Ketan Shankardass

Childhood Incident Asthma and Traffic-Related Air Pollution at Home and School

Background Traffic-related air pollution has been associated with adverse cardiorespiratory effects, including increased asthma prevalence. However, there has been little study of effects of traffic exposure at school on new-onset asthma. Objectives We evaluated the relationship of new-onset asthma with traffic-related pollution near homes and schools. Methods Parent-reported physician diagnosis of new-onset asthma (n = 120) was identified during 3 years of follow-up of a cohort of 2,497 kindergarten and first-grade children who were asthma- and wheezing-free at study entry into the Southern California Children’s Health Study. We assessed traffic-related pollution exposure based on a line source dispersion model of traffic volume, distance from home and school, and local meteorology. Regional ambient ozone, nitrogen dioxide (NO2), and particulate matter were measured continuously at one central site monitor in each of 13 study communities. Hazard ratios (HRs) for new-onset asthma were scaled to the range of ambient central site pollutants and to the residential interquartile range for each traffic exposure metric. Results Asthma risk increased with modeled traffic-related pollution exposure from roadways near homes [HR 1.51; 95% confidence interval (CI), 1.25–1.82] and near schools (HR 1.45; 95% CI, 1.06–1.98). Ambient NO2 measured at a central site in each community was also associated with increased risk (HR 2.18; 95% CI, 1.18–4.01). In models with both NO2 and modeled traffic exposures, there were independent associations of asthma with traffic-related pollution at school and home, whereas the estimate for NO2 was attenuated (HR 1.37; 95% CI, 0.69–2.71). Conclusions Traffic-related pollution exposure at school and homes may both contribute to the development of asthma.

Traffic-Related Air Pollution and Asthma Onset in Children: A Prospective Cohort Study with Individual Exposure Measurement

Background The question of whether air pollution contributes to asthma onset remains unresolved. Objectives In this study, we assessed the association between asthma onset in children and traffic-related air pollution. Methods We selected a sample of 217 children from participants in the Southern California Children’s Health Study, a prospective cohort designed to investigate associations between air pollution and respiratory health in children 10–18 years of age. Individual covariates and new asthma incidence (30 cases) were reported annually through questionnaires during 8 years of follow-up. Children had nitrogen dioxide monitors placed outside their home for 2 weeks in the summer and 2 weeks in the fall–winter season as a marker of traffic-related air pollution. We used multilevel Cox models to test the associations between asthma and air pollution. Results In models controlling for confounders, incident asthma was positively associated with traffic pollution, with a hazard ratio (HR) of 1.29 [95% confidence interval (CI), 1.07–1.56] across the average within-community interquartile range of 6.2 ppb in annual residential NO2. Using the total interquartile range for all measurements of 28.9 ppb increased the HR to 3.25 (95% CI, 1.35–7.85). Conclusions In this cohort, markers of traffic-related air pollution were associated with the onset of asthma. The risks observed suggest that air pollution exposure contributes to new-onset asthma.

Parental stress increases the effect of traffic-related air pollution on childhood asthma incidence

Exposure to traffic-related pollution (TRP) and tobacco smoke have been associated with new onset asthma in children. Psychosocial stress-related susceptibility has been proposed to explain social disparities in asthma. We investigated whether low socioeconomic status (SES) or high parental stress modified the effect of TRP and in utero tobacco smoke exposure on new onset asthma. We identified 2,497 children aged 5–9 years with no history of asthma or wheeze at study entry (2002–2003) into the Childrens Health Study, a prospective cohort study in southern California. The primary outcome was parental report of doctor-diagnosed new onset asthma during 3 years of follow-up. Residential exposure to TRP was assessed using a line source dispersion model. Information about maternal smoking during pregnancy, parental education (a proxy for SES), and parental stress were collected in the study baseline questionnaire. The risk of asthma attributable to TRP was significantly higher for subjects with high parental stress (HR 1.51 across the interquartile range for TRP; 95% CI 1.16–1.96) than for subjects with low parental stress (HR 1.05, 95% CI 0.74–1.49; interaction P value 0.05). Stress also was associated with larger effects of in utero tobacco smoke. A similar pattern of increased risk of asthma was observed among children from low SES families who also were exposed to either TRP or in utero tobacco smoke. These results suggest that children from stressful households are more susceptible to the effects of TRP and in utero tobacco smoke on the development of asthma.

Parental Stress Increases the Detrimental Effect of Traffic Exposure on Children's Lung Function

RATIONALE Emerging evidence indicates that psychosocial stress enhances the effect of traffic exposure on the development of asthma. OBJECTIVES We hypothesized that psychosocial stress would also modify the effect of traffic exposure on lung function deficits. METHODS We studied 1,399 participants in the Southern California Childrens Health Study undergoing lung function testing (mean age, 11.2 yr). We used hierarchical mixed models to assess the joint effect of traffic-related air pollution and stress on lung function. MEASUREMENTS AND MAIN RESULTS Psychosocial stress in each childs household was assessed based on parental response to the perceived stress scale (range, 0-16) at study entry. Exposures to nitric oxide, nitrogen dioxide, and total oxides of nitrogen (NOx), surrogates of the traffic-related pollution mixture, were estimated at schools and residences based on a land-use regression model. Among children from high-stress households (parental perceived stress scale > 4) deficits in FEV1 of 4.5 (95% confidence interval, -6.5 to -2.4) and of 2.8% (-5.7 to 0.3) were associated with each 21.8 ppb increase in NOx at homes and schools, respectively. These pollutant effects were significantly larger in the high-stress compared with lower-stress households (interaction P value 0.007 and 0.05 for residential and school NOx, respectively). No significant NOx effects were observed in children from low-stress households. A similar pattern of association was observed for FVC. The observed associations for FEV1 and FVC remained after adjusting for sociodemographic factors and after restricting the analysis to children who do not have asthma. CONCLUSIONS A high-stress home environment is associated with increased susceptibility to lung function effects of air pollution both at home and at school.

