Exposure to Community Homicide During Pregnancy and Adverse Birth Outcomes: A Within-Community Matched Design

The spatial distribution of heat related hospitalizations and classification of the most dangerous heat events in California at a small-scale level

Many studies have explored the impact of extreme heat on health, but few have investigated localized heat-health outcomes across a wide area. We examined fine-scale variability in vulnerable areas, considering population distribution, local weather, and landscape characteristics. Using 36 different heat event definitions, we identified the most dangerous types of heat events based on minimum, maximum, and diurnal temperatures with varying thresholds and durations. Focusing on California's diverse climate, elevation, and population distribution, we analyzed hospital admissions for various causes of admission (2004-2013). Our matching approach identified vulnerable zip codes, even with small populations, on absolute and relative scales. Bayesian Hierarchical models leveraged spatial correlation. We ranked the 36 heat event types by attributable hospital admissions per zip code and provided code, simulated data, and an interactive web app for reproducibility. Our findings showed high variation in heat-related hospitalizations in coastal cities and substantial heat burdens in the Central Valley. Diurnal heat events had the greatest impact in the Central Valley, while nighttime extreme heat events drove burdens in the southeastern desert. This spatially informed approach guides local policies, prioritizing dangerous heat events to reduce the heat-health burden. The methodology is applicable to other regions, informing early warning systems and characterizing extreme heat impacts.

Reexamining the causes of age patterns in Black-White birth weight disparities: Evidence from U.S. cohorts

Black-White disparities in low birth weight (LBW) rise with maternal age. Why? The "weathering hypothesis" holds that the increasing disparity is due to the accumulation of adverse exposures leading to accelerated aging among Black compared to White mothers. Using US birth certificate data covering millions of births to successive cohorts of US women, this paper finds two sets of results that complicate this theory. Descriptively, I find that Black-White LBW disparities increase with age for some cohorts but not others. More causally, analyses exploiting a plausibly exogenous policy shock show that the effects of reducing adverse exposures were larger for older compared to younger mothers. This evidence points toward an alternative or complementary hypothesis: that LBW risks are more responsive to adverse exposures at older maternal ages than at younger ages. Emphasizing this pathway -- what I call "responsiveness" -- as opposed to accumulation has important implications for both research and policy.

Exposure to Crime and Racial Birth Outcome Disparities

Urban communities in the United States were transformed at the end of the twentieth century by a rapid decline in neighborhood crime and violence. We leverage that sharp decline in violence to estimate the relationship between violent crime rates and racial disparities in birth outcomes. Combining birth certificate data from US counties with the FBI's Uniform Crime Reporting statistics from 1992 to 2002, we show that lower crime rates are associated with substantially smaller Black-White disparities in birth weight, low birth weight, and small for gestational age. These associations are stronger in more segregated counties, suggesting that the impacts of the crime decline may have been concentrated in places with larger disparities in exposure to crime. We also estimate birth outcome disparities under the counterfactual that the crime decline did not occur and show that reductions in crime statistically explain between one-fifth and one-half of the overall reduction in Black-White birth weight, LBW, and SGA disparities that occurred during the 1990s. Drawing on recent literature showing that exposure to violent crime has negative causal effects on birth outcomes, which in turn influence life-course outcomes, we argue that these results suggest that changes in national crime rates have implications for urban health inequality.

