Ambient air toxics and asthma prevalence among a representative sample of US kindergarten-age children

Environmental Inequality in Estimated Cancer Risk from Airborne Toxic Exposure across United States Communities from 2011 to 2019

US Census Bureau data were matched to U.S. Environmental Protection Agency estimated cancer risks from airborne toxics from 2011 to 2019 to explore environmental inequality with nationwide census tract resolution. Spearman correlations showed modest associations between various socioeconomic status factors and estimated cancer risk. Multiple linear regression analyses show positive associations with increased estimated cancer risk (p < 0.05) for high proportions of Blacks in suburban and rural areas. A positive relationship with estimated cancer risk was found for increasing proportions of Asians and Hispanics in nonurban areas. Urban tracts that suffer from the highest estimated cancer risks were concentrated among the communities with a population of higher proportion of minorities. While environmental inequality seems to have improved across the examined years for certain demographics with respect to estimated cancer risk from air toxics, equity is far from achieved, and future work in identifying the sources of environmental inequality could help in achieving a more just environment.

Geographical Differences of Risk of Asthma and Allergic Rhinitis according to Urban/Rural Area: a Systematic Review and Meta-analysis of Cohort Studies

Several studies have demonstrated an association between the risk asthma/allergic rhinitis and the environment. However, to date, no systematic review or meta-analysis has investigated these factors. We conducted a systematic review and meta-analysis to assess the association between urban/rural living and the risk of asthma and allergic rhinitis. We searched the Embase and Medline databases for relevant articles and included only cohort studies to observe the effects of time-lapse geographical differences. Papers containing information on rural/urban residence and respiratory allergic diseases were eligible for inclusion. We calculated the relative risk (RR) and 95% confidence interval (CI) using a 2 × 2 contingency table and used random effects to pool data. Our database search yielded 8388 records, of which 14 studies involving 50,100,913 participants were finally included. The risk of asthma was higher in urban areas compared to rural areas (RR, 1.27; 95% CI, 1.12-1.44, p < 0.001), but not for the risk of allergic rhinitis (RR, 1.17; 95% CI, 0.87-1.59, p = 0.30). The risk of asthma in urban areas compared to rural areas was higher in the 0-6 years and 0-18 years age groups, with RRs of 1.21 (95% CI, 1.01-1.46, p = 0.04) and 1.35 (95% CI, 1.12-1.63, p = 0.002), respectively. However, there was no significant difference in the risk of asthma between urban and rural areas for children aged 0-2 years, with a RR of 3.10 (95% CI, 0.44-21.56, p = 0.25). Our study provides epidemiological evidence for an association between allergic respiratory diseases, especially asthma, and urban/rural living. Future research should focus on identifying the factors associated with asthma in children living in urban areas. The review was registered in PROSPERO (CRD42021249578).

Inequalities in Environmental Cancer Risk and Carcinogen Exposures: A Scoping Review

Background: Cancer is the leading cause of death in Canada and a major cause of death worldwide. Environmental exposure to carcinogens and environments that may relate to health behaviors are important to examine as they can be modified to lower cancer risks. Built environments include aspects such as transit infrastructure, greenspace, food and tobacco environments, or land use, which may impact how people move, exercise, eat, and live. While environments may play a role in overall cancer risk, exposure to carcinogens or healthier environments is not equitably spread across space. Exposures to carcinogens commonly concentrate among socially and/or economically disadvantaged populations. While many studies have examined inequalities in exposure or cancer risk, this has commonly been for one exposure. Methods: This scoping review collected and synthesized research that examines inequities in carcinogenic environments and exposures. Results: This scoping review found that neighborhoods with higher proportions of low-income residents, racialized people, or same-sex couples had higher exposures to carcinogens and environments that may influence cancer risk. There are currently four main themes in research studying inequitable exposures: air pollution and hazardous substances, tobacco access, food access, and other aspects of the built environment, with most research still focusing on air pollution. Conclusions: More work is needed to understand how exposures to these four areas intersect with other factors to reduce inequities in exposures to support longer-term goals toward cancer prevention.

