Traffic and outdoor air pollution levels near residences and poorly controlled asthma in adults

Association between air pollutant exposure, body water distribution and sleep disorder indices in individuals with low-arousal-threshold obstructive sleep apnoea

BACKGROUND

Air pollution may alter body water distribution, it may also be linked to low-arousal-threshold obstructive sleep apnoea (low-ArTH OSA). Here, we explored the mediation effects of air pollution on body water distribution and low-ArTH OSA manifestations.

METHODS

In this retrospective study, we obtained sleep centre data from healthy participants and patients with low-ArTH OSA (N=1924) in northern Taiwan. Air pollutant exposure at different time intervals (1, 3, 6 and 12 months) was estimated using the nearest station estimation method, and government air-quality data were also obtained. Regression models were used to assess the associations of estimated exposure, sleep disorder indices and body water distribution with the risk of low-ArTH OSA. Mediation analysis was performed to explore the relationships between air pollution, body water distribution and sleep disorder indices.

RESULTS

First, exposure to particulate matter (PM) with a diameter of ≤10 µm (PM10) for 1 and 3 months and exposure to PM with a diameter of ≤2.5 µm (PM2.5) for 3 months were significantly associated with the Apnoea-Hypopnoea Index (AHI), Oxygen Desaturation Index (ODI), Arousal Index (ArI) and intracellular-to-extracellular water ratio (I-E water ratio). Significant associations were observed between the risk of low-ArTH OSA and 1- month exposure to PM10 (OR 1.42, 95% CI 1.09 to 1.84), PM2.5 (OR 1.33, 95% CI 1.02 to 1.74) and ozone (OR 1.27, 95% CI 1.01 to 1.6). I-E water ratio alternation caused by 1-month exposure to PM10 and 3-month exposure to PM2.5 and PM10 had partial mediation effects on AHI and ODI.

CONCLUSION

Air pollution can directly increase sleep disorder indices (AHI, ODI and ArI) and alter body water distribution, thus mediating the risk of low-ArTH OSA.

Update on Climate Change: Its Impact on Respiratory Health at Work, Home, and at Play

Climate change is a crisis of vast proportions that has serious implications for pulmonary health. Increasing global temperatures influence respiratory health through extreme weather events, wildfires, prolonged allergy seasons, and worsening air pollution. Children, elderly patients, and patients with underlying lung disease are at elevated risk of complications from these effects of climate change. This paper summarizes the myriad ways in which climate change affects the respiratory health of patients at home and in outdoor environments and outlines measures for patients to protect themselves.

Identifying and evaluating school environmental health indicators

Children's health, attendance, and academic performance may be affected by school environmental hazards. While prior studies evaluated home environment and health, few have evaluated indicators of school in-/outdoor environment and health. This study addresses this knowledge gap by systematically reviewing and evaluating outdoor and indoor indicators of school environment and student's health and performance in New York State (NYS). We also evaluate statistical methodologies to address highly correlated indicators and integrate multiple exposures. Multiple school environmental indicators were identified from various existing NYS datasets. We summarized data sources, completeness, geographic and temporal coverage, and data quality for each indicator. Each indicator was evaluated by scientific basis/relevance, analytic soundness/feasibility, and interpretation/utility, and validated using objective NYS data. Finally, advanced variable selection methods were described and discussed. We have identified and evaluated multiple school environmental health indicators. It was found that mold and moisture problems, ventilation problems, ambient ozone, and PM_2.5 levels are among the top priorities of school environmental issues/indicators in NYS, which were also consistent while using NYS data. Choice of best variable selection method should be made based on the research questions and data characteristics. The school environmental health indicators identified, and variable selection methods evaluated, in this study could be used by other researchers to help school officials and policy makers initiate prevention programs.

Air Quality Index and air quality awareness among adults in the United States

BACKGROUND

Information about local air quality is reported across the United States using air quality alerts such as the Environmental Protection Agency's Air Quality Index. However, the role of such alerts in raising awareness of air quality is unknown. We conducted this study to evaluate associations between days with Air Quality Index ≥101, corresponding to a categorization of air quality as unhealthy for sensitive groups, unhealthy, very unhealthy, or hazardous, and air quality awareness among adults in the United States.

METHODS

Data from 12,396 respondents to the 2016-2018 ConsumerStyles surveys were linked by geographic location and survey year to daily Air Quality Index data. We evaluated associations between the number of days in the past year with Air Quality Index ≥101 and responses to survey questions about awareness of air quality alerts, perception of air quality, and changes in behavior to reduce air pollution exposure using logistic regression.

RESULTS

Awareness of air quality alerts (prevalence ratio [PR] = 1.23; 95% confidence interval [CI] = 1.15, 1.31), thinking/being informed air quality was bad (PR = 2.02; 95% CI = 1.81, 2.24), and changing behavior (PR = 2.27; 95% CI = 1.94, 2.67) were higher among respondents living in counties with ≥15 days with Air Quality Index ≥101 than those in counties with zero days in the past year with Air Quality Index ≥101. Each aspect of air quality awareness was higher among adults with than without asthma, but no differences were observed by heart disease status. Across quintiles of the number of days with Air Quality Index ≥101, air quality awareness increased among those with and without selected respiratory and cardiovascular diseases.

CONCLUSIONS

Among U.S. adults, air quality awareness increases with increasing days with alerts of unhealthy air. These findings improve our understanding of the extent to which air quality alerts prompt people to take actions to protect their health amidst poor air quality.

Climate Change and Underserved Communities

Climate change is the greatest global health threat of the twenty-first century, yet it is not widely understood as a health hazard by primary care providers in the United States. Aside from increasing displacement of populations and acute trauma resulting from increasing frequency of natural disasters, the impact of climate change on temperature stress, vector-borne illnesses, cardiovascular and respiratory illnesses, and mental health is significant, with disproportionate impact on underserved and marginalized populations. Primary care providers must be aware of the impact of climate change on the health of their patients and advocate for adaptation and mitigation policies for the populations they serve.