Linking Adverse Experiences to Pregnancy and Birth Outcomes: A Life Course Analysis of Racial and Ethnic Disparities Among Low-Income Women

Racial and ethnic disparities in birth outcomes have persisted in the United States for decades, though the causes remain poorly understood. The life course perspective posits that poorer outcomes of Black birthing people stem from heightened exposure to stressors early in life and cumulative exposure to stressors over time. Despite its prominence, this perspective has seldom been investigated empirically. We analyzed longitudinal data gathered from 1319 women in low-income households in Wisconsin who received perinatal home visiting services. Variable- and person-centered analyses were performed to assess whether 15 adverse childhood experiences (ACEs) and 10 adverse adult experiences (AAEs) were associated, alone and in combination, with pregnancy loss, preterm birth, and low birth weight among Hispanic (i.e., Latinx) and non-Hispanic Black and White participants. As expected, there were disparities in preterm birth and low birth weight, and both ACEs and AAEs were linked to poorer pregnancy and birth outcomes. Unexpectedly, bivariate and multivariate analyses showed that the associated effects of ACEs and AAEs were most robust for non-Hispanic White women. A latent class analysis produced four patterns of life course adversity, and multigroup latent class analyses confirmed that, compared to White women, higher-adversity class assignments were associated with less robust effects for Hispanic women, and even less robust effects for Black women. We discuss interpretations of the paradoxical findings, including the possibility that alternative sources of stress such as interpersonal and structural racism may better account for the reproductive disparities that disproportionately affect Black birthing people.

Health of singleton neonates in Switzerland through time and crises: a cross-sectional study at the population level, 2007-2022

BACKGROUND

Being exposed to crises during pregnancy can affect maternal health through stress exposure, which can in return impact neonatal health. We investigated temporal trends in neonatal outcomes in Switzerland between 2007 and 2022 and their variations depending on exposure to the economic crisis of 2008, the flu pandemic of 2009, heatwaves (2015 and 2018) and the COVID-19 pandemic.

METHODS

Using individual cross-sectional data encompassing all births occurring in Switzerland at the monthly level (2007-2022), we analysed changes in birth weight and in the rates of preterm birth (PTB) and stillbirth through time with generalized additive models. We assessed whether the intensity or length of crisis exposure was associated with variations in these outcomes. Furthermore, we explored effects of exposure depending on trimesters of pregnancy.

RESULTS

Over 1.2 million singleton births were included in our analyses. While birth weight and the rate of stillbirth have remained stable since 2007, the rate of PTB has declined by one percentage point. Exposure to the crises led to different results, but effect sizes were overall small. Exposure to COVID-19, irrespective of the pregnancy trimester, was associated with a higher birth weight (+12 grams [95% confidence interval (CI) 5.5 to 17.9 grams]). Being exposed to COVID-19 during the last trimester was associated with an increased risk of stillbirth (odds ratio 1.24 [95%CI 1.02 to 1.50]). Exposure to the 2008 economic crisis during pregnancy was not associated with any changes in neonatal health outcomes, while heatwave effect was difficult to interpret.

CONCLUSION

Overall, maternal and neonatal health demonstrated resilience to the economic crisis and to the COVID-19 pandemic in a high-income country like Switzerland. However, the effect of exposure to the COVID-19 pandemic is dual, and the negative impact of maternal infection on pregnancy is well-documented. Stress exposure and economic constraint may also have had adverse effects among the most vulnerable subgroups of Switzerland. To investigate better the impact of heatwave exposure on neonatal health, weekly or daily-level data is needed, instead of monthly-level data.

Preconception stress exposure from childhood to adolescence and birth outcomes: The impact of stress type, severity and consistency

