The mental health toll of the Great Migration: a comparison of mental health outcomes among descendants of African American migrators.

INTRODUCTION: Research is beginning to examine the health outcomes of migrators of the Great Migration, a movement of up to eight million African Americans from the South to the North and West during the twentieth century. However, sparse evidence exists studying the health outcomes of the descendants of Great Migration movers. The aim for this study was to compare the lifetime prevalence of mental health disorders by migration status. METHODS: We used a sample of 3183 African American adults from the National Survey of American Life (2001-2003). Using birthplaces of participants and their mothers, we classified adults as (1) Southern stayers, (2) migrators to the South, (3) migrators to the North or (4) Northern stayers. The outcomes were lifetime prevalence of any mental health, mood, anxiety, and substance use disorders. We used weighted log-Poisson regression models and adjusted for demographic characteristics and socioeconomic status. RESULTS: Migrators to the North and Northern stayers had higher risks of any lifetime mental health, mood, anxiety, and substance use disorders compared to Southern stayers in the adjusted models. Migrators to the North and Northern stayers were more likely to report perceived discrimination. CONCLUSION: This study suggests that migrating families to the North may have experienced mental health adversities.

Promoting Health Equity Through Preventing or Mitigating the Effects of Gentrification: A Theoretical and Methodological Guide.

Public health researchers are increasingly questioning the consequences of gentrification for population health and health equity, as witnessed in the rapid increase in public health publications on the health (equity) effects of gentrification. Despite methodological challenges, and mixed results from existing quantitative research, qualitative evidence to date points to the role of gentrification processes in exacerbating health inequities. Here we discuss past methodological and theoretical challenges in integrating the study of gentrification with public health research. We suggest taking an interdisciplinary approach, considering the conceptualization of gentrification in measurement techniques and conceiving this process as a direct exposure or as a part of broader neighborhood changes. Finally, we discuss existingpolicy approaches to mitigating and preventing gentrification and how these could be evaluated for effectiveness and as public health promotion and specifically as interventions to promote health equity.

In Search of the Promised Land: County-Level Disadvantage and Low Birth Weight among Black Mothers of the Great Migration.

The Great Migration was a movement of roughly eight million Black Southerners relocating to the North and West from 1910 to 1980. Despite being one of the most significant mass internal migrations during the twentieth century, little is known about the health outcomes resulting from migration and whether migrators' destination choices were potential mechanisms. This study measured the association between destination county disadvantage and odds of low birth weight during the last decade of the Great Migration. We used the US Census from 1970 as well as the birth records of first-time Black mothers who migrated from the South collected through the National Center of Health Statistics from 1973 to 1980 (n = 154,145). We examined three measures of area-based opportunity: Black male high school graduation rate, Black poverty rate, and racialized economic residential segregation. We used multilevel logistic regression, where mothers were nested within US counties, to quantify the relationship between county disadvantage and low birth weight. After adjusting for individual risk and protective factors for infant health, there was no relationship between county opportunity measures and low birth weight among migrators. Although high socioeconomic opportunity is typically associated with protection of low birth weight, we did not see these outcomes in this study. These results may support that persistent racial discrimination encountered in the North inhibited infant health even as migrators experienced higher economic opportunity relative to the South.

Health Selection Into Eviction: Adverse Birth Outcomes and Children's Risk of Eviction Through Age 5 Years.

Adverse birth outcomes put children at increased risk of poor future health. They also put families under sudden socioeconomic and psychological strain, which has poorly understood consequences. We tested whether infants experiencing an adverse birth outcome-low birthweight or prematurity, as well as lengthy hospital stays-were more likely to be evicted in early childhood, through age 5 years. We analyzed 5,655 observations contributed by 2,115 participants in the Fragile Families and Child Wellbeing Study-a national, randomly sampled cohort of infants born in large US cities between 1998 and 2000-living in rental housing at baseline. We fitted proportional hazards models using piecewise logistic regression, controlling for an array of confounders and applying inverse probability of selection weights. Having been born low birthweight or preterm was associated with a 1.74-fold increase in children's hazard of eviction (95% confidence interval: 1.02, 2.95), and lengthy neonatal hospital stays were independently associated with a relative hazard of 2.50 (95% confidence interval: 1.15, 5.44) compared with uncomplicated births. Given recent findings that unstable housing during pregnancy is associated with adverse birth outcomes, our results suggest eviction and health may be cyclical and co-constitutive. Children experiencing adverse birth outcomes are vulnerable to eviction and require additional supports.