Air Pollution and Climate Change Effects on Allergies in the Anthropocene: Abundance, Interaction, and Modification of Allergens and Adjuvants

Air pollution and climate change are potential drivers for the increasing burden of allergic diseases. The molecular mechanisms by which air pollutants and climate parameters may influence allergic diseases, however, are complex and elusive. This article provides an overview of physical, chemical and biological interactions between air pollution, climate change, allergens, adjuvants and the immune system, addressing how these interactions may promote the development of allergies. We reviewed and synthesized key findings from atmospheric, climate, and biomedical research. The current state of knowledge, open questions, and future research perspectives are outlined and discussed. The Anthropocene, as the present era of globally pervasive anthropogenic influence on planet Earth and, thus, on the human environment, is characterized by a strong increase of carbon dioxide, ozone, nitrogen oxides, and combustion- or traffic-related particulate matter in the atmosphere. These environmental factors can enhance the abundance and induce chemical modifications of allergens, increase oxidative stress in the human body, and skew the immune system toward allergic reactions. In particular, air pollutants can act as adjuvants and alter the immunogenicity of allergenic proteins, while climate change affects the atmospheric abundance and human exposure to bioaerosols and aeroallergens. To fully understand and effectively mitigate the adverse effects of air pollution and climate change on allergic diseases, several challenges remain to be resolved. Among these are the identification and quantification of immunochemical reaction pathways involving allergens and adjuvants under relevant environmental and physiological conditions.

Asthma as a disruption in iron homeostasis

Over several decades, asthma has evolved from being recognized as a single disease to include a diverse group of phenotypes with dissimilar natural histories, pathophysiologies, responses to treatment, and distinctive molecular pathways. With the application of Occam's razor to asthma, it is proposed that there is one cause underlying the numerous phenotypes of this disease and that the responsible molecular pathway is a deficiency of iron in the lung tissues. This deficiency can be either absolute (e.g. asthma in the neonate and during both pregnancy and menstruation) or functional (e.g. asthma associated with infections, smoking, and obesity). Comparable associations between asthma co-morbidity (e.g. eczema, urticaria, restless leg syndrome, and pulmonary hypertension) with iron deficiency support such a shared mechanistic pathway. Therapies directed at asthma demonstrate a capacity to impact iron homeostasis, further strengthening the relationship. Finally, pathophysiologic events producing asthma, including inflammation, increases in Th2 cells, and muscle contraction, can correlate with iron availability. Recognition of a potential association between asthma and an absolute and/or functional iron deficiency suggests specific therapeutic interventions including inhaled iron.

Weather elements, chemical air pollutants and airborne pollen influencing asthma emergency room visits in Szeged, Hungary: performance of two objective weather classifications

Weather classification approaches may be useful tools in modelling the occurrence of respiratory diseases. The aim of the study is to compare the performance of an objectively defined weather classification and the Spatial Synoptic Classification (SSC) in classifying emergency department (ED) visits for acute asthma depending from weather, air pollutants, and airborne pollen variables for Szeged, Hungary, for the 9-year period 1999-2007. The research is performed for three different pollen-related periods of the year and the annual data set. According to age and gender, nine patient categories, eight meteorological variables, seven chemical air pollutants, and two pollen categories were used. In general, partly dry and cold air and partly warm and humid air aggravate substantially the symptoms of asthmatics. Our major findings are consistent with this establishment. Namely, for the objectively defined weather types favourable conditions for asthma ER visits occur when an anticyclonic ridge weather situation happens with near extreme temperature and humidity parameters. Accordingly, the SSC weather types facilitate aggravating asthmatic conditions if warm or cool weather occur with high humidity in both cases. Favourable conditions for asthma attacks are confirmed in the extreme seasons when atmospheric stability contributes to enrichment of air pollutants. The total efficiency of the two classification approaches is similar in spite of the fact that the methodology for derivation of the individual types within the two classification approaches is completely different.

Impacts of travel activity and urbanicity on exposures to ambient oxides of nitrogen and on exposure disparities

Daily exposures to ambient oxides of nitrogen were estimated here for residents of Hillsborough County, FL. The 2009 National Household Travel Survey provided geocoded data on fixed activity locations during each person-day sampled. Routes between activity locations were calculated from transportation network data, assuming the quickest travel path. To estimate daily exposure concentrations for each person-day, the exposure locations were matched with diurnally and spatially varying ambient pollutant concentrations derived from CALPUFF dispersion model results. The social distribution of exposures was analyzed by comparing frequency distributions of grouped daily exposure concentrations and by regression modeling. To investigate exposure error, the activity-based exposure estimates were also compared with estimates derived using residence location alone. The mean daily activity-based exposure concentration for the study sample was 17 μg/m³, with values for individual person-day records ranging from 7.0 to 43 μg/m³. The highest mean exposure concentrations were found for the following groups: black (20 μg/m³), below poverty (18 μg/m³), and urban residence location (22 μg/m³). Urban versus rural residence was associated with the largest increase in exposure concentration in the regression (8.3 μg/m³). Time in nonresidential activities, including travel, was associated with an increase of 0.2 μg/m³ per hour. Time spent travelling and at nonresidential locations contributed an average of 6 and 24 %, respectively, to the daily estimate. A mean error of 3.6 %, with range from -64 to 58 %, was found to result from using residence location alone. Exposure error was highest for those who travel most, but lowest for the sociodemographic subgroups with higher mean exposure concentrations (including blacks and those from below poverty households). This work indicates the importance of urbanicity to social disparities in activity-based air pollution exposures. It also suggests that exposure error due to using residence location may be smaller for more exposed groups.

Quality of life in relation to the traffic pollution indicators NO2 and NOx: results from the Swedish GA(2)LEN survey

BACKGROUND

Asthma is a chronic disease that may affect daily activities and quality of life. Asthmatics have higher incidence of chronic rhinosinusitis (CRS) and asthma is associated with sinonasal inflammation and nasal symptoms, that all impair quality of life. Worsening of asthma has been found associated with levels of nitrogen dioxide as traffic indicator.

AIMS

The aim of the study was to evaluate the impact of traffic pollution indicated by nitrogen oxides (NO2 and NOx) on quality of life in asthmatic persons, individuals with CRS and controls.

