Dustin T. Duncan, ScD is an Assistant Professor in the Department of Population Health at the New York University (NYU) School of Medicine, where he directs NYU’s Spatial Epidemiology Lab. Dr. Duncan is a Social and Spatial Epidemiologist, studying how specific neighborhood characteristics influence population health and health disparities.
I attended one of Dr. Duncan’s presentations on spatial epidemiology a few weeks before conducting this interview. Dr. Duncan proved himself to be a passionate scientist who regularly approaches research on the LGBT community from novel perspectives, especially regarding mobility patterns, neighborhoods, and various health outcomes. Dr. Duncan was in Abu Dhabi teaching a few classes, but he still took the time to answer my questions via Skype. Our conversation, which is left mainly untampered, can be found below:
Introductions, Research Inspirations, and Definitions
Daniel Gore: Hello Dr. Duncan, thanks for agreeing to chat with me today. Can you tell me a little about your academic and professional background, and current pursuits?
DD: My name is Dustin Duncan, and I’m an assistant professor at the NYU School of Medicine. I’m a spatial epidemiologist; I study how neighborhoods influence health behaviors, and health outcomes. Right now, I am studying HIV among black men who have sex with men (MSM). Research wise, I have a number of grants that focus on the influence of HIV among MSM, particularly black MSM, using geospatial technologies like GPS devices. We are hoping to understand where MSM go and link their mobility patterns to health outcomes. This research is important and interesting for lots of reasons, one of which is that in spatial epidemiology, we tend to use crude neighborhood definitions. So we are trying to use innovative and useful ways to understand neighborhoods. I also do a bit of teaching—I teach a class at NYU Abu Dhabi called Connecting Neighborhoods and Health. This year, I’m teaching a class called Social Dimensions of Health at NYU Abu Dhabi as well. I also teach one day seminars for students at the Columbia University School of Public Health called Assessing Neighborhoods in Epidemiology.
DG: What first made you interested in researching spatial epidemiology?
DD: I was a graduate student, and I was working on a project on low-income women in Boston—we were trying to develop a community intervention to increase physical activity. The community intervention included lots of things, including going to neighborhoods and giving community classes to teach physical activity. I remember leaving those classes and going back to my neighborhood, and I simply felt unsafe even though I blended in with the local population. We ended up publishing a paper and found that people who felt unsafe in nighttime, typically women, had significantly less steps than those who felt safe in their neighborhoods. I was truly intrigued by those findings. Then I thought about my life and how I was a poor graduate student. I thought about how I walked to the library a lot, and that I had to walk home at night because public transportation was literally closed. I remember that the only restaurants open and affordable at night were unhealthy food options like pizza. I thought about how context really changes behaviors, including my own behaviors. Consequently, I began thinking we should do a better job of nurturing communities. For example, I never understood why people measure neighborhoods using your home address, zip code, etc. I know my zip code, but I don’t know its physical boundaries. So I felt that GPS would be a useful tool for better studying neighborhoods, especially within the context of MSM, where neighborhood research was not as advanced as it could or should be, and clear HIV rate disparities existed. I thought I could do that type of work, expand the literature in those areas, and try to understand those disparities.
DG: Are a lot of other people conducting this type of research?
DD: I am one of many who are studying neighborhoods and health. I think we all take different approaches to our work, especially in the populations and geographic regions we choose. That being said, I think our group is one of the groups innovating in the area of gay men’s health, particularly using GPS technology to study neighborhoods. But there are other methods that are equally novel and important to studying these concepts.
DG: What gave you the idea of specifically using GPS technology in your research?
DD: So I previously wrote a paper that illustrated spatial misclassification, which is the incorrect measurement of neighborhood exposure based on the definition of neighborhood that is used. In this paper, we compared traditional neighborhood definitions, things like home-based buffers around one’s home. Those are great, but even with buffers, they aren’t totally accurate because we sometimes travel outside of them. Just thinking about in my own life, with my family and friends, how buffers don’t necessarily give an accurate description of where or how someone lives. And that gave me the idea of thinking through GPS.