The negative effects of prenatal stress on offspring health are well established, but there remains little understanding of the influence of stress prior to conception despite known effects on biological systems that are important for a healthy pregnancy. Furthermore, operational definitions of stress vary considerably, and exposure is often characterized via summed, ordinal scales of events. We hypothesized that type, severity, and consistency of preconception stress would be associated with birthweight and gestational age (GA) at birth. Data were drawn from a subsample of participants in the 21-year longitudinal Pittsburgh Girls Study (PGS, N = 2,450) that has followed women annually since childhood. Prior work in the PGS derived three domains of stress exposure between ages 7-17 years related to subsistence (e.g., resource strain, overcrowding), safety (e.g., community violence, inter-adult aggression), and caregiving (e.g., separation, maternal depression). We tested the effects of dimensions of preconception stress on birthweight and GA among offspring of 490 PGS participants who delivered at age 18 or older (n = 490; 76% Black, 20% White, 4% Multiracial). Our hypotheses were partially supported with results varying by stress type and severity and by infant sex. Severity of preconception exposure to subsistence stress was prospectively associated with lower offspring birthweight (B = -146.94, SE = 69.07, 95% CI = -282.66, -11.22). The association between severity of caregiving stress in childhood and adolescence and GA at birth was moderated by infant sex (B = 0.85, SE = .41, 95% CI = 0.04, 1.66), suggesting greater vulnerability to this type of stress for male compared to female infants. Exposure to safety stressors did not predict birth outcomes. Infants of Black compared with White mothers had lower birthweight in all models regardless of preconception stress type, severity or consistency. However, we observed no moderating effects of race on preconception stress-birth outcome associations. Demonstrating specificity of associations between preconception stress exposure and prenatal health has the potential to inform preventive interventions targeting profiles of exposure to optimize birth outcomes.

Exposure to local violent crime and childhood obesity and fitness: Evidence from New York City public school students

This paper estimates the relationship between neighborhood violent crime and child and adolescent weight and fitness. It uses detailed data from the Fitnessgram assessments of public school students in New York City matched to point specific crime data geocoded to students' residential location. Our empirical approach compares the weight and fitness outcomes of students exposed to a violent crime on their residential H-block with those living in the same census tract but not exposed to violent crime in close proximity to their home. We find for adolescent girls, increases in BMI that range from 0.01 to 0.035 standard deviations and an increase in the probability of overweight of 0.5 to 1.7 percentage points. We find little evidence that BMI, obesity, and overweight change as a result of violent crime for adolescent boys, and younger children. Results are not explained by declines in physical fitness.

Declining violence and improving birth outcomes in the US: Evidence from birth certificate data

The decline in crime that occurred in the last decade of the 20th century was one of the most important societal changes in recent US history. In this paper, we leverage the sharp decline in violence that began in the 1990s to estimate the relationship between county-level murder rates and individual-level birth outcomes for Black, Hispanic, and White mothers. Using the FBI's Uniform Crime Reporting data from 1992 to 2002 and individual-level data from more than 30,000,000 US birth certificates, we employ two-way fixed effects models with a rich set of controls to compare births to similar women in the same county who experienced different crime rates during their pregnancies. Elevated murder rates are associated with substantially higher risks of low birth weight for White mothers, low birth weight and small for gestational age among Black mothers, and small for gestational age among Hispanic mothers. Sensitivity analyses show that the existence of confounders that would invalidate these inferences is highly unlikely, suggesting that we have identified causal relationships, even if some uncertainty about the precision of our estimates remains. These findings have potential implications for prenatal and postpartum care, and they add to a growing body of evidence showing that the "Great American Crime Decline" was strongly linked to improved outcomes among groups that experienced the steepest declines in violence.

Effects of maternal exposure to acute stress on birth outcomes: a quasi-experiment study

Numerous studies have shown associations between maternal stress and poor birth outcomes, but evidence is unclear for causal inference. Natural disasters provide an opportunity to study effects of quasi-randomized hardship with an accurate measure of onset and duration. In a population-based quasi-experimental study, we examined the effect of maternal exposure to the January 1998 Québec ice storm on birth outcomes by comparing pregnant mothers who lived in an area hard hit by the ice storm with those in two unaffected regions. In a total of 147,349 singleton births between 1995 and 2001, we used a difference-in-differences method to estimate the effects of the ice storm on gestational age at delivery (GA), preterm birth (PTB), weight-for-gestational-age z-scores (BWZ), large for gestational age (LGA), and small for gestational age (SGA). After adjusting for maternal and sociodemographic characteristics, there were no differences between the exposed and the unexposed mothers for birth outcomes. The estimated differences (exposed vs. unexposed) were 0.01 SDs (95% CI: -0.02, 0.05) for BWZ; 0.10% point (95% CI: -0.95%, 1.16%) for SGA; 0.25% point (95% CI: -0.78%, 1.28%) for LGA; -0.01 week (95% CI: -0.07, 0.05) for GA; and 0.16% point (95% CI: -0.66%, 0.97%) for PTB. Neither trimester-specific nor dose-response associations were observed. Overall, exposure to the 1998 Québec ice storm as a proxy for acute maternal stress in pregnancy was not associated with poor birth outcomes. Our results suggest that acute maternal hardship may not have a substantial effect on adverse birth outcomes.

