Are neighborhood-level characteristics associated with indoor allergens in the household?

In-home environmental exposures predicted from geospatial characteristics of the built environment and electronic health records of children with asthma

PURPOSE

Children may be exposed to numerous in-home environmental exposures (IHEE) that trigger asthma exacerbations. Spatially linking social and environmental exposures to electronic health records (EHR) can aid exposure assessment, epidemiology, and clinical treatment, but EHR data on exposures are missing for many children with asthma. To address the issue, we predicted presence of indoor asthma trigger allergens, and estimated effects of their key geospatial predictors.

METHODS

Our study samples were comprised of children with asthma who provided self-reported IHEE data in EHR at a safety-net hospital in New England during 2004-2015. We used an ensemble machine learning algorithm and 86 multilevel features (e.g., individual, housing, neighborhood) to predict presence of cockroaches, rodents (mice or rats), mold, and bedroom carpeting/rugs in homes. We reduced dimensionality via elastic net regression and estimated effects by the G-computation causal inference method.

RESULTS

Our models reasonably predicted presence of cockroaches (area under receiver operating curves [AUC] = 0.65), rodents (AUC = 0.64), and bedroom carpeting/rugs (AUC = 0.64), but not mold (AUC = 0.54). In models adjusted for confounders, higher average household sizes in census tracts were associated with more reports of pests (cockroaches and rodents). Tax-exempt parcels were associated with more reports of cockroaches in homes. Living in a White-segregated neighborhood was linked with lower reported rodent presence, and mixed residential/commercial housing and newer buildings were associated with more reports of bedroom carpeting/rugs in bedrooms.

CONCLUSIONS

We innovatively applied a machine learning and causal inference mixture methodology to detail IHEE among children with asthma using EHR and geospatial data, which could have wide applicability and utility.

Material Hardship and Indoor Allergen Exposure among Low-Income, Urban, Minority Children with Persistent Asthma

Traditional measures of socioeconomic status (SES) are associated with asthma morbidity, but their specific contributions are unclear. Increased exposure to indoor allergens among low SES children is an important consideration. Material hardship, a concept describing poor access to basic goods and services, may explain the relationship between low SES and indoor allergen exposure, and thereby, the increased risk of asthma morbidity. We sought to (i) describe the specific hardships experienced by low-Income, urban, minority children with asthma and indoor allergen sensitization and (ii) determine if material hardship is associated with indoor allergen exposure in this population. We conducted a cross-sectional analysis of children undergoing the baseline assessment for a clinical trial of home environmental modification. Participants were scored in five domains of material hardship. Domain scores were assigned based on caregiver responses to a questionnaire and were summed to generate a total material hardship score. Linear regression was used to examine the relationship between material hardship scores and bedroom floor concentrations of five common indoor allergens. Participants experienced high levels of material hardship in each of the five domains, with 33% not having access to a car, 35% not being able to pay utility bills, and 28% not being able to pay rent in the past year. Each one-point increase in material hardship was associated with an increase in cockroach allergen of 16.2% (95% CI 9.4%, 24.6%) and an increase in mouse allergen of 9.4% (95% CI 1.0%, 18.5%). After adjusting for traditional measures of SES, including household income, health insurance type, caregiver education, and caregiver employment status, the association between material hardship and cockroach allergen, but not mouse allergen, remained. These data suggest that a significant proportion of families of low-income, minority children with asthma may experience material hardship, and that they may be at greater risk of cockroach allergen exposure than their peers with similar income, but without material hardship.

Area Deprivation as a Risk Factor for Methicillin-resistant Staphylococcus aureus Infection in Pediatric Cystic Fibrosis

BACKGROUND

In US cystic fibrosis (CF) patients, methicillin-resistant Staphylococcus aureus (MRSA) rates have tripled in the past 2 decades. Known clinical risk factors include exposure to a healthcare setting, Pseudomonas aeruginosa and CF-related diabetes. Area-level socio-environmental exposures have not been evaluated. We explored the association of area-level deprivation with MRSA prevalence in a pediatric CF Center in the Southeastern United States.