Causal Inference in Studying the Long-Term Health Effects of Disasters: Challenges and Potential Solutions.

Two frequently encountered but underrecognized challenges for causal inference in studying the long-term health effects of disasters among survivors include 1) time-varying effects of disasters on a time-to-event outcome and 2) selection bias due to selective attrition. In this paper, we review approaches for overcoming these challenges and demonstrate application of the approaches to a real-world longitudinal data set of older adults who were directly affected by the 2011 Great East Japan Earthquake and Tsunami (n = 4,857). To illustrate the problem of time-varying effects of disasters, we examined the association between degree of damage due to the tsunami and all-cause mortality. We compared results from Cox regression analysis assuming proportional hazards with those derived using adjusted parametric survival curves allowing for time-varying hazard ratios. To illustrate the problem of selection bias, we examined the association between proximity to the coast (a proxy for housing damage from the tsunami) and depressive symptoms. We corrected for selection bias due to attrition in the 2 postdisaster follow-up surveys (conducted in 2013 and 2016) using multivariable adjustment, inverse probability of censoring weighting, and survivor average causal effect estimation. Our results demonstrate that analytical approaches which ignore time-varying effects on mortality and selection bias due to selective attrition may underestimate the long-term health effects of disasters.

Physical Health Symptoms and Hurricane Katrina: Individual Trajectories of Development and Recovery More Than a Decade After the Storm.

Objectives. To examine how physical health symptoms developed and resolved in response to Hurricane Katrina.Methods. We used data from a 2003 to 2018 study of young, low-income mothers who were living in New Orleans, Louisiana, when Hurricane Katrina struck in 2005 (n = 276). We fit logistic regressions to model the odds of first reporting or "developing" headaches or migraines, back problems, and digestive problems, and of experiencing remission or "recovery" from previously reported symptoms, across surveys.Results. The prevalence of each symptom increased after Hurricane Katrina, but the odds of developing symptoms shortly before versus after the storm were comparable. The number of traumatic experiences endured during Hurricane Katrina increased the odds of developing back and digestive problems just after the hurricane. Headaches or migraines and back problems that developed shortly after Hurricane Katrina were more likely to resolve than those that developed just before the storm.Conclusions. While traumatic experiences endured in disasters such as Hurricane Katrina appear to prompt the development of new physical symptoms, disaster-induced symptoms may be less likely to persist or become chronic than those emerging for other reasons.

Cancer Stage at Diagnosis, Historical Redlining, and Current Neighborhood Characteristics: Breast, Cervical, Lung, and Colorectal Cancers, Massachusetts, 2001-2015.

In the 1930s, maps created by the federal Home Owners' Loan Corporation (HOLC) nationalized residential racial segregation via "redlining," whereby HOLC designated and colored in red areas they deemed to be unsuitable for mortgage lending on account of their Black, foreign-born, or low-income residents. We used the recently digitized HOLC redlining maps for 28 municipalities in Massachusetts to analyze Massachusetts Cancer Registry data for late stage at diagnosis for cervical, breast, lung, and colorectal cancer (2001-2015). Multivariable analyses indicated that, net of age, sex/gender, and race/ethnicity, residing in a previously HOLC-redlined area imposed an elevated risk for late stage at diagnosis, even for residents of census tracts with present-day economic and racial privilege, whereas the best historical HOLC grade was not protective for residents of census tracts without such current privilege. For example, a substantially elevated risk of late stage at diagnosis occurred among men with lung cancer residing in currently privileged areas that had been redlined (risk ratio = 1.17, 95% confidence interval: 1.06, 1.29), whereas such risk was attenuated among men residing in census tracts lacking such current privilege (risk ratio = 1.01, 95% confidence interval: 0.94, 1.08). Research on historical redlining as a structural driver of health inequities is warranted.

Cardiometabolic Profiles and Change in Neighborhood Food and Built Environment Among Older Adults: A Natural Experiment.

