Ethnic density and first episode psychosis in the British Pakistani population: findings from the East Lancashire Early Intervention Service.

BACKGROUND: Elevated risk of psychosis for ethnic minority groups has generally been shown to be mitigated by high ethnic density. However, past survey studies examining UK Pakistani populations have shown an absence of protective ethnic density effects, which is not observed in other South Asian groups. AIMS: To assess the ethnic density effect at a local neighbourhood level, in the UK Pakistani population in East Lancashire. METHOD: Data was collected by the East Lancashire Early Intervention Service, identifying all cases of first episode psychosis (FEP) within their catchment area between 2012 and 2020. Multilevel Poisson regression analyses were used to compare incidence rates between Pakistani and White majority groups, while controlling for age, gender and area-level deprivation. The ethnic density effect was also examined by comparing incidence rates across high and low density areas. RESULTS: A total of 455 cases of FEP (364 White, 91 Pakistani) were identified. The Pakistani group had a higher incidence of FEP compared to the White majority population. A clear effect of ethnic density on rates of FEP was shown, with those in low density areas having higher incidence rates compared to the White majority, whereas incidence rates in high density areas did not significantly differ. Within the Pakistani group, a dose-response effect was also observed, with risk of FEP increasing incrementally as ethnic density decreased. CONCLUSIONS: Higher ethnic density related to lower risk of FEP within the Pakistani population in East Lancashire, highlighting the impact of local social context on psychosis incidence.

Neighborhood social composition and refugee mental health - quasi-experimental evidence of associations from a Danish population register study.

BACKGROUND: Refugees are at an elevated risk of some mental disorders with studies highlighting the contributing role of post-migration factors. Studies of migrant groups show neighborhood social composition, such as ethnic density, to be important. This is the first longitudinal study to examine this question for refugees and uses a novel quasi-experimental design. METHODS: We followed a cohort of 44 033 refugees from being first assigned housing under the Danish dispersal policy, operating from 1986 to 1998, until 2019. This comprised, in effect, a natural experiment whereby the influence of assigned neighborhood could be determined independently of endogenous factors. We examined three aspects of neighborhood social composition: proportion of co-nationals, refugees, and first-generation migrants; and subsequent incidence of different mental disorders. RESULTS: Refugees assigned to neighborhoods with fewer co-nationals (lowest v. highest quartile) were more likely to receive a subsequent diagnosis of non-affective psychosis, incident rate ratio (IRR) 1.25 (95% confidence interval (CI) 1.06-1.48), and post-traumatic stress disorder (PTSD), IRR 1.21 (95% CI I.05-1.39). A comparable but smaller effect was observed for mood disorders but none observed for stress disorders overall. Neighborhood proportion of refugees was less clearly associated with subsequent mental disorders other than non-affective psychosis, IRR 1.24 (95% CI 1.03-1.50). We found no statistically significant associations with proportion of migrants. CONCLUSIONS: For refugees, living in a neighborhood with a lower proportion of co-nationals is related to subsequent increased risk of diagnosed mental disorders particularly non-affective psychosis and PTSD.

Income Loss and Mental Health during the COVID-19 Pandemic in the United States-Investigating the Moderating Role of Race and Metro-Level Co-ethnic Density.

The COVID-19 pandemic has significantly impacted individuals' financial well-being and mental health. This study investigates the relationship between income loss and mental health outcomes during the pandemic, as well as the heterogeneity in this relationship by race/ethnicity and co-ethnic density in the metropolitan area. Using nationally representative Household Pulse Survey data, this study finds that income loss is associated with a heightened risk of depression and anxiety, even after controlling for individual and metropolitan-level characteristics. Co-ethnic density in metropolitan areas worsens the effects of income loss on depression and anxiety for Hispanics and non-Hispanic Blacks while residing in a metropolitan area with more Whites cushions the impact of income loss on depression and anxiety for non-Hispanic Whites. Overall, the study underscores the importance of considering the intersection of race/ethnicity and metropolitan-level co-ethnic density in exploring the influence of economic stressors on mental health.

Ethnic Density as a Key Factor to Narrow Health Disparities: A Case of American Indians and Alaska Natives.