DG: Going back to terminology, I was interested in discussing some of the phrases that you coined or use in your research. For example, could you define activity space for us?
DD: Activity spaces are basically the location someone visits over a certain period of time. There are many ways to define it. One way is to ask someone what their activity space is. Another way is to ask someone the locations they visit and create the activity space around that. For example, where is your school, work, church, partner’s house, etc? But the method we have used, and which I find to be the most accurate, are GPS devices. What we’ve been doing early on is make sure we define community space in a convincing way, and thinking through how we can find it. We have conducted a number of feasibility studies including one of 75 MSM in NYC using GPS devices to define activity spaces. We are now in the phase of getting more nuanced in our research, like linking different GPS neighborhoods to health outcomes, including HIV risk based on condom-less anal sex, PrEP utilization, and having multiple sexual partners. But to my knowledge, that hasn’t been done before.
DG: And one last term—I was wondering if you could touch on the topic of spatial polygamy?
DD: So the term spatial polygamy originated in geography, spread to sociology, and is now used in public health. It’s the theory/ idea that people experience multiple neighborhoods, and we need to account for these neighborhoods when thinking about one’s mobility patterns, including those related to one’s health. So it really argues against looking at only one neighborhood, but looking at all the neighborhoods one spends time in—their social neighborhoods, their sexual neighborhoods, and their other neighborhoods—we need to consider them all.
DG: Any other important definitions or clarifications?
DD: Just that a GPS is a navigation system that provides location AND time information, just so that’s clear. People have a sense of what a GPS is from their smartphones, but they may not actually know that GPS data is time stamped, meaning you actually know the time and geographic coordinates.
DG: And how accurate are those?
DD: It depends. We haven’t been using GPS technologies on participants’ cellphones. Instead, we have used GPS devices that are dedicated to being carried around and providing geographic coordinates. Those can have a 2-3 meter level of accuracy.
DG: Wow! That’s pretty incredible.
DD: It sure is.
Understanding Neighborhoods through GPS Studies
DG: You previously mentioned this study of 75 participants in NYC. Can you touch on that a little more?
DD: To give some background, we know there are many issues with neighborhood monitoring research, and that people may use definitions of neighborhoods which may not be meaningful. We also know that a lot of research uses neighborhood buffers, which similarly may or may not be meaningful. We have often found that due to spatial polygamy, MSM are likely not found in solely their home neighborhoods as defined by their zip codes or buffers around their homes. So that was some early empirical evidence demonstrating that traditional neighborhood research was not sufficient for MSM, at least in NYC. So we thought that if MSM are spatial polygamists, then it would be cool to use GPS technology to study the activity areas of MSM and their spatial polygamy—and none such studies already existed. We wrote a grant, got funded, and then conducted this study to demonstrate the feasibility of collecting GPS data from a sample of 75 MSM recruiting from an existing cohort study. And essentially, we ended up demonstrating this was feasible, in part using survey items. One of our survey items was “I feel comfortable wearing the GPS wherever I go.” We found that over 90% of respondents agreed or strongly agreed with that statement. We also asked if wearing a “GPS made it more interesting for people to participate in the study,” and 81% of participants agreed or strongly agreed with that statement at baseline. We also demonstrated this research was feasible using travel diaries. In these diaries, we asked participants to charge their GPS devices nightly and to mark the time they wore the GPS devices. We importantly found that 84% of participants wore their GPS devices at least one hour all 7 days.
DG: I read you conducted a similar study in Jackson with 25 black MSM. Did you have similar findings to the NYC study?
DD: We did a multi-site study on black MSM in the south that included 75 participants in Jackson Mississippi, Hattiesburg Mississippi, and New Orleans Louisiana. We generally found that it was feasible for southern, black MSM to engage in our GPS protocols. However, we also found that the level of adherence to our protocols was not as strong as it was in NYC. We’re trying to figure out why that might be, and we’re currently running models to determine this. We think maybe internalized homophobia or the rural nature of Jackson might influence adherence. One reason it could be internalized homophobia is because participants have to wear their GPS devices for our study, and our study center is sometimes known for conducting research on black MSM. You can imagine how someone who is not comfortable with their sexuality might not want to wear their GPS devices.