BACKGROUND: The association between neighborhood environment and health may be biased due to confounding by residential self-selection. The displacement of disaster victims can act as a natural experiment that exposes residents to neighborhood environments they did not select, allowing for the study of neighborhood effects on health. METHODS: We leveraged data from a cohort of older adults 65 years of age or older living in Iwanuma, Japan, located 80 km west of the 2011 Great East Japan Earthquake and Tsunami. Surveys were conducted 7 months before the disaster, as well as 2.5 and 5.5 years afterward, and linked with medical records. We classified each individual's type of exposure to neighborhood environment based on proximity to local food and recreation destinations and walkability. RESULTS: Fixed-effect models indicated that change in the exposure type from low to high urban density was associated with increased body mass index (0.46 kg/m; 95% confidence interval [CI] = 0.20, 0.73), waist circumference (1.8 cm; 95% CI = 0.56, 3.0), low-density lipoprotein cholesterol (11 mg/dl; 95% CI = 5.0, 17), and decreased high-density lipoprotein cholesterol (-3.1 mg/dl; 95% CI = -5.0, -1.3). We observed similar trends when we analyzed only the individuals who experienced postdisaster relocation to temporary homes. CONCLUSIONS: Increased proximity to food outlets was simultaneously correlated with greater walkability and accessibility to recreational destinations; however, any protective association of physical activity-promoting built environment appeared to be offset by proximity to unhealthy food outlets, especially fast-food restaurants and bars.

Where we eat is who we are: a survey of food-related travel patterns to Singapore's hawker centers, food courts and coffee shops.

BACKGROUND: The development of empirically-grounded policies to change the obesogenic nature of urban environment has been impeded by limited, inconclusive evidence of the link between food environments, dietary behaviors, and health-related outcomes, in part due to inconsistent methods of classifying and analyzing food environments. This study explores how individual and built environment characteristics may be associated with how far and long people travel to food venues,that can serve as a starting point for further policy-oriented research to develop a more nuanced, context-specific delineations of 'food environments' in an urban Asian context. METHODS: Five hundred twenty nine diners in eight different neighborhoods in Singapore were surveyed about how far and long they travelled to their meal venues, and by what mode. We then examined how respondents' food-related travel differed by socioeconomic characteristics, as well as objectively-measured built environment characteristics at travel origin and destination, using linear regression models. RESULTS: Low-income individuals expended more time traveling to meal destinations than high-income individuals, largely because they utilized slower modes like walking rather than driving. Those travelling from areas with high food outlet density travelled shorter distances and times than those from food-sparse areas, while those seeking meals away from their home and work anchor points had lower thresholds for travel. Respondents also travelled longer distances to food-dense locations, compared to food-sparse locations. CONCLUSION: Those seeking to improve food environments of poor individuals should consider studying an intervention radius pegged to typical walking distances, or ways to improve their transport options as a starting point. Policy-focused research on food environments should also be sensitive to locational characteristics, such as food outlet densities and land use.

Gentrification, Neighborhood Change, and Population Health: a Systematic Review.

Despite a proliferation of research on neighborhood effects on health, how neighborhood economic development, in the form of gentrification, affects health and well-being in the USA is poorly understood, and no systematic assessment of the potential health impacts has been conducted. Further, we know little about whether health impacts differ for residents of neighborhoods undergoing gentrification versus urban development, or other forms of neighborhood socioeconomic ascent. We followed current guidelines for systematic reviews and present data on the study characteristics of the 22 empirical articles that met our inclusion criteria and were published on associations between gentrification, and similar but differently termed processes (e.g., urban regeneration, urban development, neighborhood upgrading), and health published between 2000 and 2018. Our results show that impacts on health vary by outcome assessed, exposure measurement, the larger context-specific determinants of neighborhood change, and analysis decisions including which reference and treatment groups to examine. Studies of the health impacts of gentrification, urban development, and urban regeneration describe similar processes, and synthesis and comparison of their results helps bridge differing theoretical approaches to this emerging research. Our article helps to inform the debate on the impacts of gentrification and urban development for health and suggests that these neighborhood change processes likely have both detrimental and beneficial effects on health. Given the influence of place on health and the trend of increasing gentrification and urban development in many American cities, we discuss how future research can approach understanding and researching the impacts of these processes for population health.

A Life-Course Model of Trauma Exposure and Mental Health Among Low-Income Survivors of Hurricane Katrina.

