The Burden of Pedestrian Falls on Streets and Sidewalks in the U.S.

Posted on January 30, 2024 by Built Environment and Health

After doing substantial work documenting the links between greater neighborhood walkability and higher engagement in pedestrian activity and reduced weight gain, in recent years we have launched research projects on pedestrian safety.  In new work just published in the Journal of Urban Health, we show that the population burden of injuries to pedestrians from falls on sidewalks and streets is substantially higher than the burden of injuries to pedestrians from motor vehicles.  This was especially true for pedestrians age 50 years or older.

For the research, data on injurious falls on streets and sidewalks, and pedestrian-motor vehicle collisions, to which Emergency Medical Services responded, along with pedestrian and incident characteristics, were identified in the 2019 National Emergency Medical Services Information System database. In total, 118,520 injurious pedestrian falls and 33,915 pedestrians-motor vehicle collisions were identified, with 89% of the incidents occurring in urban areas. Thirty-two percent of pedestrians struck by motor vehicles were coded as Emergent or Critical by Emergency Medical Services, while 19% of pedestrians injured by falls were similarly coded. However, the number of pedestrians whose acuity was coded as Emergent or Critical was 2.1 times as high for injurious falls as compared with pedestrians-motor vehicle collisions. This ratio was 3.9 for individuals 50 years and older and 6.1 for those 65 years and older.

With the vast majority of injury occurring in urban spaces, the data suggests that urban design, policy, and built environment interventions are important tools for reducing pedestrian fall related morbidity. There has been substantial and appropriate policy attention given to preventing pedestrian injuries from motor vehicles, but disproportionately little to pedestrian falls. We argue that this likely arises from differences in who is responsible for, and who pays for, sidewalk maintenance – individual property owners – and road maintenance – local governments. However, the population burden of injurious pedestrian falls is significantly greater than from pedestrian-motor vehicle injuries and justifies an increased focus on outdoor falls prevention than currently exists across the USA.

Posted in Active Transport, Adults, Pedestrian Injury, Physical Activity, Safety, Transportation, Urban Design, Walkability | Leave a comment

Higher Neighborhood Walkability is Associated with Lower Risk of Obesity Related Cancers

Posted on December 23, 2023 by Built Environment and Health

In collaboration with colleagues at the NYU Women’s Health Study we recently published analyses showing that higher neighborhood walkability is associated with lower risk of obesity related cancers.  Fourteen thousand women were recruited into the study between 1985 and 1991 and followed-up for cancer incidence through 2017.  The participant’s residential histories were compiled throughout this period and the walkability of their Census Tract of residence was measured.  Analyses of the data showed that higher average annual neighborhood walkability during follow-up was associated with lower risk of obesity related cancers. Women with average annual neighborhood walkability score in the top quartile of walkability had a 26% lower risk of obesity-related cancer and a 27% lower risk of postmenopausal breast cancer, compared with women with average annual neighborhood walkability score in the bottom quartile.

One of the long-term goals of the BEH project has been to show how urban design impacts cancer outcomes.  Obesity increases the risk of 13 types of cancer in women, and physical activity lowers the risk for some of these cancers, independent of body size.  Over the years we have shown that higher neighborhood walkability is associated with higher levels of pedestrian activity and overall physical activity and lower body mass index (BMI), lower weight gain and lower obesity risk.  Now, with our collaborators, we have shown in the NYU Women’s Health Study that higher neighborhood walkability is associated with higher levels of walking and lower BMI when the women entered the study and lower obesity related cancer risk over 30 years.     

Posted in Active Transport, Body Mass Index, Cancer Incidence, Obesity, Physical Activity, Urban Design, Walkability | Leave a comment

Eliza Kinsey launches new research on addressing food insecurity among chronic kidney disease patients

Posted on December 23, 2023 by Built Environment and Health

Not quite about the built environment, but BEH member Eliza Kinsey was just awarded a grant from the University of Pennsylvania’s Leonard Davis Institute of Health Economics to test the feasibility, acceptability, and likely effect of a produce prescription intervention on patient-centered outcomes, health behaviors and health outcomes among food insecure adults with stage 3 to 5 chronic kidney disease (CKD).

An estimated 25% of persons with CKD in the U.S. are food insecure, and they are 38% more likely to develop end stage kidney disease than food secure individuals with CKD. Evidence-based treatment to prevent CKD progression includes following a healthy diet rich in fruits and vegetables. However, patients with CKD report difficulty adhering to healthy dietary guidance because of the high cost of healthy foods. With this funding Eliza will launch a randomized controlled trial to examine the feasibility, acceptability, and likely effect of a produce prescription intervention. Participants in the intervention group will receive produce prescription vouchers redeemable at participating retailers for fresh fruits and vegetables. All study participants will be followed for changes to diet quality, food security, quality of life, and clinical outcomes.