Out of all the racial groups in the United States, people who identify as American Indian and Alaska Native (AI/AN) have disproportionately worse health as a result of living in poverty. The preponderance of research connects poor health with a socioeconomic perspective, which might create prejudice against AI/AN. As already known, AI/AN's high rates of obesity, diabetes, and stroke in comparison with that of other ethnic groups are mainly derived from their impoverished economic conditions that have forced them to consume the food distributed by the U.S. government. When minority health is discussed generally, the ethnic density perspective explains a minority population's positive health despite low socioeconomic status. This perspective helps researchers and practitioners understand the connections of psychological and social factors with physical health and demonstrates positive health effects on minority groups. Despite the high correlation between ethnic density and health having been validated, little to no research has explored AI/AN's health from this perspective. Using 13,064 electronic health records, this research tests the relationship between AI/AN density and health outcomes. This article introduces an innovative analytical strategy (i.e., a data mining technique), which is ideal for discovering frequently appearing health outcomes in a group. The finding reveals positive relationships between health outcomes and AI/AN density.

Lack of fit with the neighbourhood social environment as a risk factor for psychosis - a national cohort study.

BACKGROUND: Many studies report an ethnic density effect whereby psychosis incidence among ethnic minority groups is higher in low co-ethnic density areas. It is unclear whether an equivalent density effect applies with other types of socioeconomic disadvantages. METHODS: We followed a population cohort of 2 million native Danes comprising all those born on 1st January 1965, or later, living in Denmark on their 15th birthday. Socioeconomic disadvantage, based on parents' circumstances at age 15 (low income, manual occupation, single parent and unemployed), was measured alongside neighbourhood prevalence of these indices. RESULTS: Each indicator was associated with a higher incidence of non-affective psychosis which remained the same, or was slightly reduced, if neighbourhood levels of disadvantage were lower. For example, for individuals from a low-income background there was no difference in incidence for those living in areas where a low-income was least common [incidence rate ratio (IRR) 1.01; 95% confidence interval (CI) 0.93-1.10 v. those in the quintile where a low income was most common. Typically, differences associated with area-level disadvantage were the same whether or not cohort members had a disadvantaged background; for instance, for those from a manual occupation background, incidence was lower in the quintile where this was least v. most common (IRR 0.83; 95% CI 0.71-0.97), as it was for those from a non-manual background (IRR 0.77; 95% CI 0.67-0.87). CONCLUSION: We found little evidence for group density effects in contrast to previous ethnic density studies. Further research is needed with equivalent investigations in other countries to see if similar patterns are observed.

Effects of ethnic density on the risk of compulsory psychiatric admission for individuals attending secondary care mental health services: evidence from a large-scale study in England.

BACKGROUND: Black, Asian and minority ethnicity groups may experience better health outcomes when living in areas of high own-group ethnic density - the so-called 'ethnic density' hypothesis. We tested this hypothesis for the treatment outcome of compulsory admission. METHODS: Data from the 2010-2011 Mental Health Minimum Dataset (N = 1 053 617) was linked to the 2011 Census and 2010 Index of Multiple Deprivation. Own-group ethnic density was calculated by dividing the number of residents per ethnic group for each lower layer super output area (LSOA) in the Census by the LSOA total population. Multilevel modelling estimated the effect of own-group ethnic density on the risk of compulsory admission by ethnic group (White British, White other, Black, Asian and mixed), accounting for patient characteristics (age and gender), area-level deprivation and population density. RESULTS: Asian and White British patients experienced a reduced risk of compulsory admission when living in the areas of high own-group ethnic density [odds ratios (OR) 0.97, 95% credible interval (CI) 0.95-0.99 and 0.94, 95% CI 0.93-0.95, respectively], whereas White minority patients were at increased risk when living in neighbourhoods of higher own-group ethnic concentration (OR 1.18, 95% CI 1.11-1.26). Higher levels of own-group ethnic density were associated with an increased risk of compulsory admission for mixed-ethnicity patients, but only when deprivation and population density were excluded from the model. Neighbourhood-level concentration of own-group ethnicity for Black patients did not influence the risk of compulsory admission. CONCLUSIONS: We found only minimal support for the ethnic density hypothesis for the treatment outcome of compulsory admission to under the Mental Health Act.

Receiving hemodialysis in Hispanic ethnic dense communities is associated with better adherence and outcomes among young patients: a retrospective analysis of the Dialysis Outcomes and Practice Patterns Study.