METHODS

Within the Swedish Ga(2)len (Global Allergy and Asthma European Network), 605 asthmatics with and without CRS, 110 individuals with CRS only and 226 controls from four cities were surveyed. The mini Asthma Quality of life Questionnaire (mAQLQ) and the Euro Quality of Life (EQ-5D) health questionnaire were used. Air pollution concentrations at the home address were modelled using dispersion models.

RESULTS

Levels of NO2 (geometric mean 10.1 μg/m(3) (95% CI 9.80 to 10.5) and NOx (12.1 μg/m(3), 11.7 to 12.6) were similar among conditions (controls, asthmatics, individuals with CRS and asthmatics with CRS). The mAQLQ overall score was not found associated with levels of NO2 or NOx, with or without adjustments, and neither was scores within each of the four domains of mAQLQ: symptoms, activity limitations, emotional functions and effects of environmental stimuli. The mean EQ-5D index value, based on the five dimensions mobility, self-care, usual activities, pain/discomfort and anxiety depression, was also found unrelated to NO2 and NOx.

CONCLUSIONS

At moderate exposure levels traffic pollution appears not to affect quality of life.

Geospatial relationships of air pollution and acute asthma events across the Detroit-Windsor international border: study design and preliminary results

The Geospatial Determinants of Health Outcomes Consortium (GeoDHOC) study investigated ambient air quality across the international border between Detroit, Michigan, USA and Windsor, Ontario, Canada and its association with acute asthma events in 5- to 89-year-old residents of these cities. NO2, SO2, and volatile organic compounds (VOCs) were measured at 100 sites, and particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) at 50 sites during two 2-week sampling periods in 2008 and 2009. Acute asthma event rates across neighborhoods in each city were calculated using emergency room visits and hospitalizations and standardized to the overall age and gender distribution of the population in the two cities combined. Results demonstrate that intra-urban air quality variations are related to adverse respiratory events in both cities. Annual 2008 asthma rates exhibited statistically significant positive correlations with total VOCs and total benzene, toluene, ethylbenzene and xylene (BTEX) at 5-digit zip code scale spatial resolution in Detroit. In Windsor, NO2, VOCs, and PM10 concentrations correlated positively with 2008 asthma rates at a similar 3-digit postal forward sortation area scale. The study is limited by its coarse temporal resolution (comparing relatively short term air quality measurements to annual asthma health data) and interpretation of findings is complicated by contrasts in population demographics and health-care delivery systems in Detroit and Windsor.

Climate change. A global threat to cardiopulmonary health

Recent changes in the global climate system have resulted in excess mortality and morbidity, particularly among susceptible individuals with preexisting cardiopulmonary disease. These weather patterns are projected to continue and intensify as a result of rising CO2 levels, according to the most recent projections by climate scientists. In this Pulmonary Perspective, motivated by the American Thoracic Society Committees on Environmental Health Policy and International Health, we review the global human health consequences of projected changes in climate for which there is a high level of confidence and scientific evidence of health effects, with a focus on cardiopulmonary health. We discuss how many of the climate-related health effects will disproportionally affect people from economically disadvantaged parts of the world, who contribute relatively little to CO2 emissions. Last, we discuss the financial implications of climate change solutions from a public health perspective and argue for a harmonized approach to clean air and climate change policies.

Chronic traffic pollution exposure is associated with eosinophilic, but not neutrophilic inflammation in older adult asthmatics

OBJECTIVE

Airway inflammatory patterns in older asthmatics are poorly understood despite high asthma-related morbidity and mortality. In this study, we sought to define the relationship between exposure to traffic pollutants, biomarkers in induced sputum, and asthma control in older adults.

METHODS

Induced sputum was collected from 35 non-smoking adults ≥65 years with a physician's diagnosis of asthma and reversibility with a bronchodilator or a positive methacholine challenge. Patients completed the Asthma Control Questionnaire (ACQ), and Elemental Carbon Attributable to Traffic (ECAT), a surrogate for chronic diesel particulate exposure, was determined. Equal numbers of subjects with high (≥0.39 µg/m(3)) versus low (<0.39 µg/m(3)) ECAT were included. Differential cell counts were performed on induced sputum, and myeloperoxidase (MPO) and eosinophil peroxidase (EPO) were measured in supernatants. Regression analyses were used to evaluate the relationship between sputum findings, ACQ scores, and ECAT.

RESULTS

After adjustment for potential confounders, subjects with poorly controlled asthma based on ACQ ≥ 1.5 (n = 7) had significantly higher sputum eosinophils (median = 4.4%) than those with ACQ < 1.5 (n = 28; eosinophils = 2.6%; β = 10.1 [95% CI = 0.1-21.0]; p = 0.05). Subjects with ACQ ≥ 1.5 also had significantly higher sputum neutrophils (84.2% versus 65.2%; β = 7.1 [0.2-14.6]; p = 0.05). Poorly controlled asthma was associated with higher sputum EPO (β = 2.4 [0.2-4.5], p = 0.04), but not MPO (p = 0.9). High ECAT was associated with higher eosinophils (β = 10.1 [1.8-18.4], p = 0.02) but not higher neutrophils (p = 0.6).

CONCLUSIONS

Poorly controlled asthma in older adults is associated with eosinophilic and neutrophilic inflammation. Chronic residential traffic pollution exposure may be associated with eosinophilic, but not neutrophilic inflammation in older asthmatics.

Lungs in a warming world: climate change and respiratory health

Climate change is a health threat no less consequential than cigarette smoking. Increased concentrations of greenhouse gases, and especially CO₂, in the earth's atmosphere have already warmed the planet substantially, causing more severe and prolonged heat waves, temperature variability, air pollution, forest fires, droughts, and floods, all of which put respiratory health at risk. These changes in climate and air quality substantially increase respiratory morbidity and mortality for patients with common chronic lung diseases such as asthma and COPD and other serious lung diseases. Physicians have a vital role in addressing climate change, just as they did with tobacco, by communicating how climate change is a serious, but remediable, hazard to their patients.

Air pollution and asthma control in the Epidemiological study on the Genetics and Environment of Asthma

BACKGROUND

The associations between exposure to air pollution and asthma control are not well known. The objective of this study was to assess the association between long-term exposure to NO(2), O(3) and PM(10) and asthma control in the follow-up of the Epidemiological study on the Genetics and Environment of Asthma (EGEA2) (2003-2007).