METHODS

Patients' residential addresses were geocoded and linked to a composite Area Deprivation Index and Rural-Urban Commuting Area scores. The association of MRSA with Area Deprivation Index and Rural-Urban Commuting Area scores was evaluated using logistic regression with robust standard errors adjusted for sociodemographic covariates (age, sex, race, mother's and father's education and household income), clinical risk factors (P. aeruginosa, CF-related diabetes, hospitalizations and number of clinic visits) and clustering.

RESULTS

The study included all pediatric patients (N = 231; mean age 12) at a single CF Center. MRSA was present in 44% of subjects. Higher area-level deprivation was correlated with rural residence, lack of parental college education and lower household income (P < 0.001 for each). In a multiple regression model fully adjusted for patient-level sociodemographic covariates, clinical risk factors and clustering, neighborhood deprivation was associated with more than 2-fold increase in the odds of having MRSA [OR 2.26 (1.14-4.45), P < 0.05].

CONCLUSIONS

Neighborhood deprivation is a risk factor for MRSA in pediatric CF, doubling the odds of infection. Community-level socioeconomic risk factors should be considered when developing prevention strategies and treatment plans for MRSA infection in pediatric patients with CF.

Pervasive Income-Based Disparities In Inpatient Bed-Day Rates Across Conditions And Subspecialties

Building a culture of health in hospitals means more than participating in community partnerships. It also requires an enhanced capacity to recognize and respond to disparities in utilization patterns across populations. We identified all pediatric hospitalizations at Cincinnati Children's Hospital Medical Center, in the period 2011-16. Each hospitalized child's address was geocoded, allowing us to calculate inpatient bed-day rates for each census tract in Hamilton County, Ohio, across all causes and for specific conditions and pediatric subspecialties. We then divided the census tracts into quintiles based on their underlying rates of child poverty and calculated bed-day rates per quintile. Poorer communities disproportionately bore the burden of pediatric hospital days. If children from all of the county's census tracts spent the same amount of time in the hospital each year as those from the most affluent tracts, approximately twenty-two child-years of hospitalization time would be prevented. Of particular note were "hot spots" in high-poverty census tracts neighboring the hospital, where bed-day rates were more than double the county average. Hospitals that address disparities would benefit from a more comprehensive understanding of the culture of health-a culture that is more cohesive inside the hospital and builds bridges into the community.

Neighborhoods, Schools, and Academic Achievement: A Formal Mediation Analysis of Contextual Effects on Reading and Mathematics Abilities

Although evidence indicates that neighborhoods affect educational outcomes, relatively little research has explored the mechanisms thought to mediate these effects. This study investigates whether school poverty mediates the effect of neighborhood context on academic achievement. Specifically, it uses longitudinal data from the Panel Study of Income Dynamics, counterfactual methods, and a value-added modeling strategy to estimate the total, natural direct, and natural indirect effects of exposure to an advantaged rather than disadvantaged neighborhood on reading and mathematics abilities during childhood and adolescence. Contrary to expectations, results indicate that school poverty is not a significant mediator of neighborhood effects during either developmental period. Although moving from a disadvantaged neighborhood to an advantaged neighborhood is estimated to substantially reduce subsequent exposure to school poverty and improve academic achievement, school poverty does not play an important mediating role because even the large differences in school composition linked to differences in neighborhood context appear to have no appreciable effect on achievement. An extensive battery of sensitivity analyses indicates that these results are highly robust to unobserved confounding, alternative model specifications, alternative measures of school context, and measurement error, which suggests that neighborhood effects on academic achievement are largely due to mediating factors unrelated to school poverty.

Bedroom Allergen Exposure Beyond House Dust Mites

PURPOSE OF REVIEW

The review provides insight into recent findings on bedroom allergen exposures, primarily focusing on pet, pest, and fungal exposures.