BACKGROUND: Hispanic ethnic density (HED) is a marker of better health outcomes among Hispanic patients with chronic disease. It is unclear whether community HED is associated with mortality risk among ethnically diverse patients receiving maintenance hemodialysis. METHODS: A retrospective analysis of patients in the United States cohort of the Dialysis Outcomes and Practice Patterns Study (DOPPS) database (2011-2015) was conducted (n = 4226). DOPPS data was linked to the American Community Survey database by dialysis facility zip code to obtain % Hispanic residents (HED). One way ANOVA and Kruskal Wallis tests were used to estimate the association between tertiles of HED with individual demographic, clinical and adherence characteristics, and facility and community attributes. Multivariable Cox proportional hazards models were used to estimate the mortality hazard ratio (HR) and 95% CIs by tertile of HED, stratified by age; a sandwich estimator was used to account for facility clustering. RESULTS: Patients dialyzing in facilities located in the highest HED tertile communities were younger (61.4 vs. 64.4 years), more commonly non-White (62.4% vs. 22.1%), had fewer comorbidities, longer dialysis vintage, and were more adherent to dialysis treatment, but had fewer minutes of dialysis prescribed than those in the lowest tertile. Dialyzing in the highest HED tertile was associated with lower hazard of mortality (HR, 0.86; 95% CI, 0.72-1.00), but this association attenuated with the addition of individual race/ethnicity (HR, 0.92; 95% CI, 0.78-1.09). In multivariable age-stratified analyses, those younger than 64 showed a lower hazard for mortality in the highest (vs. lowest) HED tertile (HR, 0.66; 95% CI, 0.49-0.90). Null associations were observed among patients ≥ 64 years. CONCLUSIONS: Treating in communities with greater HED and racial/ethnic integration was associated with lower mortality among younger patients which points to neighborhood context and social cohesion as potential drivers of improved survival outcomes for patients receiving hemodialysis.

Hispanic Ethnic Density May Be Protective for Older Black/African American and Non-Hispanic White Populations for Some Health Conditions: An Exploration of Support and Neighborhood Mechanisms.

BACKGROUND AND PURPOSE: Hispanic ethnic density (HED) is associated with salubrious health outcomes for Hispanics, yet recent research suggests it may also be protective for other groups. The purpose of this study was to test whether HED was protective for other racial-ethnic groups. We tested whether social support or neighborhood social integration mediated the association between high HED and depressive symptoms (CES-D) and physical morbidity 5 years later. Lastly, we tested whether race-ethnicity moderated both main and indirect effects. METHODS: We used Waves 1 (2005-2006), and 2 (2010-2011) from The National Social Life, Health, and Aging Project, a national study of older U.S. adults. Our sample was restricted to Wave 1 adults who returned at Wave 2, did not move from their residence between waves, and self-identified as Hispanic, non-Hispanic White (NHW), or non-Hispanic Black (NHB; n = 1,635). We geo-coded respondents' addresses to a census-tract and overlaid racial-ethnic population data. Moderated-mediation models using multiple imputation (to handle missingness) and bootstrapping were used to estimate indirect effects for all racial-ethnic categories. RESULTS: Depressive symptoms were lower amongst racial-ethnic minorities in ethnically (Hispanic) dense neighborhoods; this effect was not stronger in Hispanics. HED was not associated with physical morbidity. Sensitivity analyses revealed that HED was protective for cardiovascular events in all racial-ethnic groups, but not arthritis, or respiratory disease. Social support and neighborhood social integration were not mediators for the association between HED and outcomes, nor were indirect effects moderated by race-ethnicity. CONCLUSIONS: This study offers some evidence that HED may be protective for some conditions in older adults; however, the phenomena underlying these effects remains a question for future work.

The ethnic density effect in psychosis: a systematic review and multilevel meta-analysis.

BACKGROUND: An 'ethnic' or 'group' density effect in psychosis has been observed, whereby the risk of psychosis in minority group individuals is inversely related to neighbourhood-level proportions of others belonging to the same group. However, there is conflicting evidence over whether this effect differs between minority groups and limited investigation into other moderators. AIMS: To conduct a comprehensive systematic review and meta-analysis of the group density effect in psychosis and examine moderators. METHOD: Four databases were systematically searched. A narrative review was conducted and a three-level meta-analysis was performed. The potential moderating effect of crudely and specifically defined minority groups was assessed. Country, time, area size and whether studies used clinical or non-clinical outcomes were also tested as moderators. RESULTS: Thirty-two studies were included in the narrative review and ten in the meta-analysis. A 10 percentage-point decrease in own-group density was associated with a 20% increase in psychosis risk (OR = 1.20, 95% CI 1.09-1.32, P < 0.001). This was moderated by crudely defined minority groups (F6,68 = 6.86, P < 0.001), with the strongest associations observed in Black populations, followed by a White Other sample. Greater heterogeneity was observed when specific minority groups were assessed (F25,49 = 7.26, P < 0.001). CONCLUSIONS: This is the first review to provide meta-analytic evidence that the risk of psychosis posed by lower own-group density varies across minority groups, with the strongest associations observed in Black individuals. Heterogeneity in effect sizes may reflect distinctive social experiences of specific minority groups. Potential mechanisms are discussed, along with the implications of findings and suggestions for future research.