Produce prescription programs have shown improved outcomes for people with other chronic conditions, but little research has examined their efficacy or feasibility in populations with kidney disease. The establishment of effective interventions to reduce food insecurity in the CKD population will enable advancements in uptake of evidence-based dietary treatment to prevent disease progression, improvement of health outcomes, and reductions in health disparities.

Eliza is an Assistant Professor of Family Medicine and Community Health at the Perelman School of Medicine and a Senior Fellow at the Leonard Davis Institute of Health Economics.

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Welcoming Dirk Kinsey to the Team

Posted on October 23, 2023 by Built Environment and Health

Dirk Kinsey has joined the BEH team as an Associate Research Scientist. Dirk Kinsey is a health geographer whose research and teaching focus on disparities in health, well-being, and equity. His work applies feminist and critical race epistemologies to understanding urban social and political systems, with a special emphasis on incarceration, health, and wellness. He uses a mixed-methods and cross-epistemological approach to examining inequities in health and wellbeing at the urban and regional scale. Dirk’s dissertation work examines the growth of correctional supervision outside of prison settings and the institutions, policies, and practices that shape and maintain these systems. This research focuses on health inequities experienced by supervised populations and the specific dimensions of supervision that impact individual and community health. He received his PhD in Geography from Temple University in Philadelphia, PA.

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Welcoming Katie Burford to the team

Posted on August 15, 2023 by Built Environment and Health

Katie Burford has joined the BEH team as a Post-Doctoral Fellow in the T32 Program for Advanced Training in Environmental Health and Data Science at the Mailman School of Public Health. Katie is broadly interested in physical activity, pedestrian safety, and urban health inequities. Her research has focused on the measurement of the built and social environment and how it influences children’s physical activity. She wrote her dissertation on measuring traffic-related safety for active commuting to school and received her PhD in Epidemiology from the University of Texas Health Science Center in Austin, Texas.

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A flexible matching strategy for matched nested case-control studies

Posted on August 6, 2023 by Built Environment and Health

Continuing our work on developing epidemiology methods we recently published a paper in Annals of Epidemiology describing a new approach to matching, that we call “flex matching”, in nested case-control studies. We show that flex matching prevents over matching, which is common with traditional approaches to matching, is statistically efficient, and does not increase Type I error.

Traditional Individual matching in case-control studies can improve statistical efficiency over random selection of controls but in practice matched case-control studies are often over matched which produces biased effect estimates and lower statistical efficiency. (The classic paper by Sholom Wacholder on matching is here and an excellent discussion of matching and data analysis by Neil Pearce is here) The issue with traditional matching is that when the matching criteria are complex or restrictive, often controls that meet the matching criteria are not available and the case for which the investigator is seeking a matched control must be dropped from the analysis. When cases are dropped from the analyses bias often occurs and statistical efficiency drops rapidly with each unmatched case that has to be removed from the analytical data set.     

Flex matching uses sequential rounds of matching with loosening of matching criteria in each round. In the first round of matching, controls are matched to cases using the investigator’s preferred matching variables and criteria (e.g., +/- 1 years of age).  In subsequent rounds, controls are sought for cases for which matched controls were not found in the prior rounds using the same matching variables, but with relaxed criteria (e.g., +/- 2 years of age and then +/- 3 years).  After several rounds of increasingly relaxed matching, remaining unmatched cases are randomly assigned a control.  The data are then analyzed using conditional logistic regression with matching variables included as covariates.  We show that this approach reduces bias compared to traditional matching approaches that require the investigator to remove cases from the analytical data set and is more statistically efficient than selecting controls without matching.

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Cumulative experience of neighborhood walkability over a decade and body mass index and waist circumference.

Posted on July 14, 2023 by Built Environment and Health

We just published new work in the American Journal of Epidemiology on the beneficial, cumulative effect of living in neighborhoods with higher walkability on body mass index (BMI) and waist circumference.  In collaboration with the REGARDS team and Drexel’s Urban Health Collaborative, we estimated the walkability of the residential neighborhoods of REGARDS participants, each year, from 2003 to 2016. We found that after ~10 years of follow-up, experiencing higher cumulative neighborhood walkability was associated with significantly lower BMI and smaller waist circumferences for the participants. 