Prior research has provided robust evidence that exposure to potentially traumatic events (PTEs) during a disaster is predictive of adverse postdisaster mental health outcomes, including posttraumatic stress symptoms (PTSS) and nonspecific psychological distress (PD). However, few studies have explored the role of exposure to other PTEs over the life-course in shaping postdisaster mental health. Based on the broader literature on trauma exposure and mental health, we hypothesized a path analytic model linking predisaster PTEs to long-term postdisaster PTSS and PD via predisaster PD, short-term postdisaster symptoms, and disaster-related and postdisaster PTEs. We tested this model using data from the Resilience in Survivors of Katrina study, a longitudinal study of low-income, primarily non-Hispanic Black mothers exposed to Hurricane Katrina and assessed before the disaster and at time points 1, 4, and 12 years thereafter. The models evidenced a good fit with the data, RMSEA < .01-.04, CFIs > .99. In addition, 44.1%-67.4% of the effect of predisaster PTEs on long-term postdisaster symptoms was indirect. Descriptive differences were observed across models that included PTSS versus PD, as well as models that included all pre- and postdisaster PTEs versus only those that involved assaultive violence. The results suggest the importance of incorporating disaster preparedness in clinical work with trauma survivors and the value in attending to other lifetime PTEs when working in postdisaster contexts.

Developing Core Capabilities for Local Health Departments to Engage in Land Use and Transportation Decision Making for Active Transportation.

OBJECTIVE: To develop a core set of capabilities and tasks for local health departments (LHDs) to engage in land use and transportation policy processes that promote active transportation. DESIGN: We conducted a 3-phase modified Delphi study from 2015 to 2017. SETTING: We recruited a multidisciplinary national expert panel for key informant interviews by telephone and completion of a 2-step online validation process. PARTICIPANTS: The panel consisted of 58 individuals with expertise in local transportation and policy processes, as well as experience in cross-sector collaboration with public health. Participants represented the disciplines of land use planning, transportation/public works, public health, municipal administration, and active transportation advocacy at the state and local levels. MAIN OUTCOME MEASURES: Key informant interviews elicited initial capabilities and tasks. An online survey solicited rankings of impact and feasibility for capabilities and ratings of importance for associated tasks. Feasibility rankings were used to categorize capabilities according to required resources. Results were presented via second online survey for final input. RESULTS: Ten capabilities were categorized according to required resources. Fewest resources were as follows: (1) collaborate with public officials; (2) serve on land use or transportation board; and (3) review plans, policies, and projects. Moderate resources were as follows: (4) outreach to the community; (5) educate policy makers; (6) participate in plan and policy development; and (7) participate in project development and design review. Most resources were as follows: (8) participate in data and assessment activities; (9) fund dedicated staffing; and (10) provide funding support. CONCLUSIONS: These actionable capabilities can guide planning efforts for LHDs of all resource levels.

Invited Commentary: Foreclosures and Health in a Neighborhood Context.

Recent systematic reviews link foreclosure to worse health at both the individual and population levels. In this issue of the Journal, Downing et al. (Am J Epidemiol. 2017;185(6):429-435) add to what is known about foreclosure and health by examining annual measures of glycemic control in relation to local foreclosure activity. They provided evidence that between 2007 and 2010, glycemic control was not associated with rates of completed foreclosure among a continuously insured managed-care population of persons with type 2 diabetes living in 9 California counties. In this commentary, I consider 5 possible interpretations of the null results: 1) foreclosures do not affect health in general, 2) glycated hemoglobin is insensitive to local foreclosure activity, 3) the presence of real estate owned foreclosures (rather than the competed foreclosure rate) affects health, 4) an integrated health-care delivery system buffers patients from the effects of the foreclosure crisis, and 5) community conditions and responses to the foreclosure crisis buffer patients from the effects of the foreclosure crisis. I close by arguing that research on the contextual effects of foreclosure on health should continue despite the ongoing recovery of the housing market.

Role of health in predicting moves to poor neighborhoods among Hurricane Katrina survivors.

In contrast to a large literature investigating neighborhood effects on health, few studies have examined health as a determinant of neighborhood attainment. However, the sorting of individuals into neighborhoods by health status is a substantively important process for multiple policy sectors. We use prospectively collected data on 569 poor, predominantly African American Hurricane Katrina survivors to examine the extent to which health problems predicted subsequent neighborhood poverty. Our outcome of interest was participants' 2009-2010 census tract poverty rate. Participants were coded as having a health problem at baseline (2003-2004) if they self-reported a diagnosis of asthma, high blood pressure, diabetes, high cholesterol, heart problems, or any other physical health problems not listed, or complained of back pain, migraines, or digestive problems at baseline. Although health problems were not associated with neighborhood poverty at baseline, those with baseline health problems ended up living in higher poverty areas by 2009-2010. Differences persisted after adjustment for personal characteristics, baseline neighborhood poverty, hurricane exposure, and residence in the New Orleans metropolitan area, with baseline health problems predicting a 3.4 percentage point higher neighborhood poverty rate (95% confidence interval: 1.41, 5.47). Results suggest that better health was protective against later neighborhood deprivation in a highly mobile, socially vulnerable population. Researchers should consider reciprocal associations between health and neighborhoods when estimating and interpreting neighborhood effects on health. Understanding whether and how poor health impedes poverty deconcentration efforts may help inform programs and policies designed to help low-income families move to--and stay in--higher opportunity neighborhoods.