RECENT FINDINGS

Large-scale studies and improved exposure assessment technologies, including measurement of airborne allergens and of multiple allergens simultaneously, have extended our understanding of indoor allergen exposures and their impact on allergic disease. Practical, streamlined methods for exposure reduction have shown promise in some settings, and potential protective effects of early-life exposures have been further elucidated through the investigation of specific bacterial taxa. Advances in molecular allergology have yielded novel data on sensitization profiles and cross-reactivity. The role of indoor allergen exposures in allergic disease is complex and remains incompletely understood. Advancing our knowledge of various co-exposures, including the environmental and host microbiome, that interact with allergens in early life will be crucial for the development of efficacious interventions to reduce the substantial economic and social burden of allergic diseases including asthma.

Mapping Neighborhood Health Geomarkers To Clinical Care Decisions To Promote Equity In Child Health

Health disparities, which can be understood as disadvantages in health associated with one's social, racial, economic, or physical environment, originate in childhood and persist across an individual's life course. One's neighborhood may drive or influence these disparities. Information on neighborhoods that can characterize their risks-what we call place-based risks-is rarely used in patient care. Community-level data, however, could inform and personalize interventions such as arranging for mold removal from the home of a person with asthma from the moment that person's address is recorded at the site of care. Efficient risk identification could lead to the tailoring of recommendations and targeting of resources, to improve care experiences and clinical outcomes while reducing disparities and costs. In this article we highlight how data on place-based social determinants of health from national and local sources could be incorporated more directly into patient-centered care, adding precision to risk assessment and mitigation. We also discuss how this information could stimulate cross-sector interventions that promote health equity: the attainment of the highest level of health for neighborhoods, patient panels, and individuals. Finally, we draw attention to research questions that focus on the role of geographical place at the bedside.

Racial Differences in Food Allergy Phenotype and Health Care Utilization among US Children

BACKGROUND

Food allergy (FA) is a prevalent condition in the United States, but little is known about its phenotypes in racial minority groups.

OBJECTIVE

The objective of this study was to characterize disease phenotypes and disparities in health care utilization among African American (AA), Hispanic, and white children with FA.

METHODS

We conducted a large, 2-center, retrospective cohort study of children aged 0-17 years with FA seen in allergy/immunology clinics at 2 urban tertiary care centers in the United States. We used multiple logistic regression analyses adjusted for age, gender, and insurance.

RESULTS

The cohort of 817 children was composed of 35% AA, 12% Hispanic, and 53% non-Hispanic white. Compared with non-Hispanic white children, AA children had significantly higher odds of having asthma and eczema (P < .01), and significantly higher odds of allergy to wheat, soy, corn, fish, and shellfish (P < .01). Compared with non-Hispanic white children, Hispanic children had significantly higher odds of allergy to corn, fish, and shellfish (P < .01), and higher odds of eczema (P < .01), but a similar rate of asthma (P = .44). In this cohort, 55%, 18%, and 11% of AA, Hispanic, and white children were covered by Medicaid, respectively (P < .00001). Compared with whites, AA and Hispanic children had a shorter duration of follow-up for FA with an allergy specialist and higher rates of FA-related anaphylaxis and emergency department visits (P < .01).

CONCLUSIONS

FA phenotypes and health care utilization differ among children of different racial and/or ethnic backgrounds in the United States that put AA and Hispanic children at higher risks of adverse outcome than white children. These differences include coexistent atopic conditions, less well recognized food allergens, and higher rates of anaphylaxis.

