. I got his take on the subject by conducting an informal interview. Some of Travis' responses have been edited for brevity. Before we start, a requisite disclaimer so that Travis can keep his day job :)

The views and opinions expressed in this interview are those of the interviewee and do not necessarily reflect the official policy or position of any current of former employer.

BA: Hi Travis! You have a PhD in Environmental and Occupational Health from the University of Pittsburgh. What did you study in grad school?

TB: Hi Brittany! My research primarily focused on assessing human health risks from exposure to mycotoxins – toxic substances produced by fungi, which contaminate food around the world. One of the more interesting and complicated projects was assessing climate change impacts on mycotoxin risks in US maize. We found that the mycotoxins that are currently found in the US will decrease, but the levels of aflatoxin and fumonisin will increase. This could prove to cause serious concern for corn growers as aflatoxin is one of the most potent liver carcinogens. My other work focused on assessing the impacts of mycotoxin regulations on human health. The "take home message" from this research was that regulations are often put in place to protect human health, but the positive impact of a regulation in one country could negatively impact another. For example, farmers in less developed regions who attempt to export crops to countries with strict regulatory guidelines will often be forced to export only their highest quality crops while consuming the low quality foods.

BA: What types of risk do you evaluate in your current job?

TB: Currently I am working in the agriculture industry assessing aggregate human health risks to pesticides and genetically modified (GM) foods [Note: the terms genetically engineered (GE) and genetically modified (GM) are used interchangeably throughout this post]. Aggregate risk means that I look at exposure from ALL sources. This includes exposure from food, drinking water, residential exposure, as well as to professional applicators. I take into account all routes of exposure including dermal, inhalation, oral and dietary. The risks are assessed based on a variety of age groups and even gender! The overall process is very in-depth and time consuming. The largest effort goes into the collection of data. Without accurate data, the risk assessments won't be accurate and the risk could be over- or under-estimated.

BA: How would you describe the scientific approach to risk assessment? Think of telling it to your grandma or great-uncle, for example.

TB: The most important thing to remember in risk assessment is that risk is a function of hazard and exposure. Even the most hazardous substance poses no risk if you are never exposed to it and something you are exposed to daily isn't a risk if there is little or no hazard. We'd all agree that a hurricane is very dangerous (hazardous), but if you are living in Iowa, you don't have any exposure and, therefore, have little to no risk from it. Without hazard AND exposure, there is no risk. The scientific approach to risk assessment seeks to incorporate real world (or as close to real world as possible) data for both hazard and exposure. For example, to determine how hazardous a chemical is, a scientist might look in the literature, compare it to a similar chemical, or conduct a study. Exposure may be estimated from a survey, a database, or another study. From here, the data is combined in various statistical and mathematical models to predict risk. These models range in complexity and vary based on the data you have. Assuming you have GOOD data, the more model inputs you have, the more complex the assessment, but the benefit is an increase in accuracy of the assessment. It's a very dynamic process and there isn't a "one-size-fits-all" approach to this science, but the approach is similar in all instances.

BA: Whew! Sounds complicated! So the take-home message is that risk is a function of hazard AND exposure. Can you tell us how the results of risk analyses are interpreted?

TB: Often times, risk assessments may be conducted using a tiered approach. This means that the first pass of a risk assessment could be very simple with limited inputs, but the model is HIGHLY conservative. If the risk is over-estimated and still is acceptable [ie, wouldn't likely harm most people], your work is done! If the assessment isn't acceptable [ie, you get inconclusive results], more data may need to be collected and analyzed in order to more accurately predict the risk. Determining the acceptable level of risk is a whole other issue and varies based on the topic you are working with. In some cases, there is no benefit that will outweigh the risk, but there are many instances when some risk is acceptable because the benefit is worth it. For example, the pharmaceutical industry balances this constantly as you'll see in commercials all the time: benefits of the drug vs. the side effects.

BA: To summarize, it sounds like the process of risk evaluation is iterative and relies on the best available data. Let's switch gears to public perception of risk. Can you name a common misperception regarding risk you have encountered outside of work?

TB: Public misperception of risk is increasingly more common and there are a number of examples that I see on almost a daily basis. One very important thing to keep in mind with regard to risk misperception is social media. Social media is a very powerful tool and is probably one of the biggest culprits in spreading risk misperception. I cannot stress this enough because many of the examples I come across occur on Facebook or Twitter when people begin re-posting information from a celebrity or someone with little or no scientific background on the topic. With that being said, some of the most common encounters I have with risk misperception are the idea that "organic" food is safer than conventionally grown and/or GM-food. There are many other examples like the anti-vaccine movement, but working in agriculture over the past few years, I have become very familiar with the "organic" movement. Fortunately, this has allowed me to spend a great deal of time reviewing literature on both sides of the argument.

BA: How do you typically address misperception of risk regarding GM (or GE) food?

TB: When someone tells me they prefer GMO-free, I always start by asking, "why?" The majority of the time, the response I get is that "because it is safer" and the conversation abruptly ends. In the few instances that the conversation progresses beyond that interaction, I often find that someone read something on the internet or a celebrity tweeted something indicating that organic made them feel better or GM products made them "sick". Ultimately, it is their choice to spend the money, time and effort to eat organic, but I still encourage them to research the topic and understand their decision. The most important thing that I push for as a risk assessor is an educated decision! On the flip side, as a risk assessor, we need to continue to push for better risk communication and have a louder voice. Even a basic understanding of risk-benefits would allow consumers to make more educated decisions. It's important to think back to the risk paradigm – hazard and exposure. Obviously exposure is high since GM proteins are in much of what we eat, but what about the hazard? Fortunately, this topic has been widely studied and thousands of scientific, peer-reviewed literature points out that the toxicity of GM-foods is no more than conventionally produced foods. Ultimately, this means the toxicity component of the risk paradigm is minimal; therefore risk is minimal. The benefits of GM technology far outweigh any possible risks and the peer-reviewed, scientific evidence behind this is increasingly apparent. This argument is much more complex than a short paragraph, but it is important to think about risk as a function of hazard and exposure. As a risk assessor, I hope to encourage people who feel strongly one way or the other to do some research beyond what you read online or see on TV. Consider the source of information, think critically and don't be afraid to ask questions!

BA: I agree that empowering people to critically evaluate the sources of their information is an important step towards addressing risk misperceptions. Okay, last question. Is there a risk-related topic that you think the public should be more aware of? Why?

TB: Many of the risk-related issues the public will face over the next few years are known, but the data needed to properly assess the risk is still being determined. Emerging infectious diseases are always something the public needs to be aware of and the landscape is constantly evolving. A few years ago we dealt with the Ebola virus outbreak and now we are dealing with viruses like Zika and chikungunya. With Ebola, many people survived the virus, which historically had a case fatality rate of nearly 50%. What will the long-term impacts be to survivors? Do they pose future risk as carriers of the virus? Zika is another major concern that the public is aware of, but the actual risk is still undetermined. With the lack of data on both hazard and exposure, this is a topic that requires close monitoring. Obviously, we know the short-term impacts of the Zika virus, but what will the long-term effects be?

A huge thank-you to Dr. Travis Bui for taking the time to participate in this interview. If you'd like to follow up on any of the topics discussed here, please email Brittany at bnanderton@ucdavis.edu

Author: Brittany Anderton