COVID-19 cases in US counties: roles of racial/ethnic density and residential segregation.

OBJECTIVE: To investigate how racial/ethnic density and residential segregation shape the uneven burden of COVID-19 in US counties and whether (if yes, how) residential segregation moderates the association between racial/ethnic density and infections. DESIGN: We first merge various risk factors from federal agencies (e.g. Census Bureau and Centers for Disease Control and Prevention) with COVID-19 cases as of June 13th in contiguous US counties (N = 3,042). We then apply negative binomial regression to the county-level dataset to test three interrelated research hypotheses and the moderating role of residential segregation is presented with a figure. RESULTS: Several key results are obtained. (1) Counties with high racial/ethnic density of minority groups experience more confirmed cases than those with low levels of density. (2) High levels of residential segregation between whites and non-whites increase the number of COVID-19 infections in a county, net of other risk factors. (3) The relationship between racial/ethnic density and COVID-19 infections is enhanced with the increase in residential segregation between whites and non-whites in a county. CONCLUSIONS: The pre-existing social structure like residential segregation may facilitate the spread of COVID-19 and aggravate racial/ethnic health disparities in infections. Minorities are disproportionately affected by the novel coronavirus and focusing on pre-existing social structures and discrimination in housing market may narrow the uneven burden across racial/ethnic groups.

Associations of Objective and Perceived Neighborhood Ethnic Density on Hazardous Alcohol Use among Latinx Emerging Adults.

Background/Purpose: Emerging adulthood is an important time where substance use often peaks. Neighborhood Latinx ethnic density could be protective against negative health behaviors. Most studies on neighborhood ethnic density have focused on census-level aggregate measures, however perception of the neighborhood ethnic density could differ from objectively measured neighborhood density. This study investigated the effects of neighborhood ethnic density, both perceived ethnic and objectively measured ethnic density, on hazardous alcohol use among Latinx emerging adults in Maricopa County Arizona and Miami-Dade County Florida by gender. Methods: 200 Latinx emerging adults residing in Arizona and Florida completed a cross-sectional survey. Inclusion criteria were being age 18-25, self-identify as Latinx, and currently living in Maricopa County or Miami-Dade County. Data were analyzed using multivariate logistic regression and moderation analyses. Results: There was a statistically significant difference between perceived and objective ethnic density (Kappa = 0.353, p < 0.001). When ethnic density was measured objectively, alcohol use severity was statistically significantly lower for individuals living in highly ethnically dense neighborhoods (OR: 0.34, 95% CI: 0.12, 0.92). However, this association was only found for women in moderation analyses. There was no statistically significant association between perceived ethnic density and alcohol use severity. Conclusion: The present study found a statistically significant decrease in alcohol use severity among Latinx emerging adults who live in highly ethnically dense neighborhoods after adjusting for covariates. Future research should investigate the potential mechanisms in which these neighborhoods protect against alcohol use severity among Latinx emerging adults.

The role of school race/ethnic composition in mental health outcomes: A systematic literature review.

INTRODUCTION: This systematic literature review provides evidence concerning the association of school race/ethnic composition in mental health outcomes among adolescents (ages 11-17 years). A range of mental health outcomes were assessed (e.g., internalizing behaviors, psychotic symptoms) in order to broadly capture the relationship between school context on mental health and psychological wellbeing. METHODS: A search across six databases from 1990 to 2018 resulted in 13 articles from three countries (United States, United Kingdom, and the Netherlands) that met inclusion criteria following a two step review of titles/abstracts and full-text. RESULTS: The existing research on school race/ethnic composition and mental health point to two distinct measures of school composition: density-the proportion of one race/ethnic group enrolled in a school, and diversity-an index capturing the range and size of all race/ethnic groups enrolled in a school. Overall, higher same race/ethnic peer density was associated with better mental health for all adolescents. In contrast, there was no overall strong evidence of mental health advantage in schools with increased diversity. CONCLUSIONS: Theoretical and methodological considerations for future research towards strengthening causal inference, and implications for policies and practices concerning the mental health of adolescent-aged students are discussed.