METHODS

Modelled outdoor NO(2), O(3) and PM(10) estimates were linked to each residential address using the 4 km grid air pollutant surface developed by the French Institute of Environment in 2004. Asthma control was assessed in 481 subjects with current asthma using a multidimensional approach following the 2006-2009 Global Initiative for Asthma guidelines. Multinomial and ordinal logistic regressions were conducted adjusted for sex, age, body mass index, education, smoking and use of inhaled corticosteroids. The association between air pollution and the three domains of asthma control (symptoms, exacerbations and lung function) was assessed. ORs are reported per IQR.

RESULTS

Median concentrations (in micrograms per cubic metre) were 32 (IQR 25-38) for NO(2) (n=465), 46 (41-52) for O(3) and 21 (18-21) for PM(10) (n=481). In total, 44%, 29% and 27% had controlled, partly controlled and uncontrolled asthma, respectively. The ordinal ORs for O(3) and PM(10) with asthma control were 1.69 (95% CI 1.22 to 2.34) and 1.35 (95% CI 1.13 to 1.64), respectively. When including both pollutants in the same model, both associations persisted. Associations were not modified by sex, smoking status, use of inhaled corticosteroids, atopy, season of examination or body mass index. Both pollutants were associated with each of the three main domains of control.

CONCLUSIONS

The results suggest that long-term exposure to PM(10) and O(3) is associated with uncontrolled asthma in adults, defined by symptoms, exacerbations and lung function.

Examining the representativeness of home outdoor PM(2.5), EC, and OC estimates for daily personal exposures in Southern California

Recent studies have linked acute respiratory and cardiovascular outcomes to measurements or estimates of traffic-related air pollutants at homes or schools. However, few studies have evaluated these outdoor measurements and estimates against personal exposure measurements. We compared measured and modeled home outdoor concentrations with personal measurements of traffic-related air pollutants in the Los Angeles air basin (Whittier and Riverside). Personal exposure of 63 children with asthma and 15 homes were assessed for particulate matter with an aerodynamic diameter less than 2.5 μm (PM(2.5)), elemental carbon (EC), and organic carbon (OC) during sixteen 10-day monitoring runs. Regression models to predict daily home outdoor PM(2.5), EC, and OC were constructed using home outdoor measurements, geographical and meteorological parameters, as well as CALINE4 estimates at outdoor home sites, which represent the concentrations from local traffic sources. These home outdoor models showed the variance explained (R(2)) was 0.97 and 0.94 for PM(2.5), 0.91 and 0.83 for OC, and 0.76 and 0.87 for EC in Riverside and Whittier, respectively. The PM(2.5) outdoor estimates correlated well with the personal measurements (Riverside R(2) = 0.65 and Whittier R(2) = 0.69). However, excluding potentially inaccurate samples from Riverside, the correlation between personal exposure to carbonaceous species and home outdoor estimates in Whittier was moderate for EC (R(2) = 0.37) and poor for OC (R(2) = 0.08). The CALINE4 estimates alone were not correlated with personal measurements of EC or other pollutants. While home outdoor estimates provide good approximations for daily personal PM(2.5) exposure, they may not be adequate for estimating daily personal exposure to EC and OC. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11869-010-0099-y) contains supplementary material, which is available to authorized users.

Association of allergic asthma emergency room visits with the main biological and chemical air pollutants

Joint effect of biological (pollen) and chemical air pollutants on asthma emergency room (ER) visits was analyzed for Szeged region of Southern Hungary. Our database of a nine-year period (1999-2007) includes daily number of asthma emergency room (ER) visits, and daily mean concentrations of CO, PM(10), NO, NO(2), O(3) and SO(2), furthermore two pollen variables (Ambrosia and total pollen excluding Ambrosia), as well. The analysis was performed for ER visits of asthma bronchiale using two age groups (adults and the elderly) of males and females for three seasons. Factor analysis was performed in order to clarify the relative importance of the pollutant variables affecting asthma ER visits. Asthma ER visits denote notably stronger associations with the pollutants in adult male than in adult female patients both for the pollen season of Ambrosia and the pollen-free season. Furthermore, adults are substantially more sensitive to severe asthma attack than the elderly for the season of total pollen excluding Ambrosia pollen. The joint effect of the chemical and pollen variables is the highest for the asthma ER cases in the pollen season of Ambrosia, basically due to the extra impact of the total pollen excluding Ambrosia pollen and partly due to Ambrosia pollen. A nonparametric regression technique was applied to discriminate between events of ER visit-no ER visit using pollen and chemical pollutants as explaining variables. Based on multiple correlations, the strongest relationships between ER visits and pollutants are observed during the pollen-free season. The elderly group with asthma bronchiale is characterized by weaker relationships between ER visits and pollutants compared to adults. Ratio of the number of correct decisions on the events of ER visit-no ER visit is lowest for the season of total pollen excluding Ambrosia pollen. Otherwise, similar conclusions hold as those received by multiple correlations.

[Health risk assessment of traffic-related air pollution near busy roads]

BACKGROUND

Although ambient urban air pollution has well-established health effects, epidemiology faces many difficulties in estimating the risks due to exposure to traffic pollutants near busy roads. This review aims to summarize how exposure to traffic-related air pollution near busy roads is assessed in epidemiological studies and main findings regarding health effects.

METHOD

After presenting the specificity of emissions due to traffic road, this review identifies the key methods and main results found in epidemiologic studies seeking to measure the influence of exposure to nearby traffic on health published over the past decade.

RESULTS

The characterization and measurement of population exposure to traffic pollution faces many difficulties. Thus, epidemiological studies have used two broad categories of surrogates to assess exposure: direct measures of traffic itself such as distance of the residence to the nearest road and traffic volume and modeled concentrations of pollutant surrogates. Studies that implemented these methods showed that people living near heavy traffic road or exposed to near-road air pollution tend to report more health outcomes.

DISCUSSION

Traffic-related air pollution near busy roads is the subject of increasing attention, and tends to be better characterized. However, its health impacts remain difficult to grasp, especially because of the vast diversity of approaches used in epidemiological studies. Greater consistency in the protocols would be desirable to provide better understanding of the health issue of traffic in urban areas and thus to better implement policies to protect those most at risk.