DG: I recall that in the NYC study, you had 75 participants, 25 who identified as black, 25 as white, and 25 as Hispanic/Latino. Did you notice different adherence rates between the black MSM in the south and those in NYC? Or was the disparity between all southern and all northern participants?
DD: We actually didn’t compare the two studies, and in some ways, they really aren’t comparable. First of all, all these studies are very small—they only have samples of 25 or 75 people. In the NYC study, we found no differences in GPS adherence by race or ethnicity. But the sample of Black MSM in the south, they are a little different from their northern counterparts. They are primarily college students, whereas the participants in NYC were not in college. Colleges in the south are so different from those in NYC. In NYU, the campus is very much part of the city, so people engage with their campus, classes, and the city at the same time. But in more rural areas like Jackson, traditional college campuses are kind of closed-off. So in addition to southern, black MSM having potentially more internalized homophobia, they also may not want to carry their GPS if they are simply going to the cafeteria or some other place on campus.
DG: Aside from internalized homophobia and being in college, are there any other sociocultural factors that might have come into play?
DD: I just think it’s important to remember that the MSM population is not monolithic, and neither is the black MSM population. For example, even from a geographic perspective, we know that HIV prevalence is higher among southern, black MSM populations than those in other locations. Similar concepts apply to cultural factors, even if it’s difficult to empirically point to any. I personally got a different vibe while conducting studies in, let’s say, Chicago vs. the South, but that’s just how I felt.
DG: Based on the success of these initial short-term studies, that there might be feasibility for long term GPS studies in the future? And what would the benefits of such studies be?
DD: Good question. The initial GPS studies collected data from a couple days to a week. Our current studies are now using more comprehensive protocols that include two weeks’ worth of data. We are also, along with Dr. John Schneider, looking at GPS data longitudinally, i.e. we’re collecting data from people at several points in time to get more nuances of their mobility patterns, particularly in populations we wish to study like black MSM. In fact, I tested some of these mobility patterns out on myself. I tracked my mobility patterns with a GPS for two weeks at baseline and did the same thing a month and a half later for another 2 weeks. I saw that my patterns were very different. One was in the summer, and one was in the fall. And this was just two segments in my life—I did nothing special during either of those times. In the summer, I went to different destinations—like beaches, etc. But in the fall, I stayed more in the city, and went mainly to my office and to visit friends and family.
DG: And from a broader perspective, what do you think is the future for such GPS studies? For example, when you sit down and envision what you really want to do with this technology, what do you think of?
DD: I eventually would like to not use a dedicated GPS device and instead use people’s cellphones. We’ve done a little bit of research on that, and it seems feasible. But there are still a few issues with using cellphones. For example, some participants don’t want researchers to know where they go all the time, and feel more comfortable having data recorded on the GPS device. Another goal of mine is spatial-temporal analysis, so thinking about not just space but also time. That hasn’t really been done, especially among black MSM. One final factor would be incorporating GPS and GIS data together, which would allow us to help determine when exposure makes sense and when it doesn’t make sense. For example, if I’m at one location at 12 noon and then the same location at 12 at night, one might be a restaurant where I’m meeting a friend for lunch. But by nighttime, it might have turned into a club. And we know that those changes might influence one’s health. Emerging work should focus on capturing those nuances and analyzing outlets that sell alcohol (like bars and restaurants) and are associated with alcohol use but also HIV risk.
DG: That would be really fascinating.
DD: It is happening.
DG: Wow the future is already here!
Geosocial “Hook Up” Apps, Grindr, and Research
DG: You’ve also done some research on hook-up/dating applications—it seems you conducted several surveys of MSM where you recruited participants through Grindr. Could you tell me about that process?