Geographic and social economic disparities in the risk of exposure to ambient air respiratory toxicants at Oklahoma licensed early care and education facilities

BACKGROUND

Early life exposures to hazardous air pollutants has been associated with adverse asthma-related outcomes. Neighborhood-level social and economic factors play an essential role in the distribution of hazardous air pollutants and children spend a substantial amount of time at early care and education (ECE) facilities. While the indoor air quality of these facilities has been described, particularly for criteria air pollutants such as volatile organic compounds and particulate matter, little is known about the ambient air quality of ECE facilities.

OBJECTIVES

We conducted a cross-sectional study to estimate the ambient air quality of Oklahoma licensed ECE facilities and to explore associations between ambient air quality and select geographic predictors.

METHODS

We estimated ambient air quality using the total respiratory hazard quotient from the National Air Toxics Assessment according to the geographical location of licensed Oklahoma ECE facilities (N = 3184). We then determined whether urban and rural ECE facilities' air respiratory toxicant exposure risk differed by ECE facilities' neighborhood-level social and economic inequities including: 1) racial-ethnic minority community, 2) neighborhood socioeconomic status, and 3) residential segregation.

RESULTS

Urban ECE facilities in Hispanic segregated counties were five times more likely to be at risk of high air respiratory exposure, adjusted for integrated urban counties (p < 0.0001, 95% CI [3.824, 7.699]). Rural ECE facilities in African American segregated counties were nine times more likely to be at risk of high air respiratory toxicant exposure, adjusted for integrated rural counties (p < 0.0001, 95% CI [5.641, 15.928]).

CONCLUSION

We found geographically and socially disparate patterns of higher exposures to ambient air respiratory toxicants at Oklahoma ECE facilities. Safer siting policies and interventions are needed to mitigate air respiratory toxicant exposures, which may help to reduce asthma control disparities and improve respiratory health outcomes in Oklahoma ECE facilities.

Health Outcomes in Children Associated with Prenatal and Early-Life Exposures to Air Pollution: A Narrative Review

(1) Background: The developmental origins of health and disease (DOHaD) hypothesis links adverse fetal exposures with developmental mal-adaptations and morbidity later in life. Short- and long-term exposures to air pollutants are known contributors to health outcomes; however, the potential for developmental health effects of air pollution exposures during gestation or early-childhood have yet to be reviewed and synthesized from a DOHaD lens. The objective of this study is to summarize the literature on cardiovascular and metabolic, respiratory, allergic, and neuropsychological health outcomes, from prenatal development through early childhood, associated with early-life exposures to outdoor air pollutants, including traffic-related and wildfire-generated air pollutants. (2) Methods: We conducted a search using PubMed and the references of articles previously known to the authors. We selected papers that investigated health outcomes during fetal or childhood development in association with early-life ambient or source-specific air pollution exposure. (3) Results: The current literature reports that prenatal and early-childhood exposures to ambient and traffic-related air pollutants are associated with a range of adverse outcomes in early life, including cardiovascular and metabolic, respiratory and allergic, and neurodevelopmental outcomes. Very few studies have investigated associations between wildfire-related air pollution exposure and health outcomes during prenatal, postnatal, or childhood development. (4) Conclusion: Evidence from January 2000 to January 2022 supports a role for prenatal and early-childhood air pollution exposures adversely affecting health outcomes during development. Future studies are needed to identify both detrimental air pollutants from the exposure mixture and critical exposure time periods, investigate emerging exposure sources such as wildfire, and develop feasible interventional tools.

Children's exposure to vehicular pollution: Environmental injustice in Texas, USA

Distributive environmental justice research on children's exposure to vehicular pollution is underdeveloped and few empirical studies have been conducted in the US. This study seeks to address this gap by examining if socially disadvantaged children are disproportionately located in public school districts burdened by higher vehicular pollution in Texas-the second largest US state based on population size. Vehicular pollution exposure is measured using two variables: (1) an index developed by the US Environmental Protection Agency that combines traffic proximity and volume; and (2) outdoor concentrations of nitrogen dioxide (NO₂), a widely used proxy for traffic-related air pollution. These variables are linked to school district level data on socio-demographic characteristics of children obtained from the latest American Community Survey. Statistical analysis is based on multivariable generalized estimating equations that account for spatial clustering of school districts. Results reveal significantly greater traffic proximity and NO₂ exposure in Texas school districts with higher percentages of children, after controlling for clustering, population density, and other socio-demographic factors. Districts exposed to higher levels of traffic proximity and NO₂ exposure also contain significantly greater proportions of racial/ethnic minority, foreign-born, disabled, and socioeconomically vulnerable children. These findings highlight the urgent need to develop mitigation strategies for reducing vehicular pollution exposure, especially in districts with higher proportions of socially disadvantaged students that could be additionally burdened with limited resources. School districts represent a policy relevant analytic unit since school district boards can act as advocates for the environmental health of children and implement mitigation strategies for reducing pollution exposure.