Health Selection into Neighborhoods Among Families in the Moving to Opportunity Program.

Moving to Opportunity for Fair Housing was a randomized experiment that moved very low-income US families from high-poverty neighborhoods to low-poverty neighborhoods starting in the early 1990s. We modeled report of a child's baseline health problem as a predictor of neighborhood outcomes for households randomly assigned to move from high- to low-poverty neighborhoods. We explored associations between baseline health problems and odds of moving with the program upon randomization (1994-1997), neighborhood poverty rate at follow-up (2002), and total time spent in affluent neighborhoods and duration-weighted poverty. Among 1,550 households randomized to low-poverty neighborhoods, a smaller share of households reporting baseline child health problems (P = 0.004) took up the intervention (38%) than those not reporting a health problem (50%). In weighted and covariate-adjusted models, a child health problem predicted nearly 40% lower odds of complying with the experimental condition (odds ratio = 0.62, 95% confidence interval: 0.42, 0.91; P = 0.015). Among compliers, a baseline child health problem predicted 2.5 percentage points' higher neighborhood poverty at take-up (95% confidence interval: 0.90, 4.07; P = 0.002). We conclude that child health problems in a household prior to randomization predicted lower likelihood of using the program voucher to move to a low-poverty neighborhood within the experiment's low-poverty treatment arm and predicted selection into poorer neighborhoods among experimental compliers. Child morbidity may constrain families attempting to improve their life circumstances.

Effects of proximate foreclosed properties on individuals' systolic blood pressure in Massachusetts, 1987 to 2008.

BACKGROUND: No studies have examined the effects of local foreclosure activity on neighbors' blood pressure, despite the fact that spillover effects of nearby foreclosures include many known risk factors for increased blood pressure. We assessed the extent to which living near foreclosed properties is associated with subsequent systolic blood pressure (SBP) measurements. METHODS AND RESULTS: We used 6590 geocoded observations collected from 1740 participants in the Framingham Offspring Cohort across 5 waves (1987-2008) of the Framingham Heart Study to create a longitudinal record of exposure to nearby foreclosure activity. We distinguished between real estate-owned foreclosures, which typically sit vacant, and foreclosures purchased by third-party buyers, which are generally put into productive use. Counts of lender-owned foreclosed properties within 100 m of participants' homes were used to predict measured SBP and odds of being hypertensive. We assessed whether self-reported alcoholic drinks per week and measured body mass index helped to explain the relationship between foreclosure activity and SBP. Each additional real estate-owned foreclosure located within 100 m of a participant's home was associated with an increase in SBP of 1.71 mm Hg (P=0.03; 95% confidence interval, 0.18-3.24) after adjustment for individual- and area-level confounders but not with odds of hypertension. The presence of foreclosures purchased by third-party buyers was not associated with SBP or with hypertension. Body mass index and alcohol consumption attenuated the effect of living near real estate-owned foreclosures on SBP in fully adjusted models. CONCLUSIONS: Real estate-owned foreclosed properties may put nearby neighbors at risk for increased SBP, with higher alcohol consumption and body mass index partially mediating this relationship.

[Inequalities in health: definitions, concepts, and theories]. / Desigualdades en salud: definiciones, conceptos y teorías.

Individuals from different backgrounds, social groups, and countries enjoy different levels of health. This article defines and distinguishes between unavoidable health inequalities and unjust and preventable health inequities. We describe the dimensions along which health inequalities are commonly examined, including across the global population, between countries or states, and within geographies, by socially relevant groupings such as race/ethnicity, gender, education, caste, income, occupation, and more. Different theories attempt to explain group-level differences in health, including psychosocial, material deprivation, health behavior, environmental, and selection explanations. Concepts of relative versus absolute; dose response versus threshold; composition versus context; place versus space; the life course perspective on health; causal pathways to health; conditional health effects; and group-level versus individual differences are vital in understanding health inequalities. We close by reflecting on what conditions make health inequalities unjust, and to consider the merits of policies that prioritize the elimination of health disparities versus those that focus on raising the overall standard of health in a population.

Happily Ever After? Pre-and-Post Disaster Determinants of Happiness Among Survivors of Hurricane Katrina.