DD: This work began after we conducted preliminary GPS studies with various populations and discovered Grindr, which is a GPS-based location application for MSM. We thought it would be an important platform to understand gay men’s health and started conducting some studies. We ran these studies in New York, Atlanta, London, Paris, and we’re starting a study this month in Shanghai. The Grindr studies we have conducted so far focus on understanding risk behaviors like condom-less anal sex and attitudes towards PrEP. We are now conducting studies that look at the novel aspects of gay men’s health including sleep, PrEP use, mental health, substance abuse, condom-less anal sex, and neighborhood correlates of health outcomes. One paper we did on Grindr, which was based on our London sample, focused on studying poor sleep health among MSM, which is associated with other poor health outcomes among MSM. No work had been conducted at that point on poor sleep health among MSM, which sounds crazy. We found that a lot of guys didn’t sleep—and that when they did, they had poor sleep. In fact, over 30% had poor sleep quality. In addition, we found that poor sleep quality is associated with poor mental health, condom-less anal sex, and substance abuse.
DG: I was interested by how your lab started to focus on Grindr. On one hand, it seems so intuitive because Grindr is a geolocation-based technology. But it’s quite different from GPS technology—it’s almost like looking at things from the opposite side of the coin, where Grindr does all the GPS tracking and you simply reach out and conduct surveys.
DD: Well, a student of mine approached me and wanted to do some Grindr work. We thought it would be a unique way to understand gay men’s health—that’s why we did it. There are tons of ways to sample people and understand associations. It really depends on your interests, resources, etc. However, we also wanted to sample Grindr users because generally people think, although we aren’t sure, that it is a high risk sample of MSM. Emerging work shows that guys who use Grindr are generally like your average MSM, but there might be some increased risk for HIV due to a potential increase in sexual partners. And from a theoretical perspective, it kind of makes sense. This application is predominantly a “hook up” application, which can lead to sex, including condom-less sex. Ultimately, there are a wide variety of ways in which you can sample populations, including gay men, though they vary in helpfulness depending on the research questions. Right now, our group is pursuing projects that sample LGBT-identified guys in order to explore how neighborhoods influence gay men’s health. So not just looking at mobility and sampling guys on Grindr, but other ways as well. And I’ll just say that broadly speaking, we are dedicated to understanding novel aspects of context including neighborhoods and health outcomes overall, HIV being one of them.
DG: In the future, are you considering combining some of these technologies such as GPS and geolocation apps, and creating some type of map that demonstrates elevated risk or other health outcomes?
DD: Yes, I am. And our group has thought about the importance of partnering not just with communities but also companies to understand health. So Grindr could be one of those future partners—I’m not sure entirely what that would take, but it’s possible. This might even take the form of helping applications or companies improve their algorithms if their services somehow impact health.
DG: In addition to research, do you think that such technologies could be used to implement HIV /STI prevention interventions?
DD: Absolutely! There is so much we could do there. And I would say our next generation of work is about pushing the realm of interventions, so we’re not just going to focus on observational epidemiological investigations. We have done a lot of work on Grindr about trying to understand geosocial network applications and health risk, and just gauging gay men’s health problems. And I’ll say that it’s possible, for example, to send Grindr users, who you know are at high risk for contracting HIV based on their neighborhood or otherwise, to send them a message to get tested. I mean, the sky is the limit there. We are thinking about how to plan, evaluate, and implement interventions that focus on geography and take them very seriously, given that our work has shown that geography matters.
Summary of Research Goals
DG: Now that you answered my questions, I was wondering if you had any final comments before wrapping up this interview?
DD: Just that our group is really interested in studying how and why neighborhoods influence health, especially as it relates to health disparities. The vast majority of our work currently focuses on men who have sex with men, especially black MSM. And we’re heavily interested in using these technologies to help understand the nuances. All of our projects are interesting and important both substantively and technologically speaking. In my field, we tend to focus solely on neighborhoods, but we don’t think about other things that matter like networks, which influence how we move through our neighborhoods. So our emerging studies with John and colleagues at UC don’t just focus on neighborhoods, but also on the dynamics between neighborhoods and networks; we think there can be two strong social contextual variables that affect one’s health broadly speaking. I think that’s a good ending and summary to the work we’re doing, including with John. Ultimately, we’re not only doing work that we care about, but that could potentially save people’s lives, all through a novel lens.
DG: Yes, I would agree with that.
DD: Well, how was I Daniel? Was I ok?
DG: (Laughs) you did great.