Housing code violation density associated with emergency department and hospital use by children with asthma

Local agencies that enforce housing policies can partner with the health care system to target pediatric asthma care. These agencies retain data that can be used to pinpoint potential clusters of high asthma morbidity. We sought to assess whether the density of housing code violations in census tracts-the in-tract asthma-relevant violations (such as the presence of mold or cockroaches) divided by the number of housing units-was associated with population-level asthma morbidity and could be used to predict a hospitalized patient's risk of subsequent morbidity. We found that increased density in housing code violations was associated with population-level morbidity independent of poverty, and that the density explained 22 percent of the variation in rates of asthma-related emergency department visits and hospitalizations. Children who had been hospitalized for asthma had 1.84 greater odds of a revisit to the emergency department or a rehospitalization within twelve months if they lived in the highest quartile of housing code violation tracts, compared to those living in the lowest quartile. Integrating housing and health data could highlight at-risk areas and patients for targeted interventions.

Mapping the urban asthma experience: Using qualitative GIS to understand contextual factors affecting asthma control

Asthma is complex and connected to a number of factors including access to healthcare, crime and violence, and environmental triggers. A mixed method approach was used to examine the experiences of urban people with asthma in controlling their asthma symptoms. The study started with an initial phase of qualitative interviews in West Philadelphia, a primarily poor African American community. Data from qualitative, semi-structured interviews indicated that stress, environmental irritants, and environmental allergens were the most salient triggers of asthma. Based on the interviews, the team identified six neighborhood factors to map including crime, housing vacancy, illegal dumping, tree canopy and parks. These map layers were combined into a final composite map. These combined methodologies contextualized respondents' perceptions in the framework of the actual community and built environment which tells a more complete story about their experience with asthma.

Inner city asthma

The inner city has long been recognized as an area of high asthma morbidity and mortality. A wide range of factors interact to create this environment. These factors include well-recognized asthma risk factors that are not specific to the inner city, the structure and delivery of health care, the location and function of the urban environment, and social inequities. In this article, these facets are reviewed, and successful and unsuccessful interventions are discussed, to understand what is needed to solve this problem.

Associations of neighborhood concentrated poverty, neighborhood racial/ethnic composition, and indoor allergen exposures: a cross-sectional analysis of los angeles households, 2006-2008

Although racial/ethnic, socioeconomic, and neighborhood factors have been linked to asthma, and the association between indoor allergens and asthma is well documented, few studies have examined the relationship between these factors and indoor allergens. We examined the frequency of reported indoor allergens and differences by racial/ethnic, socioeconomic, and neighborhood characteristics among a diverse sample of Los Angeles households. Multilevel logistic regression models were used to analyze the data from 723 households from wave 2 of the Los Angeles Family and Neighborhood Survey. The reported presence of rats, mice, cockroaches, mold, pets, and tobacco smoke were the primary outcomes of interest. Hispanic and Asian households had a nearly threefold increase in the odds of reporting cockroaches compared to non-Hispanic Whites (OR, 2.85; 95 % CI 1.38-5.88 and OR, 2.62; 95 % CI 1.02-6.73, respectively) even after adjusting for socioeconomic factors. Primary caregivers who had obtained a high school degree were significantly less likely to report the presence of mice and cockroaches compared to primary caregivers with less than a high school degree (OR, 0.19; 95 % CI 0.08-0.46 and OR, 0.39; 95 % CI 0.23-0.68, respectively). Primary caregivers with more than a high school degree were also less likely to report the presence of rats, mice, and cockroaches within their households, compared to those with less than a high school degree. Compared to renters, home owners were less likely to report the presence of mice, cockroaches, and mold within their households. At the neighborhood level, households located within neighborhoods of high concentrated poverty (where the average poverty rate is at least 50 %) were more likely to report the presence of mice and cockroaches compared to households in low concentrated poverty neighborhoods (average poverty rate is 10 % or less), after adjusting for individual race/ethnicity and socioeconomic characteristics. Our study found evidence in support of neighborhood-level racial/ethnic and socioeconomic influences on indoor allergen exposure, above and beyond individual factors. Future studies should continue to explore individual and neighborhood-level racial/ethnic and socioeconomic differences in household allergen exposures across diverse contexts.