Poor asthma control and exposure to traffic pollutants and obesity in older adults

BACKGROUND

Environmental and host predictors of asthma control in older asthmatic patients (>65 years old) are poorly understood.

OBJECTIVE

To examine the effects of residential exposure to traffic exhaust and other environmental and host predictors on asthma control in older adults.

METHODS

One hundred four asthmatic patients 65 years of age or older from allergy and pulmonary clinics in greater Cincinnati, Ohio, completed the validated Asthma Control Questionnaire (ACQ), pulmonary function testing, and skin prick testing to 10 common aeroallergens. Patients had a physician's diagnosis of asthma, had significant reversibility in forced expiratory volume in 1 second or a positive methacholine challenge test result, and did not have chronic obstructive pulmonary disease. The mean daily residential exposure to elemental carbon attributable to traffic (ECAT) was estimated using a land-use regression model. Regression models were used to evaluate associations among independent variables, ACQ scores, and the number of asthma exacerbations, defined as acute worsening of asthma symptoms requiring prednisone use, in the past year.

RESULTS

In the adjusted model, mean daily residential exposure to ECAT greater than 0.39 μg/m(3) was significantly associated with poorer asthma control based on ACQ scores (adjusted β = 2.85; 95% confidence interval [CI], 0.58-5.12; P = .02). High ECAT levels were also significantly associated with increased risk of asthma exacerbations (adjusted odds ratio, 3.24; 95% CI, 1.01-10.37; P = .05). A significant association was found between higher body mass index and worse ACQ scores (adjusted β = 1.15; 95% CI, 0.53-1.76; P < .001). Atopic patients (skin prick test positive) had significantly better ACQ scores than nonatopic patients (adjusted β = -0.39; 95% CI, -0.67 to -0.11; P < .01).

CONCLUSION

Higher mean daily residential exposure to traffic exhaust, obesity, and nonatopic status are associated with poorer asthma control among older asthmatic patients.

Asthma in the elderly: Current understanding and future research needs--a report of a National Institute on Aging (NIA) workshop

Asthma in the elderly is underdiagnosed and undertreated, and there is a paucity of knowledge on the subject. The National Institute on Aging convened this workshop to identify what is known and what gaps in knowledge remain and suggest research directions needed to improve the understanding and care of asthma in the elderly. Asthma presenting at an advanced age often has similar clinical and physiologic consequences as seen with younger patients, but comorbid illnesses and the psychosocial effects of aging might affect the diagnosis, clinical presentation, and care of asthma in this population. At least 2 phenotypes exist among elderly patients with asthma; those with longstanding asthma have more severe airflow limitation and less complete reversibility than those with late-onset asthma. Many challenges exist in the recognition and treatment of asthma in the elderly. Furthermore, the pathophysiologic mechanisms of asthma in the elderly are likely to be different from those seen in young asthmatic patients, and these differences might influence the clinical course and outcomes of asthma in this population.

Tráfego veicular como método de avaliação da exposição à poluição atmosférica nas grandes metrópoles

A poluição atmosférica é uma das maiores preocupações para a saúde pública. Entre os estudos conduzidos para testar a associação entre poluição do ar e os mais diversos desfechos em saúde, alguns utilizaram dados viários e de tráfego veicular como avaliação da exposição. O presente trabalho pretende revisar e discutir alguns dos aspectos metodológicos dos estudos que utilizaram este método, principalmente em áreas onde a fonte veicular é uma grande geradora de poluentes. Realizou-se uma busca bibliográfica com palavras-chave relacionadas à poluição atmosférica e tráfego veicular, e foram selecionados artigos publicados entre os anos de 2000 e 2009. Foram constatadas várias abordagens para avaliar a exposição, enfatizando-se o método da Densidade de Tráfego Ponderada pela Distância, que considera as vias e a distância das mesmas em relação ao local de interesse e o tráfego. Além disso, destaca-se a importância do uso de técnicas de sistemas de informação geográfica (SIG) como instrumento na construção de modelos para mensurar a exposição.

Mechanism of asthmatic exacerbation by ambient air pollution particles

In the previous two to three decades, the prevalence of asthma has risen in numerous countries of the world. Correlating with this elevated prevalence of asthma, societies have observed increased air pollution from specific sources. Studies have implicated certain pollutants in asthmatic exacerbation. Particulate matter (PM) is the pollutant most frequently identified with worsening of this airway disease. PM is a temporally and spatially shifting suspension of solids and liquids originating from both natural and anthropogenic sources. Exposures to elevated levels of PM have been associated with asthmatic exacerbations by employing a diverse array of end points, including respiratory symptoms, use of medication, medical visits, emergency room visits, hospital admissions and pulmonary function decrements. Pertinent to worsening of asthma by ambient air PM, there are other particle-associated exposures that similarly precipitate asthmatic exacerbations. These include traffic-associated pollutants, diesel exhaust, emissions from gas and wood stoves, burning of biomass and environmental tobacco smoke. It is widely accepted that the biological effects exerted by all particle exposures result from oxidative stress. This stimulates cell signaling, transcription factor activation and mediator release in the respiratory tract, culminating in inflammation. Other postulated mechanisms for asthmatic exacerbation following PM exposure include an impact on the incidence of infections and adjuvant effects.

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

BACKGROUND

Individual home characteristics have been associated with indoor allergen exposure; however, the influence of neighborhood-level characteristics has not been well studied. We defined neighborhoods as community districts determined by the New York City Department of City Planning.

OBJECTIVE

We examined the relationship between neighborhood-level characteristics and the presence of dust mite (Der f 1), cat (Fel d 1), cockroach (Bla g 2), and mouse (MUP) allergens in the household.

METHODS

Using data from the Puerto Rican Asthma Project, a birth cohort of Puerto Rican children at risk of allergic sensitization (n = 261), we examined associations between neighborhood characteristics (percent tree canopy, asthma hospitalizations per 1,000 children, roadway length within 100 meters of buildings, serious housing code violations per 1000 rental units, poverty rates, and felony crime rates), and the presence of indoor allergens. Allergen cutpoints were used for categorical analyses and defined as follows: dust mite: >0.25 microg/g; cat: >1 microg/g; cockroach: >1 U/g; mouse: >1.6 microg/g.

