Dr. Zane Hellmann - Best of the Best in Pediatric Surgery 2025

All right, we're going to move on to the next paper and uh this one is Dr. Zane Helman, uh from Yale University School of Medicine in New Haven, Connecticut and he's uh presenting about local infrastructure and economy predicts traffic related fatalities in children. Thank you so much for having me today. My name is Zane Helman and currently, I'm a research resident in the division of pediatric surgery at Yale New Haven Children's Hospital. My hope is to convince you today that improved roadway design for pedestrians leads to safer streets for children both inside and outside motor vehicles. I have nothing to disclose. When thinking about how to mitigate pediatric morbidity from motor vehicle trauma, we have previously advocated for seatbelt safety laws or improved trauma network logistics just to name a few. Although these domains of research and advocacy are vital to improving outcomes for trauma patients, there's one domain of research that is often overlooked that can be summarized in one simple question. What caused the motor vehicle collision in the first place? Think to yourself, would you rather drive or walk on the road on the left or on the right? I may be biased because the street on the right is here in New Haven, but it seems obvious. There are aspects of road of the road on the right including sidewalks and one way traffic that seems to welcome walking and encourage slower driving. I think we all intrinsically have this feeling, but work in our labs sought to prove it empirically. The National Walk Index was formulated by the Environmental Protection Agency using measures of the built environment to determine the likelihood for walking trips in a given area. The walkability index takes into account aspects of intersection density, transit stop proximity and employment and housing mix to create a score for walkability within a community. The fatality analysis reporting system FARS is a nationwide data set maintained by the US Department of Transportation and captures data from all motor vehicle collisions in the United States resulting in a fatality within 30 days. Using both of these data sets, we hypothesized that less walkable areas would correlate with increased motor vehicle child mortality rates. To answer such a complex question though, there are a number of data sets we look to in order to control for the various aspects that might affect motor vehicle fatalities. The walkability index provided the independent variable and the fatality analysis reporting system provided the dependent variable. But there are reasons other than the built environment as to why a child might end up in a fatal motor vehicle collision. So the social vulnerability index was included as it has been shown to correlate with overall trauma fatality rates by county, and the population density was included as to control for urban density and the increased traffic with which it is associated. Primary outcome was mortality, which was first determined by querying the FARS for mortality data set for all fatalities in persons less than 18 years of age between 2017 and 2021, and then dividing the total fatalities within each county by that county's child population as reported in the US Census. All motor vehicle occupants, pedestrians and cyclists were included in the formation of the mortality rates. Counties with fewer than 100,000 children were excluded and univarite and multivarite poisson regression were used to determine relationships between various measures. 158 counties in 40 states were included. Median average child population was 177,000, median walkability score was 11.4. Average mortality rate for included counties was 1.82 deaths per 100,000 children. There was no relationship between county child population and mortality rates. These are heat maps for mortality on the left and uh for mortality on the left and walkability on the right. In the map on the left, areas in red denote counties with high mortality rates. In the map on the right, areas in red represent counties with poor walkability score. As you can see, there is a significant overlap which is further corroborated on univarite analysis. This figure highlights the effect of walkability as on mortality. As you can see, with each decile increase in walkability as shown on the X-axis, there's a relative decrease in mortality as represented on the Y- axis, so that the most walkable counties have the lowest mortality rates. When controlling for both social vulnerability and population density, we found that each decile increase in walkability was associated with a 7% decrease in mortality rate. This effect was largely driven by fatalities affecting children who were occupants of motor vehicles with an 8% decreased observed for each decile increase in walkability. To me this is the crux of the matter. More walkable streets for all people lead to lower mortality rates for children, particularly those in cars. When stratifying counties by vulnerability, walkability had a larger effect on mortality rates in counties with high vulnerability as represented in the graph by the red line. For counties in the top half of vulnerability, there is a 9% decrease in mortality rate for each decile increase in walkability for the most vulnerable counties. Essentially, improving infrastructure can be a way to mitigate trauma disparities that might be due to vulnerability. Finally, counties in the top decile for walkability had half the mortality rate of counties in the bottom decile, even when controlling for county level vulnerability and population density. There are some limitations to this study. First, although the fatality reporting system captures all motor vehicle collisions with at least one fatality, it does not provide insight into the likelihood of non fatal motor vehicle collisions. Second, to improve the stability of analyzed fatality rates, counties were limited to those with at least 100,000 children. This limits the application of these findings to less populous counties in the US and means that further studies are necessary to better characterize these counties, which tend to be less walkable and more rural. In conclusion, increased walkability is associated with decreased pediatric motor vehicle mortality. Historically, physicians have encouraged automakers to improve car safety design, advocated for national highway speed limits or pushed parents to use proper car seats and seat belts for their children. This work highlights a new domain for research and advocacy within the realm of pediatric trauma. In particular, national, state and local policies can be leveraged to improve walkability by altering the built environment and therefore make streets safer for children both inside and outside of cars. This data highlights that such policies might benefit children regardless of social vulnerability in their community. And my hope is that this research lays the groundwork for a new understanding amongst all physicians that local infrastructure policies have measured effects on the well-being of children. Thank you so much for your time. I hope you have a wonderful day. Thank you. Dr. Helman, thanks so much for joining us and great great paper and presentation. Um so you guys used the social vulnerability index as your socio economic. Is there my question is kind of related to that which is that we know SVI includes race as one of the components in the index. Is there a particular reason that you guys chose that over ADI or one of the other indices that might not include race? Um so I think it was twofold. One is um we were looking at this in terms of county level um work and so we wanted to um use an index that was kind of more geared towards the county. The ADI I think is a little bit more local in terms of its measured effects. Um it does the social vulnerability, we kind of wanted to control for a broad number of like aspects that would not just be socio economic. It would also include those other things because those have been shown to affect trauma. Um so I think that was kind of our main reason for including the social vulnerability index over some of the other kind of indexes that have been used and studied within the world of trauma. And I think I think your focus on the built environment is really important and the ways in which we can alter that. Um I wonder if you use a different index whether you might actually see more of a correlation between socio economic deprivation and and the um mortality in part because you're not adjusting for the structural racism that maybe impacts walkability in neighborhoods that are disproportionately um you know, inhabited by people of color. Yeah. I think the other question is like how do you take what you've learned, which is really important and actually translate that into change at a, you know, local level to reduce um the injuries that you're seeing. Yeah, so I think that this was kind of actually the primary study and what I hope to be a number of uh studies coming out um from our our lab, but I think now we're starting to look at more granular um interventions that can be done such as, you know, active school zones or um increased cross crosswalks in given areas. So we're now trying to dive into kind of more local interventions that can be done rather than kind of looking at broader categorizations of walkability um to see if that kind of affects both motor vehicle trauma but also pedestrian trauma. Fantastic. Thank you so much. This is great. I'm going to add 10 seconds. I get all my information from Tok. And uh there's all these videos I'm seeing now where at the street corners they give you big colorful things to walk across and you plant it on the other side of the street corner whether it's like bricks or flags or whatever. So there's low cost ways of doing it. I love the work you're doing. We have those here, Todd. Oh, do we? Yes. Okay. All right, thank you so much. Thank you all. All right.