A scoping review of intersectoral action for health equity involving governments

ObjectivesWe carried out a scoping review to identify and describe scholarly and grey literature referring to global cases of intersectoral action for health equity featuring a central role for governments.MethodsThe scoping review process systematically identified articles describing one or more cases of intersectoral action. Each article was then described in terms of the context of initiation, as well as the strategies, actors, tools and structures used to implement these initiatives.Results128 unique articles were found describing intersectoral action across 43 countries. A majority of the cases appear to have initiated in the last decade. A variety of approaches were used to carry out intersectoral action, but articles varied in the richness of information included to describe different aspects of these initiatives.ConclusionWith this examination of cases across multiple countries and contexts, we can begin to clarify how intersectoral approaches to health equity have been used; however, the description of these complex, multi-actor processes in the published documents was generally superficial and sometimes entirely absent and improvements in such documentation in future publications is warranted. Richer sources of information such as interviews may facilitate a more comprehensive understanding from the perspective of multiple sectors involved.

Glossary for the implementation of Health in All Policies (HiAP)

Health in All Policies (HiAP) is becoming increasingly popular as a governmental strategy to improve population health by coordinating action across health and non-health sectors. A variety of intersectoral initiatives may be used in HiAP that frame health determinants as the bridge between policies and health outcomes. The purpose of this glossary is to present concepts and terms useful in understanding the implementation of HiAP as a cross-sectoral policy. The concepts presented here were applied and elaborated over the course of case studies of HiAP in multiple jurisdictions, which used key informant interviews and the systematic review of literature to study the implementation of specific HiAP initiatives.

Strengthening the implementation of Health in All Policies: a methodology for realist explanatory case studies.

To address macro-social and economic determinants of health and equity, there has been growing use of intersectoral action by governments around the world. Health in All Policies (HiAP) initiatives are a special case where governments use cross-sectoral structures and relationships to systematically address health in policymaking by targeting broad health determinants rather than health services alone. Although many examples of HiAP have emerged in recent decades, the reasons for their successful implementation--and for implementation failures--have not been systematically studied. Consequently, rigorous evidence based on systematic research of the social mechanisms that have regularly enabled or hindered implementation in different jurisdictions is sparse. We describe a novel methodology for explanatory case studies that use a scientific realist perspective to study the implementation of HiAP. Our methodology begins with the formulation of a conceptual framework to describe contexts, social mechanisms and outcomes of relevance to the sustainable implementation of HiAP. We then describe the process of systematically explaining phenomena of interest using evidence from literature and key informant interviews, and looking for patterns and themes. Finally, we present a comparative example of how Health Impact Assessment tools have been utilized in Sweden and Quebec to illustrate how this methodology uses evidence to first describe successful practices for implementation of HiAP and then refine the initial framework. The methodology that we describe helps researchers to identify and triangulate rich evidence describing social mechanisms and salient contextual factors that characterize successful practices in implementing HiAP in specific jurisdictions. This methodology can be applied to study the implementation of HiAP and other forms of intersectoral action to reduce health inequities involving multiple geographic levels of government in diverse settings.

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 Childrens 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.

Factors Influencing whether Children Walk to School

Few studies have simultaneously evaluated multiple levels of influence on whether children walk to school. A large cohort of 4338 subjects from 10 communities was used to identify the determinants of walking through (1) a one-level logistic regression model for individual-level variables and (2) a two-level mixed regression model for individual and school-level variables. Walking rates were positively associated with home-to-school proximity, greater age, and living in neighborhoods characterized by lower traffic density. Greater land use mix around the home was, however, associated with lower rates of walking. Rates of walking to school were also higher amongst recipients of the Free and Reduced Price Meals Program and attendees of schools with higher percentage of English language learners. Designing schools in the same neighborhood as residential districts should be an essential urban planning strategy to reduce walking distance to school. Policy interventions are needed to encourage children from higher socioeconomic status families to participate in active travel to school and to develop walking infrastructures and other measures that protect disadvantaged children.

Social welfare matters: A realist review of when, how, and why unemployment insurance impacts poverty and health

The recent global recession and concurrent rise in job loss makes unemployment insurance (UI) increasingly important to smooth patterns of consumption and keep households from experiencing extreme material poverty. In this paper, we undertake a realist review to produce a critical understanding of how and why UI policies impact on poverty and health in different welfare state contexts between 2000 and 2013. We relied on literature and expert interviews to generate an initial theory and set of propositions about how UI might alleviate poverty and mental distress. We then systematically located and synthesized peer-review studies to glean supportive or contradictory evidence for our initial propositions. Poverty and psychological distress, among unemployed and even the employed, are impacted by generosity of UI in terms of eligibility, duration and wage replacement levels. Though unemployment benefits are not intended to compensate fully for a loss of earnings, generous UI programs can moderate harmful consequences of unemployment.