Inequalities in Exposure to Ambient Air Neurotoxicants and Disparities in Markers of Neurodevelopment in Children by Maternal Nativity Status

Exposure levels to environmental pollutants vary significantly among different populations. These inequities in exposure to hazardous air pollutants (HAP) among different populations can contribute to disparities in neurodevelopmental outcomes. The aim of this study was to determine if exposure to HAP varies by maternal nativity status, a demographic marker often overlooked in the study of health disparities. We also assessed if those inequalities in exposure levels are associated with neurodevelopmental measures in young children. To do this, we obtained data from the Early Childhood Longitudinal Study-Birth cohort (ECLS-B), a nationally representative sample of children born in the U.S. in the year 2001 (n = 4750). Bayley’s Short Form-Research Edition (BSF-R) was used to measure cognitive development at 2 years of age. Using residential location at nine months of age, participants were assigned exposures to ten HAPs identified as potentially neurotoxic. Linear regression models were used to assess the joint effect of maternal nativity status and HAP exposure on neurodevelopment. Results showed inequities in exposure levels to ten different HAPs among the populations, as approximately 32% of children of foreign-born mothers were exposed to high levels of HAPs, compared to 21% of children born to U.S.-born mothers. Adjusting for socioeconomic factors, both isophorone exposure (a marker of industrial pollution) (−0.04, 95% CI, −0.12, 0.04) and maternal nativity status (−0.17, 95% CI, −0.27, −0.06) were independently associated with lower standardized BSF-R mental scores in children. Interaction between nativity status and isophorone was not statistically significant, but the change in mental scores associated with isophorone exposure was greater in children of foreign-born mothers compared to children of U.S.-born mothers (−0.12, vs. −0.03, p = 0.2). In conclusion, exposure to HAPs within the highest quartile was more commonly found among children of foreign-born mothers as compared to children of US-born mothers, indicating inequities in pollutant exposure by nativity status within urban populations. Exposures associated with nativity status may negatively contribute to children’s neurodevelopment.

Excess free fructose, apple juice, high fructose corn syrup and childhood asthma risk - the National Children's Study

BACKGROUND

Recent research provides consistent evidence that the unexplained doubling of childhood asthma prevalence (1980-1995), its continued climb and 2013 plateau, may be associated with the proliferation of high-fructose-corn-syrup (HFCS) in the US food supply. The HFCS used in soft drinks has been shown to contain a higher fructose-to-glucose ratio than previously thought. This coincides with a preference shift from orange to apple juice among young children. Apple juice naturally contains a high (≥2:1) fructose-to-glucose ratio. Thus, children have received high excess-free-fructose doses, the fructose type associated with fructose malabsorption. Unabsorbed excess-free-fructose in the gut may react with dietary proteins to form immunogens that bind asthma mediating receptors, and/or alter the microbiota towards a profile linked to lung disorders. Studies with longitudinal childhood data are lacking. Therefore, we tested the hypothesis that excess-free-fructose intake is associated with childhood asthma risk.

METHODS

Cox regression models were used to analyze prospective early childhood data (12-30 months of age) from the National Children's Study. Intake frequencies for soda/sports/fruit drinks, and 100% juices were used for analyses.

RESULTS

Greater consumption of 100% juice, soda/sports/fruit drinks, and any combination, was associated with ~two (P = 0.001), ~ 2.5 (P = 0.001), and ~ 3.5 times (P < 0.0001) higher asthma incidence.

CONCLUSIONS

Given these results, prior research and case-study evidence, it is reasonable to suggest that the two-fold higher asthma risk associated with 100% juice consumption is due to apple juice's high fructose-to-glucose ratio, and that the ~ 2.5/~ 3.5 times higher risk associated with soda/sports/fruit drinks intake is with the excess-free-fructose in HFCS.