RESULTS

Serious housing code violations were statistically significantly positively associated with dust mite, cat, and mouse allergens (continuous variables), adjusting for mother's income and education, and all neighborhood-level characteristics. In multivariable logistic regression analyses, medium levels of housing code violations were associated with higher dust mite and cat allergens (1.81, 95%CI: 1.08, 3.03 and 3.10, 95%CI: 1.22, 7.92, respectively). A high level of serious housing code violations was associated with higher mouse allergen (2.04, 95%CI: 1.15, 3.62). A medium level of housing code violations was associated with higher cockroach allergen (3.30, 95%CI: 1.11, 9.78).

CONCLUSIONS

Neighborhood-level characteristics, specifically housing code violations, appear to be related to indoor allergens, which may have implications for future research explorations and policy decisions.

Sensationalistic journalism and tales of snakebite: are rattlesnakes rapidly evolving more toxic venom?

Recent reports in the lay press have suggested that bites by rattlesnakes in the last several years have been more severe than those in the past. The explanation, often citing physicians, is that rattlesnakes are evolving more toxic venom, perhaps in response to anthropogenic causes. We suggest that other explanations are more parsimonious, including factors dependent on the snake and factors associated with the bite victim's response to envenomation. Although bites could become more severe from an increased proportion of bites from larger or more provoked snakes (ie, more venom injected), the venom itself evolves much too slowly to explain the severe symptoms occasionally seen. Increased snakebite severity could also result from a number of demographic changes in the victim profile, including age and body size, behavior toward the snake (provocation), anatomical site of bite, clothing, and general health including asthma prevalence and sensitivity to foreign antigens. Clinical management of bites also changes perpetually, rendering comparisons of snakebite severity over time tenuous. Clearly, careful study taking into consideration many factors will be essential to document temporal changes in snakebite severity or venom toxicity. Presently, no published evidence for these changes exists. The sensationalistic coverage of these atypical bites and accompanying speculation is highly misleading and can produce many detrimental results, such as inappropriate fear of the outdoors and snakes, and distraction from proven snakebite management needs, including a consistent supply of antivenom, adequate health care, and training. We urge healthcare providers to avoid propagating misinformation about snakes and snakebites.

Spatial modeling of PM10 and NO2 in the continental United States, 1985-2000

BACKGROUND

Epidemiologic studies of air pollution have demonstrated a link between long-term air pollution exposures and mortality. However, many have been limited to city-specific average pollution measures or spatial or land-use regression exposure models in small geographic areas.

OBJECTIVES

Our objective was to develop nationwide models of annual exposure to particulate matter < 10 microm in diameter (PM(10)) and nitrogen dioxide during 1985-2000.

METHODS

We used generalized additive models (GAMs) to predict annual levels of the pollutants using smooth spatial surfaces of available monitoring data and geographic information system-derived covariates. Model performance was determined using a cross-validation (CV) procedure with 10% of the data. We also compared the results of these models with a commonly used spatial interpolation, inverse distance weighting.

RESULTS

For PM(10), distance to road, elevation, proportion of low-intensity residential, high-intensity residential, and industrial, commercial, or transportation land use within 1 km were all statistically significant predictors of measured PM(10) (model R(2) = 0.49, CV R(2) = 0.55). Distance to road, population density, elevation, land use, and distance to and emissions of the nearest nitrogen oxides-emitting power plant were all statistically significant predictors of measured NO(2) (model R(2) = 0.88, CV R(2) = 0.90). The GAMs performed better overall than the inverse distance models, with higher CV R(2) and higher precision.

CONCLUSIONS

These models provide reasonably accurate and unbiased estimates of annual exposures for PM(10) and NO(2). This approach provides the spatial and temporal variability necessary to describe exposure in studies assessing the health effects of chronic air pollution.

The relationship of short-term air pollution and weather to ED visits for asthma in Japan

INTRODUCTION

The incidence of asthma exacerbation has been increasing in many countries. Environmental factors may play an important role in this trend. We aimed to investigate the relationship of weather conditions and air pollution to significant exacerbation of asthma.

METHODS

The daily number of emergency department (ED) visits by ambulance for asthma was collected through records of the Tokyo Fire Department from January 1 to December 31, 2005. We also collected daily air pollution levels and meteorological data for Tokyo during the same period. Meteorological data included minimum temperature, maximum barometric pressure, maximum relative humidity, and precipitation. Measured air pollutants included sulfur dioxide, nitrogen monoxide, nitrogen oxides, suspended particulate matter, and carbon monoxide. We performed a time series analysis using multivariable-adjusted autoregressive integrated moving average model. The analysis was conducted separately among adults and among children (<15 years old).

RESULTS

Of a total of 643,849 patients who were transported to the ED by ambulance, there were 6447 patients with exacerbation of asthma. Among adults, lower minimum temperature was significantly associated with increased transport. Among children, there were no significant associations between exacerbation of asthmas requiring emergency transport and air pollutants or meteorological factors. The highest number of transports was found on October 11, the day after the National Sports Day in Japan.

CONCLUSIONS

Cold temperature is related to an increased risk of significant exacerbation of asthma in adults. Air pollution does not seem to play a major role in significant exacerbation of asthma requiring ambulance transports to ED.