Inequalities in neighborhood child asthma admission rates and underlying community characteristics in one US county

OBJECTIVES

To characterize variation and inequalities in neighborhood child asthma admission rates and to identify associated community factors within one US county.

STUDY DESIGN

This population-based prospective, observational cohort study consisted of 862 sequential child asthma admissions among 167 653 eligible children ages 1-16 years in Hamilton County, Ohio. Admissions occurred at a tertiary-care pediatric hospital and accounted for nearly 95% of in-county asthma admissions. Neighborhood admission rates were assessed by geocoding addresses to city- and county-defined neighborhoods. The 2010 US Census provided denominator data. Neighborhood admission distribution inequality was assessed by the use of Gini and Robin Hood indices. Associations between neighborhood rates and socioeconomic and environmental factors were assessed using ANOVA and linear regression.

RESULTS

The county admission rate was 5.1 per 1000 children. Neighborhood rates varied significantly by quintile: 17.6, 7.7, 4.9, 2.2, and 0.2 admissions per 1000 children (P < .0001). Fifteen neighborhoods containing 8% of the population had zero admissions. The Gini index of 0.52 and Robin Hood index of 0.38 indicated significant inequality. Neighborhood-level educational attainment, car access, and population density best explained variation in neighborhood admission rates (R(2) = 0.55).

CONCLUSION

In a single year, asthma admission rates varied 88-fold across neighborhood quintiles in one county; a reduction of the county-wide admission rate to that of the bottom quintile would decrease annual admissions from 862 to 34. A rate of zero was present in 15 neighborhoods, which is evidence of what may be attainable.

Extermination strategies reported in the NYC Health and Nutrition Examination Survey, 2004: prevalence and predictors

It is likely that household extermination is a major source of pesticide exposure for urban residents. Little is known about the predictors of residential pest control strategies in urban areas, and greater knowledge of these may help identify who is at risk for higher pesticide exposure. Study data is from the 2004 NYC Health and Nutrition Examination Surveys, a cross-sectional, population-based study using a three-stage sampling scheme. Logistic regression was used to identify predictors of pesticide use overall, and of application strategy: (1) consumer-applied pesticides only, (2) use of a professional exterminator only, or (3) use of both. Consumer-applied extermination was more prevalent than professional or both professional and consumer (39.9% versus 27.8% and 15.9%, respectively, and non-exclusively). In multivariate models among those who used any extermination, consumer application was associated with age 60 years+, being black or Asian, and being widowed, divorced, or single. Lower income households were more likely to use both strategies, and less likely to use professional extermination only. Urban residents may benefit from targeted education on how and when to self-apply pesticides, and on best-practice pest control to avoid unnecessary pesticide exposure. Higher prevalence of consumer-applied and conjoint consumer and professionally applied extermination in low-income households may reflect both economic determinants of first recourse and higher neighborhood infestation levels.

Cost-consequence analysis of multimodal interventions with environmental components for pediatric asthma in the state of Maryland

BACKGROUND

Applied environmental strategies for asthma control are often expensive, but may save longer-term healthcare costs. Whether these savings outweigh additional costs of implementing these strategies is uncertain.

METHODS

We conducted a systematic review to estimate the expenditures and savings of environmental interventions for asthma in the state of Maryland. Direct costs included hospitalizations, emergency room, and clinic visits. Indirect expenditures included costs of lost work productivity and travel incurred during the usage of healthcare services. We used decision analysis, assuming a hypothetical cohort of the approximated 49,290 pediatric individuals in Maryland with persistent asthma, to compare costs and benefits of environmental asthma interventions against the standard of care (no intervention) from the societal perspective.

RESULTS

Three interventions among nine articles met the inclusion criteria for the systematic review: 1) environmental education using medical professionals; 2) education using non-medical personnel; and 3) multi-component strategy involving education with non-medical personnel, allergen-impermeable covers, and pest management. All interventions were found to be cost-saving relative to the standard of care. Home environmental education using non-medical professionals yielded the highest net savings of $14.1 million (95% simulation interval (SI): $-.283 million, $19.4 million), while the multi-component intervention resulted in the lowest net savings of $8.1 million (95% SI: $-4.9 million, $15.9 million). All strategies were most sensitive to the baseline number of hospitalizations in those not receiving targeted interventions for asthma.