Occurrence of fatal police violence during pregnancy and hazard of preterm birth in California

BACKGROUND

Exposure to fatal police violence may play a role in population-level inequities in risk for preterm delivery.

OBJECTIVE

To evaluate whether exposure to fatal police violence during pregnancy affects the hazard of preterm delivery and whether associations differ by race/ethnicity and fetal sex.

METHODS

We leveraged temporal variation in incidents of fatal police violence within census tracts to assess whether occurrence of fatal police violence in a person's tract during pregnancy was associated with increased hazard of extremely (20-27 weeks), early (28-31 weeks), moderate (32-33 weeks), and late (32-36 weeks) preterm delivery in California from 2007 to 2015. We used both death records and the Fatal Encounters database to identify incidents of fatal police violence. We estimated hazard ratios (HR) using time-varying Cox proportional hazard models stratified by census tract, controlling for age, race/ethnicity, educational attainment, health insurance type, parity, and the year and season of conception. We further stratified by race/ethnicity and infant sex to evaluate whether there were differential effects by these characteristics.

RESULTS

Exposure to an incident of fatal police violence was associated with a small increase in the hazard of late preterm birth using both the death records (N = 376,029; hazard ratio [HR] 1.05, 95% confidence interval [CI] 1.00, 1.10) and the Fatal Encounters data (N = 938,814; HR 1.03, 95% CI 1.00, 1.06). We also observed an association for moderate preterm birth in the Fatal Encounters data (HR 1.06, 95% CI 0.98, 1.15). We did not observe associations for early or extremely preterm birth in either data source. Larger relative hazards of moderate (HR 1.25, 95% CI 0.93, 1.68) and late preterm delivery (HR 1.18, 95% CI 1.05, 1.33) were observed among Black birth parents with female births in the Fatal Encounters data.

CONCLUSIONS

Preventing police use of lethal force may reduce preterm delivery in communities where such violence occurs.

Associations between neighborhood violence during pregnancy and birth outcomes: evidence from São Paulo's Western Region Birth Cohort

BACKGROUND

Low birth weight and prematurity remain leading causes of infant mortality and morbidity globally. Although extensive literature has highlighted the importance of socioenvironmental characteristics for birth outcomes, the role of indirect violence on health remains fairly understudied.

METHODS

Using geocoded birth records from the ongoing Western Region Birth Cohort (Região Oeste Coorte - ROC-Cohort) of infants born between 2012 and 2014 and geocoded crime reports, we assessed the associations between exposure to violent crimes during pregnancy within a 1-km radius of the mother's residence and low birth weight, preterm delivery, and being born small-for-gestational-age. Violent crime exposure was categorized into quintiles. Multivariate logistic regressions were used to examine the associations between violence exposure and birth outcomes. Models were adjusted for sex, maternal age and education, socioeconomic status, and risk factors such as hypertension, diabetes, smoking, and drinking during pregnancy.

RESULTS

Among the 5268 children included, the average crime exposure during the first two trimesters of pregnancy ranged from 0.44 violent crimes in the least exposed quintile to 12.74 crimes in the most exposed. Compared to children with the lowest violence exposure, children in the highest exposure quintile had higher odds of being born small-for-gestational-age (1.41[1.06-1.89]), preterm (1.35[1.01-1.80]), and low birth weight (1.42[1.03-1.98]). While socioeconomic status and maternal education were positively associated with lower violence exposure, no associations were found between these characteristics and birth outcomes.