Temporal-spatial analysis of U.S.-Mexico border environmental fine and coarse PM air sample extract activity in human bronchial epithelial cells

Particulate matter less than 10 microm (PM10) has been shown to be associated with aggravation of asthma and respiratory and cardiopulmonary morbidity. There is also great interest in the potential health effects of PM2.5. Particulate matter (PM) varies in composition both spatially and temporally depending on the source, location and seasonal condition. El Paso County which lies in the Paso del Norte airshed is a unique location to study ambient air pollution due to three major points: the geological land formation, the relatively large population and the various sources of PM. In this study, dichotomous filters were collected from various sites in El Paso County every 7 days for a period of 1 year. The sampling sites were both distant and near border crossings, which are near heavily populated areas with high traffic volume. Fine (PM2.5) and Coarse (PM10-2.5) PM filter samples were extracted using dichloromethane and were assessed for biologic activity and polycyclic aromatic (PAH) content. Three sets of marker genes human BEAS2B bronchial epithelial cells were utilized to assess the effects of airborne PAHs on biologic activities associated with specific biological pathways associated with airway diseases. These pathways included in inflammatory cytokine production (IL-6, IL-8), oxidative stress (HMOX-1, NQO-1, ALDH3A1, AKR1C1), and aryl hydrocarbon receptor (AhR)-dependent signaling (CYP1A1). Results demonstrated interesting temporal and spatial patterns of gene induction for all pathways, particularly those associated with oxidative stress, and significant differences in the PAHs detected in the PM10-2.5 and PM2.5 fractions. Temporally, the greatest effects on gene induction were observed in winter months, which appeared to correlate with inversions that are common in the air basin. Spatially, the greatest gene expression increases were seen in extracts collected from the central most areas of El Paso which are also closest to highways and border crossings.

Exposure to traffic: lung function and health status in adults with asthma

BACKGROUND

Exposure to traffic has been associated with asthma outcomes in children, but its effect on asthma in adults has not been well studied.

OBJECTIVE

To test the hypothesis that lung function and health status are associated with traffic exposures.

METHODS

We measured FEV(1) % predicted, general health status using the Physical Component Scale of the 12-item Short Form (SF-12 PCS), and quality of life (QoL) using the Marks Asthma Quality of Life questionnaire in a cohort of adults with asthma or rhinitis (n = 176; 145 with asthma). We assessed exposures to traffic by geocoding subjects' residential addresses and assigning distance to roadways. Associations between distance to nearest roadway and distance to nearest major roadway and FEV(1) % predicted or SF-12 PCS were studied by using linear regression.

RESULTS

FEV(1) % predicted was positively associated with distance from both nearest roadway (P = .01) and nearest major roadway (P = .02). SF-12 PCS and QoL were not significantly associated with either traffic variable. Adjustment for income, smoking, and obesity did not substantively change the associations of the traffic variables with FEV(1) % predicted (P = .04 for nearest roadway and P = .02 for nearest major roadway) and did not cause associations with either SF-12 PCS or QoL to become significant.

CONCLUSIONS

Traffic exposure was associated with decreased lung function in adults with asthma.

A new focus on assessing and treating asthma control in the African-American community: a call to action

Asthma continues to be a highly prevalent disease characterized by significant morbidity, unnecessary mortality, and substantial cost to the health care system. After decades of increasing prevalence, the number of current asthmatics in recent years has plateaued at approximately 22 million people in the United States. An additional 10 million Americans have a past history of asthma that is not active. The burden of asthma is higher among African Americans than in any other racial or ethnic group in America. The African-American community continues to experience a disproportional increase in asthma prevalence, morbidity, and mortality. The educational initiatives stemming from the newly revised National Heart Lung and Blood Institute (NHLBI) guidelines provide the opportunity to address the increased burden of asthma in the African American community. These new guidelines, released in August 2007, focus on asthma control as the primary goal of therapy, routine monitoring of asthma control, and use of asthma control assessments to direct treatment. The present review discusses the following: I. The impact of health disparities on outcomes of African Americans with asthma, II. The barriers that prevent asthmatic patients from achieving optimal control, III. The unique factors that challenge practitioners and patients in achieving optimal asthma control in the African American Community, IV. The impact of good asthma control and the need for patients and clinicians to assess asthma control in with a standardized assessment tool, and V. Strategic initiatives and the role of the End The Attacks NOW program in improving outcomes for African American patients with asthma.

Gene-environment interactions in the development of complex disease phenotypes

The lack of knowledge about the earliest events in disease development is due to the multi-factorial nature of disease risk. This information gap is the consequence of the lack of appreciation for the fact that most diseases arise from the complex interactions between genes and the environment as a function of the age or stage of development of the individual. Whether an environmental exposure causes illness or not is dependent on the efficiency of the so-called “environmental response machinery” (i.e., the complex of metabolic pathways that can modulate response to environmental perturbations) that one has inherited. Thus, elucidating the causes of most chronic diseases will require an understanding of both the genetic and environmental contribution to their etiology. Unfortunately, the exploration of the relationship between genes and the environment has been hampered in the past by the limited knowledge of the human genome, and by the inclination of scientists to study disease development using experimental models that consider exposure to a single environmental agent. Rarely in the past were interactions between multiple genes or between genes and environmental agents considered in studies of human disease etiology. The most critical issue is how to relate exposure-disease association studies to pathways and mechanisms. To understand how genes and environmental factors interact to perturb biological pathways to cause injury or disease, scientists will need tools with the capacity to monitor the global expression of thousands of genes, proteins and metabolites simultaneously. The generation of such data in multiple species can be used to identify conserved and functionally significant genes and pathways involved in gene-environment interactions. Ultimately, it is this knowledge that will be used to guide agencies such as the U.S. Department of Health and Human Services in decisions regarding biomedical research funding and policy.

Environmental public health tracking of childhood asthma using California health interview survey, traffic, and outdoor air pollution data

BACKGROUND

Despite extensive evidence that air pollution affects childhood asthma, state-level and national-level tracking of asthma outcomes in relation to air pollution is limited.

OBJECTIVES

Our goals were to evaluate the feasibility of linking the 2001 California Health Interview Survey (CHIS), air monitoring, and traffic data; estimate associations between traffic density (TD) or outdoor air pollutant concentrations and childhood asthma morbidity; and evaluate the usefulness of such databases, linkages, and analyses to Environmental Public Health Tracking (EPHT).

METHODS

We estimated TD within 500 feet of residential cross-streets of respondents and annual average pollutant concentrations based on monitoring station measurements. We used logistic regression to examine associations with reported asthma symptoms and emergency department (ED) visits/hospitalizations.

RESULTS

Assignment of TD and air pollution exposures for cross-streets was successful for 82% of children with asthma in Los Angeles and San Diego, California, Counties. Children with asthma living in high ozone areas and areas with high concentrations of particulate matter < 10 microm in aerodynamic diameter experienced symptoms more frequently, and those living close to heavy traffic reported more ED visits/hospitalizations. The advantages of the CHIS for asthma EPHT include a large and representative sample, biennial data collection, and ascertainment of important socio-demographic and residential address information. Disadvantages are its cross-sectional design, reliance on parental reports of diagnoses and symptoms, and lack of information on some potential confounders.