CONCLUSIONS

Limited environmental reduction strategies for asthma are likely to be cost-saving to the healthcare system in Maryland and should be considered for broader scale-up in other economically similar settings.

Sensitization to rodents (mouse/rat) in urban atopic populations without occupational exposure living in Campania district (Southern Italy): a multicenter study

BACKGROUND

Up to now very few data on allergic sensitization to rodent allergens in Western Europe and Italy are available, and there are no information at district level.The aim of this report was to investigate clinical significance and characteristics of allergic sensitization to mouse/rat (M/Rt) allergens in atopic subjects living in Campania district (Southern Italy).

METHODS

Allergists from the whole Campania district were required to report the results of skin prick tests of at least 100 consecutive subjects. In 1,477 consecutive outpatients, we selected all subjects with an immediate skin reaction to M/Rt dander. Clinical history including a careful evaluation of the modality of exposure and the results of skin-prick tests (SPTs) were recorded.

RESULTS

Fifty seven patients were sensitized to M/Rt dander (5.78%). Two patients were mono-sensitized. Fourteen patients reported indoor conditions suggesting presence of rodents allergens at home. All patients exhibited low-moderate degree of SPT positivity to M/Rt. High frequency of concomitant allergic sensitization to dust mites was found.

CONCLUSIONS

Our results suggest that the role of allergic sensitization to rodents is not negligible in atopic subjects without occupational exposure living in Campania district area; these values are higher in comparison to those previously found in Naples area. Highly atopic individuals should be tested by SPTs/evaluation of serum specific IgE to rodents in the case they should begin an occupational exposure to M/Rt or keep these animals as pets.

Assessment of environmental cockroach allergen exposure

In the past, cockroach allergen exposure assessment mainly focused on settled dust in homes in low-income urban cities in the United States. That choice was not wrong; without measureable levels of cockroach allergen, it is difficult to show associations with any home characteristics, much less with health outcomes (e.g., allergy, asthma). However, recent studies in other suburban areas, schools, and other countries have elucidated the importance of cockroach allergen in these environments too. In addition, characterizing the underlying factors that give rise to cockroach allergen exposure (or protect against it) can lead to more targeted public health interventions. This review discusses different approaches to sampling indoor environments, interprets recent asthma and allergy studies, compares cockroach allergen levels from past studies with those of recent studies, and describes strategies for decreasing exposures.

Individual, housing, and neighborhood correlates of asthma among young urban children

Using data from a large cohort of urban children, this study identified multilevel correlates of asthma to determine whether neighborhood attributes remain associated with asthma after adjustment for individual level and immediate housing characteristics. A cross-sectional analysis was conducted using data from the Fragile Families and Child Well-being Study and its substudy, the In-Home Longitudinal Study of Pre-Schooled Age Children (n = 1,784). The primary outcome was asthma diagnosis by age 5. Sociodemographic measures were assessed via telephone survey, housing and block conditions recorded via direct observation, and neighborhood characteristics came from geocoded census tract data. After multivariable adjustment, non-Hispanic Black, Puerto Rican, or other Hispanic race, child's lack of insurance coverage, male gender, presence of allergies, the exterior condition of a child's home, mother's educational attainment, and the percent of the neighborhood population with a bachelor's degree remained significantly associated with having received an asthma diagnosis by age 5. The authors identified sociodemographic and economic factors at the individual, household, and neighborhood level which are correlates of childhood asthma in urban areas. After adjustment for more proximal characteristics, the effects of all neighborhood markers were minimal, with the exception of neighborhood education.