This study investigated pre- to post-disaster changes in happiness of 491 women affected by Hurricane Katrina, and identified factors that were associated with the survivors' happiness after the storm. Participants completed surveys approximately 1 year before and 1 and 4 years after the storm. The surveys collected information on the women's happiness, social support, household characteristics, and hurricane exposure. We found that happiness significantly decreased from pre-disaster to 1 year post-disaster but there were no significant differences in happiness between the pre-disaster and 4 years post-disaster assessments. An exception were 38 women who continued to have lower levels of happiness 4 years post-disaster than at pre-disaster. These women were more likely to be living on their own after the storm and reported consistently lower levels of perceived social support from the community both before and after the storm than the other women of the sample. Factors associated with the survivor's happiness after the storm included exposure to hurricane stressors and losing a loved one to the hurricane. These were predictive of lower happiness 1 year post-disaster. Four years after the hurricane only exposure to hurricane stressors was predictive of lower levels of happiness. In contrast, pre-disaster happiness and post-disaster social support were protective against the negative effect of the hurricane on survivors' happiness.

Maternal clinical diagnoses and hospital variation in the risk of cesarean delivery: analyses of a National US Hospital Discharge Database.

BACKGROUND: Cesarean delivery is the most common inpatient surgery in the United States, where 1.3 million cesarean sections occur annually, and rates vary widely by hospital. Identifying sources of variation in cesarean use is crucial to improving the consistency and quality of obstetric care. We used hospital discharge records to examine the extent to which variability in the likelihood of cesarean section across US hospitals was attributable to individual women's clinical diagnoses. METHODS AND FINDINGS: Using data from the 2009 and 2010 Nationwide Inpatient Sample from the Healthcare Cost and Utilization Project--a 20% sample of US hospitals--we analyzed data for 1,475,457 births in 1,373 hospitals. We fitted multilevel logistic regression models (patients nested in hospitals). The outcome was cesarean (versus vaginal) delivery. Covariates included diagnosis of diabetes in pregnancy, hypertension in pregnancy, hemorrhage during pregnancy or placental complications, fetal distress, and fetal disproportion or obstructed labor; maternal age, race/ethnicity, and insurance status; and hospital size and location/teaching status. The cesarean section prevalence was 22.0% (95% confidence interval 22.0% to 22.1%) among women with no prior cesareans. In unadjusted models, the between-hospital variation in the individual risk of primary cesarean section was 0.14 (95% credible interval 0.12 to 0.15). The difference in the probability of having a cesarean delivery between hospitals was 25 percentage points. Hospital variability did not decrease after adjusting for patient diagnoses, socio-demographics, and hospital characteristics (0.16 [95% credible interval 0.14 to 0.18]). A limitation is that these data, while nationally representative, did not contain information on parity or gestational age. CONCLUSIONS: Variability across hospitals in the individual risk of cesarean section is not decreased by accounting for differences in maternal diagnoses. These findings highlight the need for more comprehensive or linked data including parity and gestational age as well as examination of other factors-such as hospital policies, practices, and culture--in determining cesarean section use. Please see later in the article for the Editors' Summary.

Urban sprawl and body mass index among displaced Hurricane Katrina survivors.

OBJECTIVE: Existing research suggests that walkable environments are protective against weight gain, while sprawling neighborhoods may pose health risks. Using prospective data on displaced Hurricane Katrina survivors, we provide the first natural experimental data on sprawl and body mass index (BMI). METHODS: The analysis uses prospectively collected pre- (2003-2005) and post-hurricane (2006-2007) data from the Resilience in Survivors of Katrina (RISK) project on 280 displaced Hurricane Katrina survivors who had little control over their neighborhood placement immediately after the disaster. The county sprawl index, a standardized measure of built environment, was used to predict BMI at follow-up, adjusted for baseline BMI and sprawl; hurricane-related trauma; and demographic and economic characteristics. RESULTS: Respondents from 8 New Orleans-area counties were dispersed to 76 counties post-Katrina. Sprawl increased by an average of 1.5 standard deviations (30 points) on the county sprawl index. Each one point increase in sprawl was associated with approximately .05kg/m(2) higher BMI in unadjusted models (95%CI: .01-.08), and the relationship was not attenuated after covariate adjustment. CONCLUSIONS: We find a robust association between residence in a sprawling county and higher BMI unlikely to be caused by self-selection into neighborhoods, suggesting that the built environment may foster changes in weight.