CONCLUSIONS

Despite limitations, the CHIS provides a useful framework for examining air pollution and childhood asthma morbidity in support of EPHT, especially because later surveys address some noted gaps. We plan to employ CHIS 2003 and 2005 data and novel exposure assessment methods to re-examine the questions raised here.

Binge drinking, poor mental health, and adherence to treatment among California adults with asthma

Binge drinking and poor mental health may affect adherence to treatment for individuals with asthma. The purposes were to (a) examine the relationship of self-reported binge drinking and mental health to adherence to daily asthma control medications and (b) identify other demographic and health-related factors associated with asthma control medication adherence. Secondary analyses of 2003 adult California Health Interview Survey data were undertaken, and these analyses identified 3.2 million California adults who had been told by a physician they had asthma. Of these, approximately 1.7 million were symptomatic. Binge drinking significantly predicted medication nonadherence among California adults with symptomatic asthma (OR = .63, 95% CI = .45-.89), whereas poor mental health did not. Other predictors of nonadherence (odds ratios < 1, p < .05) included being overweight, younger age, having some college education, being a current smoker, and having no usual source of medical care. Predictors of adherence (odds ratios > 1, p < .05) were older age, more frequent asthma symptoms, more ER visits, more missed work days, being African American, and being a non-citizen. Intervention efforts could be directed toward improving medication adherence among adult asthma patients who engage in risky health behaviors such as binge drinking. Also at risk for medication nonadherence and therefore good targets for asthma control medication management interventions are adults who are overweight, younger (18-44 age range), have some college education, and no usual source of medical care.

Are frequent asthma symptoms among low-income individuals related to heavy traffic near homes, vulnerabilities, or both?

PURPOSE

To investigate whether frequent asthma symptoms (daily/weekly symptoms) can be attributed to traffic-related exposures, poverty, and/or vulnerabilities.

METHODS

Annual average daily vehicle traffic density (TD) within 500 feet of 2001 California Health Interview Survey respondents' residential cross streets was calculated. Logistic regression analyses were performed to evaluate the association between annual average TD and frequent asthma symptoms with income as a confounder and a modifier.

RESULTS

After adjustment for age, sex, and race/ethnicity, a 92% increase in frequent asthma symptoms was observed among those in high TD and a 50% increase among those in medium TD compared to those in low TD. Adjustment for poverty did not change these estimates, but individuals in poverty were twice more likely to experience frequent symptoms. Furthermore, delays in care, a poor/fair health status, current/previous smoking, overweight/obese, or unemployment showed independent associations with frequent asthma symptoms. Analyses stratified on income indicated greater estimated traffic effects for asthmatics in poverty, whereas the estimates for asthmatics above the poverty level moved closer toward the null.

CONCLUSIONS

Traffic-related exposures, poverty and vulnerabilities all increased the risk of frequent asthma symptoms. Those in poverty appeared to be more strongly affected by heavy traffic near their residences.

Recent evidence for adverse effects of residential proximity to traffic sources on asthma

PURPOSE OF REVIEW

A growing body of evidence indicates that residential proximity to traffic sources increases the risk for asthma and asthma exacerbations. In this review we have considered publications from 2006-2007 that examined the impact of residential traffic-related exposures on asthma occurrence and severity.

RECENT FINDINGS

In these studies, exposures were estimated using traffic metrics based on residential distances from major roads and freeways, traffic densities around homes, and models of traffic exposure. Overall, residential proximity to traffic sources was associated with increased asthma occurrence and exacerbations in both children and adults. Land-use regression models were superior to individual traffic metrics in explaining the variability of traffic-related pollutants. Susceptibility may also play a role in variation in the effects of traffic on asthma.

SUMMARY

There is consistent evidence that living near traffic sources is associated with asthma occurrence and exacerbations. Future studies have the opportunity to improve exposure estimates by measuring traffic-related pollutants near homes and schools and including time/activity patterns in prediction models. Further research is also warranted to investigate the differential impact of traffic by genetic and other susceptibility factors and to identify specific pollutants that underlie the adverse effect of traffic on asthma.

Ozone, oxidant defense genes, and risk of asthma during adolescence

RATIONALE

Although oxidative stress is a cardinal feature of asthma, the roles of oxidant air pollutants and antioxidant genes heme oxygenase 1 (HMOX-1), catalase (CAT), and manganese superoxide dismutase (MNSOD) in asthma pathogenesis have yet to be determined.

OBJECTIVES

We hypothesized that the functional polymorphisms of HMOX-1 ([GT](n) repeat), CAT (-262C>T -844C>T), and MNSOD (Ala-9Val) are associated with new-onset asthma, and the effects of these variants vary by exposure to ozone, a potent oxidant air pollutant.

METHODS

We assessed this hypothesis in a population-based cohort of non-Hispanic (n = 1,125) and Hispanic white (n = 586) children who resided in 12 California communities and who were followed annually for 8 years to ascertain new-onset asthma.

MEASUREMENTS AND MAIN RESULTS

Air pollutants were continuously measured in each of the study communities during the 8 years of study follow-up. HMOX-1 "short" alleles (<23 repeats) were associated with a reduced risk for new-onset asthma among non-Hispanic whites (hazard ratio [HR], 0.64; 95% confidence interval [CI], 0.41-0.99). This protective effect was largest in children residing in low-ozone communities (HR, 0.48; 95% CI, 0.25-0.91) (interaction P value = 0.003). Little evidence for an association with HMOX-1 was observed among Hispanic children. In contrast, Hispanic children with a variant of the CAT-262 "T" allele (CT or TT) had an increased risk for asthma (HR, 1.78; P value = 0.01). The effects of these polymorphisms were not modified by personal smoking or secondhand-smoke exposure.

CONCLUSIONS

Functional promoter variants in CAT and HMOX-1 showed ethnicity-specific associations with new-onset asthma. Oxidant gene protection was restricted to children living in low-ozone communities.