Combined association of BTEX and material hardship on ADHD-suggestive behaviours among a nationally representative sample of US children

BACKGROUND

Previous research shows that environmental and social factors contribute to the development of attention-deficit/hyperactivity disorder (ADHD).

OBJECTIVE

To determine the relationship between early-life exposure to common ambient air pollutants (benzene, toluene, ethylbenzene, and xylene, also known as BTEX), household material hardship (a measure of socio-economic status), and ADHD-suggestive behaviours in kindergarten-age children.

METHODS

Pollutant exposure estimated from the 2002 National Air Toxics Assessment at each child's residential ZIP code at enrolment was linked to the Early Childhood Longitudinal Study Birth Cohort (n = 4650). Material hardship was assigned as a composite score of access to food, health care, and housing. Kindergarten teachers rated children's behaviours and activity in the classroom using a five-point Likert scale. Children with summary scores in the bottom decile were classified as displaying ADHD-suggestive behaviours. Logistic regression models were constructed to estimate the association between both BTEX exposure and material hardship on ADHD-suggestive behaviours.

RESULTS

The odds of displaying ADHD-suggestive behaviours were greater in children with combined high-level exposure to BTEX and in those experiencing material hardship (odds ratio 1.54, 95% confidence interval [CI] 1.12, 2.11, and OR 2.12, 95% CI 1.25, 3.59, respectively), adjusting for covariates. These associations were stronger when restricting the study population to urban areas. There was no evidence of interaction between early life BTEX exposure and material hardship, although the effects of BTEX exposure were slightly greater in magnitude among those with higher material hardship scores.

CONCLUSIONS

Children exposed to air toxics, material hardship, or both early in life are more likely to display signs of ADHD-suggestive behaviours as assessed by their kindergarten teachers. The associations between exposures to air pollution and to socio-economic hardship were observed in all children but were particularly strong in those living in urban areas.

A Model-to-Monitor Evaluation of 2011 National-Scale Air Toxics Assessment (NATA)

Environmental research has widely utilized the ambient concentrations of hazardous air pollutants (HAPs) modeled by the National-Scale Air Toxics Assessment (NATA) program; however, limited studies have evaluated the model's performance. This study aims to evaluate the model-to-monitor agreement of the 2011 NATA data with the monitoring data reported to the U.S. Environmental Protection Agency's (EPA) Air Quality System (AQS). Concentrations of 27 representative HAPs measured at 274 sites in the U.S. in 2011 were merged with NATA data by census tract. The comparison consisted of two steps for each HAP: first, the model-monitor difference at each site was compared with the limit of quantitation (LOQ); second, the modeled annual average was compared to the 95% confidence interval of the monitored annual average. Nationally, NATA could predict national medians of most HAPs well; however, it was unable to capture high concentrations. At individual sites, a large portion of model-monitor differences was below the LOQs, indicating they were unquantifiable. Model-to-monitor agreement displayed inconsistent patterns in terms of chemical groups or EPA regions and was strongly impacted by the comparison methods. The substantial non-agreements of NATA predictions with monitoring data require caution in environmental epidemiology and justice studies that are based on NATA data.

Environmental styrene exposure and neurologic symptoms in U.S. Gulf coast residents

BACKGROUND

Styrene is an established neurotoxicant at occupational levels, but effects at levels relevant to the general population have not been studied. We examined the neurologic effects of environmental styrene exposure among U.S. Gulf coast residents.

METHODS

We used National Air Toxics Assessment (NATA) 2011 estimates of ambient styrene concentrations to assign exposure levels for 21,962 non-diabetic Gulf state residents, and additionally measured blood styrene concentration in a subset of participants (n = 874). Neurologic symptoms, as well as detailed covariate information, were ascertained via telephone interview. We used log-binomial regression to estimate prevalence ratios (PR) and 95% confidence intervals (95% CI) for cross-sectional associations between both ambient and blood styrene levels and self-reported neurologic symptoms. We estimated associations independently for ten unique symptoms, as well as for the presence of any neurologic, central nervous system (CNS), or peripheral nervous system (PNS) symptoms. We also examined heterogeneity of associations with estimated ambient styrene levels by race and sex.