Acculturation and adjustment of migrants reporting trauma: The contextual effects of perceived ethnic density.

Little is known about the relation between acculturation and socioecological contexts of migrants with a personal trauma history living in the community. This study represents an extension of our previous work and aimed to unpack the perceived neighborhood ethnic density (ED) effect and examine the moderating role of ED on the acculturation-adjustment relation in a community sample of migrants with trauma (N = 99) from developing countries residing in Montreal, Canada. ED was protective against general psychological distress but did not predict posttraumatic symptoms. The ED effect was mediated via degree of acculturation to the French-Canadian mainstream cultural context, rather than heritage acculturation, social support, or discrimination. Moreover, protective effects of French-Canadian mainstream acculturation for depressive symptoms and life satisfaction were found under high but not low ED conditions. Similarities and differences with our previous research as well as theoretical and prevention implications are discussed from a person-environment interaction perspective.

Amygdala reactivity in ethnic minorities and its relationship to the social environment: an fMRI study.

BACKGROUND: Ethnic minority individuals have an increased risk of developing a psychotic disorder, particularly if they live in areas of ethnic segregation, or low own group ethnic density. The neurobiological mechanisms underlying this ethnic minority associated risk are unknown. We used functional MRI to investigate neural responses to faces of different ethnicity, in individuals of black ethnicity, and a control group of white British ethnicity individuals. METHODS: In total 20 individuals of black ethnicity, and 22 individuals of white British ethnicity underwent a 3T MRI scan while viewing faces of black and white ethnicity. Own group ethnic density was calculated from the 2011 census. Neighbourhood segregation was quantified using the Index of Dissimilarity method. RESULTS: At the within-group level, both groups showed greater right amygdala activation to outgroup faces. Between groups, the black ethnicity group showed greater right amygdala activation to white faces, compared to the white ethnicity group. Within the black ethnicity group, individuals living in areas of lower own group ethnic density showed greater right amygdala reactivity to white faces (r = -0.61, p = 0.01). CONCLUSIONS: This is the first time an increased amygdala response to white faces has been demonstrated in individuals of black ethnicity. In the black ethnicity group, correlations were observed between amygdala response and neighbourhood variables associated with increased psychosis risk. These results may have relevance for our understanding of the increased rates of paranoia and psychotic disorders in ethnic minority individuals.

Ethnic density effects for adult mental health: systematic review and meta-analysis of international studies.

BACKGROUND: Despite increased ethnic diversity in more economically developed countries it is unclear whether residential concentration of ethnic minority people (ethnic density) is detrimental or protective for mental health. This is the first systematic review and meta-analysis covering the international literature, assessing ethnic density associations with mental health outcomes. METHODS: We systematically searched Medline, PsychINFO, Sociological Abstracts, Web of Science from inception to 31 March 2016. We obtained additional data from study authors. We conducted random-effects meta-analysis taking into account clustering of estimates within datasets. Meta-regression assessed heterogeneity in studies due to ethnicity, country, generation, and area-level deprivation. Our main exposure was ethnic density, defined as the residential concentration of own racial/ethnic minority group. Outcomes included depression, anxiety and the common mental disorders (CMD), suicide, suicidality, psychotic experiences, and psychosis. RESULTS: We included 41 studies in the review, with meta-analysis of 12 studies. In the meta-analyses, we found a large reduction in relative odds of psychotic experiences [odds ratio (OR) 0.82 (95% confidence interval (CI) 0.76-0.89)] and suicidal ideation [OR 0.88 (95% CI 0.79-0.98)] for each 10 percentage-point increase in own ethnic density. For CMD, depression, and anxiety, associations were indicative of protective effects of own ethnic density; however, results were not statistically significant. Findings from narrative review were consistent with those of the meta-analysis. CONCLUSIONS: The findings support consistent protective ethnic density associations across countries and racial/ethnic minority populations as well as mental health outcomes. This may suggest the importance of the social environment in patterning detrimental mental health outcomes in marginalized and excluded population groups.

The relationship between ethnic composition of the residential environment and self-reported health among Turks and Moroccans in Amsterdam.