CONCLUSIONS

Higher exposure to violent crimes in the close vicinity of pregnant women's residence is associated with substantial increases in the odds of adverse birth outcomes. Policies to improve neighborhood safety can potentially contribute not only to the short-term wellbeing of populations but may also have large social, economic, and health benefits in the long term.

Respiratory hospitalizations and wildfire smoke: a spatiotemporal analysis of an extreme firestorm in San Diego County, California

Wildfire smoke adversely impacts respiratory health as fine particles can penetrate deeply into the lungs. Epidemiological studies of differential impacts typically target population subgroups in terms of vulnerability to wildfire smoke. Such information is useful to customize smoke warnings and mitigation actions for specific groups of individuals. In addition to individual vulnerability, it is also important to assess spatial patterns of health impacts to identify vulnerable communities and tailor public health actions during wildfire smoke events.

METHODS

We assess the spatiotemporal variation in respiratory hospitalizations in San Diego County during a set of major wildfires in 2007, which led to a substantial public health burden. We propose a spatial within-community matched design analysis, adapted to the study of wildfire impacts, coupled with a Bayesian Hierarchical Model, that explicitly considers the spatial variation of respiratory health associated with smoke exposure, compared to reference periods before and after wildfires. We estimate the signal-to-noise ratio to ultimately gauge the precision of the Bayesian model output.

RESULTS

We find the highest excess hospitalizations in areas covered by smoke, mainly ZIP codes contained by and immediately downwind of wildfire perimeters, and that excess hospitalizations tend to follow the distribution of smoke plumes across space (ZIP codes) and time (days).

CONCLUSIONS

Analyzing the spatiotemporal evolution of exposure to wildfire smoke is necessary due to variations in smoke plume extent, particularly in this region where the most damaging wildfires are associated with strong wind conditions.

Relationships between psychosocial stressors among pregnant women in San Francisco: A path analysis

Pregnant women who experience psychosocial stressors, such as stressful life events, poor neighborhood quality, and financial hardship, are at an increased risk for adverse pregnancy outcomes. Yet, few studies have examined associations between multiple stressors from different sources, which may be helpful to better inform causal pathways leading to adverse birth outcomes. Using path analysis, we examined associations between multiple self-reported stressor exposures during and before pregnancy in the Chemicals in Our Bodies-2 study (N = 510), a demographically diverse cohort of pregnant women in San Francisco. We examined associations between eight self-reported exposures to stressors and three responses to stress which were assessed via interview questionnaire at the 2^nd trimester. Stressors included: neighborhood quality, stressful life events, caregiving, discrimination, financial strain, job strain, food insecurity, and unplanned pregnancy. Perceived stress, depression, and perceived community status were included as indicators of self-reported stress response. Our model indicated that women who experienced discrimination and food insecurity had a 3.76 (95% confidence interval [CI] = 1.60, 5.85) and 2.67 (95% CI = 1.31, 4.04) increase in depression scale scores compared to women who did not experience discrimination and food insecurity, respectively. We additionally identified job strain and caregiving for an ill family member as strong predictors of increased depressive symptoms (β = 1.63, 95% CI = 0.29, 3.07; β = 1.48, 95% CI = 0.19, 2.70, respectively). Discrimination, food insecurity, and job strain also influenced depression indirectly through the mediating pathway of increasing perceived stress, although indirect effects were less precise. In our study population, women who experienced discrimination, food insecurity, job strain and caregiving for an ill family member had an increased number of depressive symptoms compared to women who did not experience these stressors. Results from our study highlight the complex relationships between stressors and stress responses and may help to identify possible mediating pathways leading to adverse pregnancy outcomes.