RESULTS

One-third of participants reported at least one neurologic symptom. The highest quartile of estimated ambient styrene was associated with one or more neurologic (PR, 1.12; 95% CI: 1.07,1.18), CNS (PR, 1.17; 95% CI: 1.11,1.25), and PNS (PR, 1.16; 95% CI: 1.09,1.25) symptom. Results were less consistent for biomarker analyses, but blood styrene level was suggestively associated with nausea (PR, 1.78; 95% CI: 1.04, 3.03). In stratified analyses, we observed the strongest effects among non-White participants.

CONCLUSIONS

Increasing estimated ambient styrene concentration was consistently associated with increased prevalence of neurologic symptoms. Associations between blood styrene levels and some neurologic symptoms were suggestive. Environmental styrene exposure levels may be sufficient to elicit symptomatic neurotoxic effects.

The combined effect of ambient ozone exposure and toxic air releases on hospitalization for asthma among children in Harris County, Texas

This study represents an analysis of the effect of exposure to ambient ozone and toxic air releases on hospitalization for asthma among children in Harris County, Texas. Our study identified temporal and spatial variations in asthma hospitalization across the study region and explored the combined effect of exposure to ambient ozone and air toxics on asthma hospitalization. Asthma hospitalization hot spots and clusters were mostly not located on zip codes with reported high quantities of total air releases of chemical pollutants. There was no significant interaction between ambient ozone exposure and toxic air releases relative to asthma hospitalization. The major predictor of asthma hospitalization was season, with hospitalization rate per 10,000 people for asthma being highest in winter period when ozone levels are usually lowest.

Asthma prevalence and school-related hazardous air pollutants in the US-México border area

BACKGROUND

Asthma is the most common chronic disease in children and has been linked to high levels of ambient air pollution and certain hazardous air pollutants (HAPs). Outdoor pollutants such as benzene, released by car emissions, and organic chemicals found in diesel exhaust, as well as particles and irritant gases, including nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and ozone (O₃), contribute to an increased prevalence of respiratory diseases such as asthma.

OBJECTIVES

The objectives of this study were to: 1) conduct a screening survey to identify high risk for asthma among school-age children in Hidalgo County, and, 2) study the potential health impact of school-related exposure to HAPs pertaining to asthma risk.

METHODS

We carried out a quantitative cross-sectional study combining a school-based asthma screening survey across 198 schools in Hidalgo County, Texas, with information on school neighborhood environments, including census tract-level information on hazardous air pollutants (HAPs) and socioeconomic status (SES) in the respective school neighborhoods. HAPs levels were assessed based on the EPA 2011 National-Scale Air Toxics Assessment (NATA) while SES information was assessed using data from the 2010-2014 American Community Survey.

RESULTS

2930 students completed the asthma screening survey and results showed an overall asthma prevalence of 9.4%, slightly higher than the national and state prevalence. Participants in the 14-18 years old age group showed a much higher asthma prevalence of 16.7%. When assessing school-neighborhood characteristics, our results revealed no significant differences in asthma prevalence across census tracts with different SES levels. For HAPs, in the single-pollutant model, chlorine levels showed a significant linear trend for prevalence of asthma (p=0.03) while hydrochloric acid had a marginally significant linear trend (p=0.08). The association with chlorine remained significant in the multi-pollutant model.

CONCLUSIONS

Asthma prevalence among school-age children in Hidalgo County, Texas, is 9.4%, which is slightly higher than the state rate, especially among young adults, ages 14-18 years who had an asthma rate of 16.7%. Results support an association between exposures to school-neighborhood HAPs and risk for pediatric asthma, especially as related to chlorine. No significant effects of school-level SES on asthma risk were observed.

Maternal Obesity, Gestational Weight Gain, and Asthma in Offspring

INTRODUCTION

Obesity is common among women of childbearing age; intrauterine exposure to maternal obesity or gestational weight gain may influence the development of asthma in early childhood. We examined the relationships of maternal obesity and gestational weight gain with asthma in offspring.

METHODS

We used data from the Early Childhood Longitudinal Study-Birth Cohort, which has a nationally representative sample of children followed from birth in 2001 through age 4 (n = 6,450). Asthma was based on parental report of a medical professional's diagnosis. We used generalized estimating equation binomial models to compute adjusted odds ratios (ORs) of childhood asthma with maternal obesity and 4 measures of gestational weight gain.