BACKGROUND: Previous studies from the US and UK suggest that neighbourhood ethnic composition is associated with health, positive or negative, depending on the health outcome and ethnic group. We examined the association between neighbourhood ethnic composition and self-reported health in these groups in Amsterdam, and we aimed to explore whether there is spatial variation in this association. METHODS: We used micro-scale data to describe the ethnic composition in buffers around the home location of 2701 Turks and 2661 Moroccans. Multilevel regression analysis was used to assess the association between three measures of ethnic composition (% co-ethnics, % other ethnic group, Herfindahl index) and three measures of self-reported health: self-rated health, Physical and Mental Component Score (PCS, MCS). We adjusted for socioeconomic position at individual and area level. We used geographically weighted regression and spatially stratified regression analyses to explore whether associations differed within Amsterdam. RESULTS: Ethnic heterogeneity and own ethnic density were not related to self-rated health for both ethnic groups. Higher density of Turks was associated with better self-rated health among Moroccans at all buffer sizes, with the most significant relations for small buffers. Higher heterogeneity was associated with lower scores on PCS and MCS among Turks (suggesting worse health). We found spatial variation in the association of the density of the other ethnic group with self-rated health of Moroccans and Turks. We found a positive association for both groups, spatially concentrated in the sub-district Geuzenveld. CONCLUSIONS: Our study showed that the association of ethnic composition with self-reported health among Turks and Moroccans in Amsterdam differed between the groups and reveals mainly at small spatial scales. Among both groups, an association of higher density of the other group with better self-rated health was found in a particular part of Amsterdam, which might be explained by the presence of a relatively strong sense of community between the two groups in that area. The study suggests that it is important to pay attention to other-group density, to use area measurements at small spatial scales and to examine the spatial variation in these associations. This may help to identify neighbourhood characteristics contributing to these type of area effects on urban minority health.

Contributions of individual acculturation and neighborhood ethnic density to variations in Hispanic children's respiratory health in a US-Mexican border metropolis.

BACKGROUND: We used an expanded conceptualization of ethnic density at the neighborhood level, tailored to Hispanic majority communities in the USA, and a robust measure of children's acculturation at the individual level, to predict Hispanic children's respiratory health. METHODS: We conducted a cross-sectional survey of 1904 children in 2012 in El Paso, TX, USA. One thousand one hundred and seven Hispanic children nested within 72 census tracts were analyzed. Multilevel logistic regression models with cross-level interactions were used to predict bronchitis, asthma and wheezing during sleep. RESULTS: A neighborhood-level ethnic density factor was a non-significant risk factor while individual-level acculturation was a significant risk factor for the three outcomes. Pest troubles and not having been breastfed as an infant intensified the positive association between ethnic density and bronchitis. Increases in ethnic density intensified the odds of wheezing in sleep if the child was not low birth weight or was not economically deprived. CONCLUSIONS: Results suggest that increasing individual-level acculturation is detrimental for US Hispanic children's respiratory health in this Hispanic majority setting, while high ethnic density neighborhoods are mildly risky and pose more significant threats when other individual-level factors are present.

Neighborhood matters: the impact of Hispanic ethnic density on future depressive symptoms 1-year following an ACS event among Hispanic patients.

The Ethnic Density hypothesis posits that living around others from similar ethnic backgrounds reduces the risk of adverse mental health outcomes such as depression. Contrary to this hypothesis, previous work has shown that Hispanic ethnic density is cross-sectionally associated with increased depressive symptom severity among patients hospitalized with an acute coronary syndrome (ACS; myocardial infarction or unstable angina pectoris). To date, no study has examined the prospective association of Hispanic ethnic density on long-term depressive symptom severity following an acute medical event. We prospectively assessed the impact of Hispanic ethnic density on depressive symptoms, 1-year following an ACS event, among Hispanic adult patients. We tested the non-linear association between ethnic density and depressive symptoms to account for inconsistent findings on the ethnic density hypothesis. At the time of an index ACS event (i.e., baseline, N = 326) and 1-year later (N = 252), Hispanic patients from the Prescription Usage, Lifestyle, and Stress Evaluation prospective cohort study completed the Beck Depression Inventory as a measure of depressive symptom severity. Hispanic ethnic density was defined by the percentage of Hispanic residents within each patient's census tract using data extracted from the American Community Survey Census (2010-2013). Covariates included baseline demographic factors (age, gender, English fluency, education, nativity status), cardiovascular factors (Charlson comorbidity index, left ventricular ejection fraction, Global Registry of Acute Coronary Events 6-month prognostic risk score), and neighborhood factors (residential density, income, and percentage of households receiving public assistance). In an adjusted multivariable linear regression analysis there was a significant curvilinear association between Hispanic ethnic density and depressive symptom severity at 1 year. As Hispanic ethnic density increased from low to moderate density, there was an increase in depressive symptoms, but depressive symptoms slightly declined in census tracts with the highest density of Hispanics. Furthermore, gender significantly moderated the relation between Hispanic ethnic density and 1-year depressive symptom severity, such that Hispanic ethnic density was significantly associated with increased depressive symptom severity for female Hispanic patients with ACS, but not for male Hispanic patients. Previous research suggests that ethnic density may be protective against depression in Hispanic enclaves; however, our findings suggest a non-linear ethnic density effect and an overall more complex association between ethnic density and depression. These data add to a growing body of literature on the effects of sociodemographic and contextual factors on health.