We also investigated whether changes in address were associated with changes in neighborhood walkability, that is: when people move, do they tend to move to more or less walkable neighborhoods?  We found that the first change of residence during follow-up, on average, brought the participants to neighborhoods with higher home values and lower walkability than their originating neighborhoods. Subsequent changes in address brought participants to neighborhoods with similar home values and walkability levels, as their prior neighborhood.

This work adds to the longitudinal evidence that urban design, particularly neighborhood walkability, influences health.

Posted in Active Transport, Adults, Physical Activity, Urban Design, Walkability | Leave a comment

Neighborhood Food Environment and Birth Weight Outcomes in New York City

Posted on June 13, 2023 by Built Environment and Health

Completing our trilogy of papers on neighborhood built environments and pregnancy and birth outcomes, we published a paper in the June issue of JAMA Network Open showing links between neighborhood food environments and birth weight in NYC. Babies born either small- or large-for-gestational age, a measure of birth weight adjusted for length of pregnancy, are at greater risk for long term health complications, but until now little was known about how neighborhood characteristics including walkability and the food environment, may affect birthweight outcomes.

In collaboration with the Bureau of Vital Statistics at the New York City Department of Health and Mental Hygiene we analyzed the records of 106,194 singleton births in NYC in 2015. The prevalence of babies baby born small for gestational age was 13 percent and the percent born large for gestational age was 8.4 percent.  Residing in the most dense healthy retail food environment compared to the lowest was associated with a 11% lower risk of delivering a baby whose weight was low for gestational age.   Conversely, compared to residing in a neighborhood with the lowest density of unhealthy retail food outlets, residing in a neighborhood with the highest density of unhealthy food outlets was associated with a 16 to 18% increase in the risk of a baby being born large for gestational age.

The locations of retail food establishments were identified using the 2014 National Establishment Time Series data set, which provides a census of businesses and institutions in the US. Retail food establishments were a priori grouped into healthy and unhealthy categories based on whether the types of food sold support a healthy weight. For instance, full-service supermarkets and fruit and vegetable markets were classified as healthy, and fast-food outlets, convenience stores, and candy stores as were classified as unhealthy.

The prequel papers in this series reported our findings that higher neighborhood walkability was protective against excess gestational weight gain and against gestational diabetes. The lead author for this paper is Eliza Kinsey who was previosuly a post-doctoral fellow at the Mailman School and is now an Assistant Professor at the Univesity of Pennsylvania.

Posted in Childhood, Food Environment, Healthy Pregnancies, Urban Design | Leave a comment

Causal Inference with Case-Only Studies in Injury Epidemiology Research.

Posted on June 1, 2023 by Built Environment and Health

We recently published a paper in Current Epidemiology Reports describing how the case-only design is commonly misinterpreted in injury epidemiology.  Due to the availability of registries and Emergency Department medical record databases, case-only studies are common in the injury epidemiology literature.  The term “case-only design” covers a variety of epidemiologic designs, with two of the designs being prominent in the injury epidemiology literature; (1) studies to measure exposure effect modification, and (2) studies to uncover etiological heterogeneity.  Although the mechanics of conducting these two study designs are quite similar, the two designs produce results that require completely different interpretations and rely upon different assumptions.  Despite this, in the literature it is common for the results of studies using these two designs to be interpreted in the same way and it is rare that the papers address whether the key assumptions are met. 

We show that the key assumption of case-only designs for exposure effect modification, the more commonly used of the two designs, does not commonly hold for injuries and so results from studies using this design cannot be interpreted. Our paper includes a series of recommendations for the conduct and reporting of case-only designs seeking to test for exposure effect modification.  However, we are quite pessimistic that this design can be effectively used to understand the etiology of injuries or for designing interventions.

Although less commonly used, case-only designs to identify etiological heterogeneity in injury risk are interpretable but only when the case-series is conceptualized as arising from an underlying cohort. However, in the literature the results of studies of this design are often not interpreted correctly.  But we do expect that if these studies are interpreted correctly, they can be used to understand the etiology of injuries or for designing interventions.

Posted in Injury, Methods, Safety, Teaching | Leave a comment

Yoosun Park on “Doin’ The Work” Podcast

Posted on April 7, 2023 by Built Environment and Health

Dr. Yoosun Park was recently interviewed about her paper “Elevate, Humanize, Christianize, Americanize”: Social Work, White Supremacy, and the Americanization Movement, 1880–1930, on the Podcast, Doin’ The Work: Frontline Stories of Social Change. The paper was published in the October 2022 issue of Social Service Review and won the 2023 Frank R. Breul Memorial Prize, which is awarded annually for the article judged by the editor to be the best paper published in Social Service Review in the preceding year.

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