RESULTS

Compared with children of normal-weight mothers, children of obese mothers had increased risk of asthma (adjusted OR, 1.63; 95% confidence interval [CI], 1.26-2.12) by age 4, and children born to overweight mothers had similar risk (adjusted OR, 1.25; 95% CI, 0.99-1.59). Extreme-low weight gain (<5 kg) and extreme-high weight gain (≥25 kg) were associated with increased risk of asthma; however, the following measures were not significant predictors of asthma: meeting gestational weight gain recommendations of the Institute of Medicine, total gestational weight gain, and weekly rate of weight gain in the second and third trimesters.

CONCLUSION

Extreme-low or extreme-high gestational weight gain and maternal obesity are risk factors for early childhood asthma, further evidence of the long-term impact of intrauterine exposure on children and the need to target preconception care to improve child health indicators.

Using machine learning to identify air pollution exposure profiles associated with early cognitive skills among U.S. children

Data-driven machine learning methods present an opportunity to simultaneously assess the impact of multiple air pollutants on health outcomes. The goal of this study was to apply a two-stage, data-driven approach to identify associations between air pollutant exposure profiles and children's cognitive skills. Data from 6900 children enrolled in the Early Childhood Longitudinal Study, Birth Cohort, a national study of children born in 2001 and followed through kindergarten, were linked to estimated concentrations of 104 ambient air toxics in the 2002 National Air Toxics Assessment using ZIP code of residence at age 9 months. In the first-stage, 100 regression trees were learned to identify ambient air pollutant exposure profiles most closely associated with scores on a standardized mathematics test administered to children in kindergarten. In the second-stage, the exposure profiles frequently predicting lower math scores were included within linear regression models and adjusted for confounders in order to estimate the magnitude of their effect on math scores. This approach was applied to the full population, and then to the populations living in urban and highly-populated urban areas. Our first-stage results in the full population suggested children with low trichloroethylene exposure had significantly lower math scores. This association was not observed for children living in urban communities, suggesting that confounding related to urbanicity needs to be considered within the first-stage. When restricting our analysis to populations living in urban and highly-populated urban areas, high isophorone levels were found to predict lower math scores. Within adjusted regression models of children in highly-populated urban areas, the estimated effect of higher isophorone exposure on math scores was -1.19 points (95% CI -1.94, -0.44). Similar results were observed for the overall population of urban children. This data-driven, two-stage approach can be applied to other populations, exposures and outcomes to generate hypotheses within high-dimensional exposure data.

The Combined Influence of Air Pollution and Home Learning Environment on Early Cognitive Skills in Children

Cognitive skills are one component of school readiness that reflect a child’s neurodevelopment and are influenced by environmental and social factors. Most studies assess the impact of these factors individually, without taking into consideration the complex interactions of multiple factors. The objective of this study was to examine the joint association of markers of environmental pollution and of social factors on early cognitive skills in an urban cohort of children. For this, we chose isophorone in ambient air as a marker of industrial air pollution. Low quality home learning environments was chosen as a marker of the social factors contributing to cognitive development. Using a subpopulation from the Early Childhood Longitudinal Study, Birth Cohort (N = 4050), isophorone exposure was assigned using the 2002 National Air Toxics Assessment. Home learning environment was assessed with a modified version of the Home Observation for Measurement of the Environment (HOME) Inventory, and standardized math assessment scores were used as a measure of early cognitive skills. Multiple linear regression was used to estimate the effect of both exposures on math scores. After adjustment for confounders, children living in areas with ambient isophorone in the upper quintile of exposure (>0.49 ng/m³) had math scores that were 1.63 points lower than their less exposed peers [95% CI: −2.91, −0.34], and children with lower HOME scores (at or below 9 out of 12) had math scores that were 1.20 points lower than children with better HOME scores [95% CI: −2.30, −0.10]. In adjusted models accounting for identified confounders and both exposures of interest, both high isophorone exposure and low HOME score remained independently associated with math scores [−1.48, 95% CI: −2.79, −0.18; −1.05, 95% CI: −2.15, 0.05, respectively]. There was no statistical evidence of interaction between the two exposures, although children with both higher isophorone exposure and a low HOME score had a decrement in math scale score beyond the additive effect of each exposure. This was primarily observed among male children. These findings suggest that aspects of both the physical and social environments are independently associated with children’s early cognitive skills. Future research aiming to improve children’s early cognitive skills and subsequent school readiness should address both domains.