Is ethnic density associated with risk of child pedestrian injury? A comparison of inter-census changes in ethnic populations and injury rates.

OBJECTIVES: Research on inequalities in child pedestrian injury risk has identified some puzzling trends: although, in general, living in more affluent areas protects children from injury, this is not true for those in some minority ethnic groups. This study aimed to identify whether 'group density' effects are associated with injury risk, and whether taking these into account alters the relationship between area deprivation and injury risk. 'Group density' effects exist when ethnic minorities living in an area with a higher proportion of people from a similar ethnic group enjoy better health than those who live in areas with a lower proportion, even though areas with dense minority ethnic populations can be relatively more materially disadvantaged. DESIGN: This study utilised variation in minority ethnic densities in London between two census periods to identify any associations between group density and injury risk. Using police data on road traffic injury and population census data from 2001 to 2011, the numbers of 'White,' 'Asian' and 'Black' child pedestrian injuries in an area were modelled as a function of the percentage of the population in that area that are 'White,' 'Asian' and 'Black,' controlling for socio-economic disadvantage and characteristics of the road environment. RESULTS: There was strong evidence (p < 0.001) of a negative association between 'Black' population density and 'Black' child pedestrian injury risk [incidence (of injury) rate ratios (IRR) 0.575, 95% CI 0.515-0.642]. There was weak evidence (p = 0.083) of a negative association between 'Asian' density and 'Asian' child pedestrian injury risk (IRR 0.901, 95% CI 0.801-1.014) and no evidence (p = 0.412) of an association between 'White' density and 'White' child pedestrian injury risk (IRR 1.075, 95% CI 0.904-1.279). When group density effects are taken into account, area deprivation is associated with injury risk of all ethnic groups. CONCLUSIONS: Group density appears to protect 'Black' children living in London against pedestrian injury risk. These findings suggest that future research should focus on structural properties of societies to explain the relationships between minority ethnicity and risk.

Is ethnic density associated with health in a context of social disadvantage? Findings from the Born in Bradford cohort.

OBJECTIVES: In this study we aimed to test the associations between area-level ethnic density and health for Pakistani and White British residents of Bradford, England. DESIGN: The sample consisted of 8610 mothers and infant taking part in the Born in Bradford cohort. Ethnic density was measured as the percentage of Pakistani, White British or South Asian residents living in a Lower Super Output Area. Health outcomes included birth weight, preterm birth and smoking during pregnancy. Associations between ethnic density and health were tested in multilevel regression models, adjusted for individual covariates and area deprivation. RESULTS: In the Pakistani sample, higher own ethnic density was associated with lower birth weight (ß = -0.82, 95% CI: -1.63, -0.02), and higher South Asian density was associated with a lower probability of smoking during pregnancy (OR = 0.99, 95% CI: 0.98, 1.00). Pakistani women in areas with 50-70% South Asian residents were less likely to smoke than those living in areas with less than 10% South Asian residents (OR = 0.39, 95% CI: 0.16, 0.97). In the White British sample, neither birth weight nor preterm birth was associated with own ethnic density. The probability of smoking during pregnancy was lower in areas with 10-29.99% compared to <10% South Asian density (OR = 0.79, 95% CI: 0.64, 0.98). CONCLUSION: In this sample, ethnic density was associated with lower odds of smoking during pregnancy but not with higher birth weight or lower odds of preterm birth. Possibly, high levels of social disadvantage inhibit positive effects of ethnic density on health.