Measurement of gender inequality in neighbourhoods of Québec, Canada

Introduction

Few studies have measured gender inequality at levels lower than the country. We sought to develop neighbourhood indicators of gender inequality, and assess their ability to capture variability in gender inequality across Québec, Canada.

Methods

Aggregate 2001 census data for 11,564 neighbourhoods were obtained for men and women. Twelve indicators of gender inequality representing demographic/household characteristics, education, income, work/leisure, and political participation were selected. Neighbourhood-level gender inequality scores were computed for each indicator, and examined across parts of Québec (metropolitan areas, mid-sized cities, rural areas). Monte Carlo simulations were used to assess the ability of indicators to capture heterogeneity in gender inequality across neighbourhoods.

Results

Male-dominant neighbourhood-level gender inequality tended to be present for average employment income, labour force participation, employment rate, and employment in managerial positions. Female-dominant gender inequality tended to be present for divorce, single-headed households, and participation in unpaid housework, child and elderly care. Neighbourhood-level gender inequality tended to vary across metropolitan areas, mid-sized cities, and rural areas. Gender inequality scores also varied within these geographic areas. For example, there was greater income-related gender inequality in high than low income neighbourhoods. Monte Carlo simulations suggested that the variation in gender inequality across neighbourhoods was greater than expected with chance alone.

Conclusion

Neighbourhood-level gender inequality tended to be present in Québec, and varied across parts of the province. Greater awareness of and research on neighbourhood-level gender inequality may be warranted to inform gender policies in Québec and other nations.

Violent crime in San Antonio, Texas: an application of spatial epidemiological methods

Violent crimes are rarely considered a public health problem or investigated using epidemiological methods. But patterns of violent crime and other health conditions are often affected by similar characteristics of the built environment. In this paper, methods and perspectives from spatial epidemiology are used in an analysis of violent crimes in San Antonio, TX. Bayesian statistical methods are used to examine the contextual influence of several aspects of the built environment. Additionally, spatial regression models using Bayesian model specifications are used to examine spatial patterns of violent crime risk. Results indicate that the determinants of violent crime depend on the model specification, but are primarily related to the built environment and neighborhood socioeconomic conditions. Results are discussed within the context of a rapidly growing urban area with a diverse population.

Neighborhood Effects in Temporal Perspective

Theory suggests that neighborhood effects depend not only on where individuals live today, but also on where they lived in the past. Previous research, however, usually measured neighborhood context only once and did not account for length of residence, thereby understating the detrimental effects of long-term neighborhood disadvantage. This study investigates the effects of duration of exposure to disadvantaged neighborhoods on high school graduation. It follows 4,154 children in the PSID, measuring neighborhood context once per year from age 1 to 17. The analysis overcomes the problem of dynamic neighborhood selection by adapting novel methods of causal inference for time-varying treatments. In contrast to previous analyses, these methods do not "control away" the effect of neighborhood context operating indirectly through time-varying characteristics of the family, and thus they capture the full impact of a lifetime of neighborhood disadvantage. We find that sustained exposure to disadvantaged neighborhoods has a severe impact on high school graduation that is considerably larger than effects reported in prior research. Growing up in the most (compared to the least) disadvantaged quintile of neighborhoods is estimated to reduce the probability of graduation from 96% to 76% for black children, and from 95% to 87% for nonblack children.

Social environment and asthma: associations with crime and No Child Left Behind programmes

BACKGROUND

The relationship between asthma and socio-economic status remains unclear. The authors investigated how neighbourhood, school and community social environments were associated with incident asthma in Southern California schoolchildren.

METHODS

New-onset asthma was measured over 3 years of follow-up in the Children's Health Study cohort. Multilevel random-effects models assessed associations between social environments and asthma, adjusted for individual risk factors. At baseline, subjects resided in 274 census tracts (ie, neighbourhoods) and attended kindergarten or first grade in one of 45 schools distributed in 13 communities throughout Southern California. Neighbourhoods and communities were characterised by measures of deprivation, income inequality and racial segregation. Communities were further described by crime rates. Information on schools included whether a school received funding related to the Title 1 No Child Left Behind programme, which aims to reduce academic underachievement in disadvantaged populations.