Prevalence and Occupational and Environmental Risk Factors of Self-Reported Asthma: Evidence from a Cross-Sectional Survey in Seven Chinese Cities

OBJECTIVE

Asthma is one of the most common chronic diseases and associated with significant morbidity and mortality. However, few data on occupational and environmental risk factors of asthma are available, particularly in Asian adults. Based on a national cross-sectional survey, we assessed the prevalence and risk factors of asthma in Chinese adults.

METHODS

A total of 9974 participants aged 15 years and over in seven Chinese cities were selected using a stratified four-stage random sampling. All participants were interviewed face-to-face in their homes using a standardized self-administered questionnaire. Multivariate logistic regression analyses were adopted to determine various risk factors for asthma.

RESULTS

The prevalence of self-reported lifetime asthma was 2.46% among the entire adult population, 3.02% among males and 1.93% among females. The prevalence varied by age group, ethnicity, marital status, education, and floor space per person (p < 0.05). After adjusting for socio-demographic variables and smoking, we found independent occupational and environmental determinants of asthma, including a clearance-related job (OR = 2.28, 95%CI: 1.07-4.89), occupational exposure to industrial or occupational poisonous gas (OR = 4.21, 95%CI: 2.43-7.30), having large amounts of carpet in the workplace (OR = 2.61, 95%CI: 1.20-5.69) and using coal for cooking (OR = 2.65, 95%CI: 1.26-5.57).

CONCLUSIONS

Asthma is a serious public health problem in China. Our study provides important updated information on the prevalence of asthma and its associated risk factors, which may help us better understand the epidemiology of asthma and prevent this disorder.

Asthma exacerbations and traffic: examining relationships using link-based traffic metrics and a comprehensive patient database

BACKGROUND

The Rochester Epidemiology Project (REP) is a unique community-based medical record data linkage system that provides individual patient address, diagnosis and visit information for all hospitalizations, as well as emergency department, urgent care and outpatient clinic visits for asthma. Proximity to traffic is known to be associated with asthma exacerbations and severity. Our null hypothesis was that there is no association between residential proximity to traffic and asthma exacerbations over eleven years of REP data.

METHODS

Spatial coordinates of the homes of 19,915 individuals diagnosed with asthma were extracted from the REP database. Three metrics of traffic exposure at residences were calculated from link-based traffic count data. We used exploratory statistics as well as logistic and Poisson regression to examine associations between three traffic metrics at the home address and asthma exacerbations.

RESULTS

Asthma exacerbations increased as traffic levels near the home increased. Proximity to traffic was a significant predictor of asthma exacerbations in logistic and Poisson regressions controlling for age, gender and block group poverty.

CONCLUSIONS

Over eleven years in a comprehensive county-wide data set of asthma patients, and after controlling for demographic effects, we found evidence that living in proximity to traffic increased the risk of asthma exacerbations.

Short-term association between particular matter air pollution and pediatric clinical visits for wheezing in a subarea of Shanghai

To assess the association between the concentration of ambient particulate matter (PM) and the pediatric clinical visits for wheezing among children under 3 years old, data of daily air pollutants (PM2.5, PM10, NO2, SO2, CO), meteorological reports, along with the number of daily clinical visits of the children with wheezing at the Pediatric Department of Shanghai Renji Hospital (South Campus) were collected from January through December 2014. Correlation between the levels of air pollutants and the number of clinical patients for wheezing were analyzed by a time series analysis with a generalized addictive model (GAM). During the study period, the daily average concentrations of PM2.5, PM10, NO2, SO2, and CO were 51.84 ± 32.51, 72.69 ± 41.15, 43.25 ± 18.07, 17.45 ± 10.42, and 0.82 ± 0.26 μg/m(3), respectively, which were abnormally higher compared to the standard defined by the Chinese Ministry of Environment Protection. The average number of daily clinical patients with wheezing was 23 ± 14 persons/day. The number of clinical visit by children with wheezing was significantly correlated with concentration of PM2.5 or PM10 when the effect of SO2 and NO2 was adjusted (P < 0.05). It was also found that exposure-response relationship was a linear non-threshold mode when it was analyzed by the GAM, and the percent of the clinical visits of children with wheezing increased from 0 to nearly 20 % with every interquartile increase of PM2.5. The visiting number of children at a pediatric outpatient clinic increased due to the increase of PM2.5 in Pujiang, Shanghai, China.

The importance of toxicity in determining the impact of hazardous air pollutants on the respiratory health of children in Tennessee

Respiratory diseases, exacerbated through point source pollution, are currently among the leading causes of hospitalization of children in the United States. This paper investigates the relationship between the proximity of hazardous air pollutants (HAPs) emitted from Toxic Release Inventory (TRI) facilities and the number of children diagnosed in hospitals with a respiratory disease in Tennessee. The importance of controlling for toxicity of those HAPs is of particular interest. Hospital discharge, socioeconomic, TRI emission, and HAP toxicity data are used to estimate, via Generalized Linear Methods, a logistic regression model describing the relationship between the percent of children living in a zip code area treated for respiratory illness and the average annual emissions over the previous 10 years of HAPs from TRI sites in that area. Controlling for area socioeconomic characteristics, we find that accounting for toxicity is important in uncovering the relationship between HAP emissions and respiratory health of children. A one standard deviation increase in toxicity-weighted emissions per 100 square miles is associated with an increase in the number of children diagnosed with asthma (chronic bronchitis) by about 1205 (260). The evidence suggests that, with a goal to improving children's respiratory health, monitoring the toxicity of chemicals being emitted is at least as important as simply monitoring total emission levels. This suggests that the EPA should consider making efforts toward establishing toxicity adjusted emission guidelines.

Effects of air pollution on human health and practical measures for prevention in Iran

Air pollution is a major concern of new civilized world, which has a serious toxicological impact on human health and the environment. It has a number of different emission sources, but motor vehicles and industrial processes contribute the major part of air pollution. According to the World Health Organization, six major air pollutants include particle pollution, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. Long and short term exposure to air suspended toxicants has a different toxicological impact on human including respiratory and cardiovascular diseases, neuropsychiatric complications, the eyes irritation, skin diseases, and long-term chronic diseases such as cancer. Several reports have revealed the direct association between exposure to the poor air quality and increasing rate of morbidity and mortality mostly due to cardiovascular and respiratory diseases. Air pollution is considered as the major environmental risk factor in the incidence and progression of some diseases such as asthma, lung cancer, ventricular hypertrophy, Alzheimer's and Parkinson's diseases, psychological complications, autism, retinopathy, fetal growth, and low birth weight. In this review article, we aimed to discuss toxicology of major air pollutants, sources of emission, and their impact on human health. We have also proposed practical measures to reduce air pollution in Iran.

Acrolein and asthma attack prevalence in a representative sample of the United States adult population 2000-2009

Background

Acrolein is an air toxic and highly potent respiratory irritant. There is little epidemiology available, but US EPA estimates that outdoor acrolein is responsible for about 75 percent of non-cancer respiratory health effects attributable to air toxics in the United States, based on the Agency's 2005 NATA (National-Scale Air Toxics Assessment) and acrolein's comparatively potent inhalation reference concentration of 0.02 µg/m³.

Objectives

Assess the association between estimated outdoor acrolein exposure and asthma attack reported by a representative cross-sectional sample of the adult United States population.

Methods

NATA 2005 chronic outdoor acrolein exposure estimates at the census tract were linked with residences oif adults (≥18 years old) in the NHIS (National Health Interview Survey) 2000 – 2009 (n = 271,348 subjects). A sample-weighted logistic regression model characterized the association between the prevalence of reporting at least one asthma attack in the 12 months prior to survey interview and quintiles of exposure to outdoor acrolein, controlling for potential confounders.

Results

In the highest quintile of outdoor acrolein exposure (0.05 – 0.46 µg/m³), there was a marginally significant increase in the asthma attack pOR (prevalence-odds ratio [95% CI]  = 1.08 [0.98∶1.19]) relative to the lowest quintile. The highest quintile was also associated with a marginally significant increase in prevalence-odds (1.13 [0.98∶1.29]) in a model limited to never smokers (n = 153,820).

Conclusions

Chronic exposure to outdoor acrolein of 0.05 – 0.46 µg/m³ appears to increase the prevalence-odds of having at least one asthma attack in the previous year by 8 percent in a representative cross-sectional sample of the adult United States population.