RESULTS

Increased risk for asthma was observed in subjects attending schools receiving Title I funds compared with those from schools without funding (adjusted HR 1.71, 95% CI 1.14 to 2.58), and residing in communities with higher rates of larceny crime (adjusted HR 2.02, 95% CI 1.08 to 3.02 across the range of 1827 incidents per 100,000 population).

CONCLUSIONS

Risk for asthma was higher in areas of low socio-economic status, possibly due to unmeasured risk factors or chronic stress.

Indoor environment and children's health: recent developments in chemical, biological, physical and social aspects

Much research is being carried out into indoor exposure to harmful agents. This review focused on the impact on children's health, taking a broad approach to the indoor environment and including chemical, microbial, physical and social aspects. Papers published from 2006 onwards were reviewed, with regards to scientific context. Most of publications dealt with chemical exposure. Apart from the ongoing issue of combustion by-products, most of these papers concerned semi volatile organic compounds (such as phthalates). These may be associated with neurotoxic, reprotoxic or respiratory effects and may, therefore, be of particular interest so far as children are concerned. In a lesser extent, volatile organic compounds (such as aldehydes) that have mainly respiratory effects are still studied. Assessing exposure to metals is still of concern, with increasing interest in bioaccessibility. Most of the papers on microbial exposure focused on respiratory tract infections, especially asthma linked to allergens and bio-aerosols. Physical exposure includes noise and electromagnetic fields, and articles dealt with the auditory and non auditory effects of noise. Articles on radiofrequency electromagnetic fields mainly concerned questions about non-thermal effects and papers on extremely low-frequency magnetic fields focused on the characterization of exposure. The impact of the indoor environment on children's health cannot be assessed merely by considering the effect of these different types of exposure: this review highlights new findings and also discusses the interactions between agents in indoor environments and also with social aspects.

Are building-level characteristics associated with indoor allergens in the household?

Building-level characteristics are structural factors largely beyond the control of those who live in them. We explored whether building-level characteristics and indoor allergens in the household are related. We examined the relationship between building-level characteristics and indoor allergens: dust mite, cat, cockroach, and mouse. Building-level characteristics measured were presence of pests (seeing cockroaches and rodents), building type (public housing, buildings zoned commercially and residentially, and building size), and building condition (building age and violations). Allergen cutpoints were used for categorical analyses and defined as follows: dust mite: >0.25 μg/g; cat: >1 μg/g; cockroach: >1 U/g; mouse: >1.6 μg/g. In fully adjusted linear analyses, neither dust mite nor cat allergen were statistically significantly associated with any building-level characteristics. Cockroach allergen was associated with the presence of cockroaches (2.07; 95% CI, 1.23, 3.49) and living in public housing (2.14; 95% CI, 1.07, 4.31). Mouse allergen was associated with the presence of rodents (1.70; 95% CI, 1.29, 2.23), and building size: living in a low-rise (<8 floors; 0.60; 95% CI, 0.42, 0.87) or high-rise (8 + floors; 0.50; 95% CI, 0.29, 0.88; compared with house/duplex). In fully adjusted logistic analyses, cat allergen was statistically significantly associated with living in a high-rise (6.29; 95% CI, 1.51, 26.21; compared with a house/duplex). Mouse allergen was associated with living in public housing (6.20; 95% CI, 1.01, 37.95) and building size: living in a low-rise (0.16; 95% CI, 0.05, 0.52) or high-rise (0.06; 95% CI, 0.01, 0.50; compared with a house/duplex). Issues concerning building size and public housing may be particularly critical factors in reducing asthma morbidity. We suggest that future research explore the possible improvement of these factors through changes to building code and violations adherence, design standards, and incentives for landlords.