Association between Air Pollutants and Asthma Emergency Room Visits and Hospital Admissions in Time Series Studies: A Systematic Review and Meta-Analysis

Short-term impact of PM2.5 on contemporaneous asthma medication use: Behavior and the value of pollution reductions

Asthma ranks among the most costly of chronic diseases, accounting for over $50 billion annually in direct medical expenditures in the United States. At the same time, evidence has accumulated that fine particulate matter pollution can exacerbate asthma symptoms and generate substantial economic costs. To measure these costs, we use a unique nationwide panel dataset tracking asthmatic individuals' use of rescue medication and their exposure to PM2.5 (particulate matter with an aerodynamic diameter of <2.5 μm) concentration between 2012 and 2017, to estimate the causal relationship between pollution and inhaler use. Our sample consists of individuals using an asthma digital health platform, which relies on a wireless sensor to track the place and time of inhaler use events, as well as regular nonevent location and time indicators. These data provide an accurate measurement of inhaler use and allow spatially and temporally resolute assignment of pollution exposure. Using a high-frequency research design and individual fixed effects, we find that a 1 μg/m3 (12%) increase in weekly exposure to PM2.5 increases weekly inhaler use by 0.82%. We also show that there is seasonal, regional, and income-based heterogeneity in this response. Using our response prediction, and an estimate from the literature on the willingness to pay to avoid asthma symptoms, we show that a nationwide 1 μg/m3 reduction in particulate matter concentration would generate nearly $350 million annually in economic benefits.

Longitudinal trends in asthma emergency department visits, pollutant and pollen levels, and weather variables in the Bronx from 2001-2008

Objective: To evaluate how asthma-related emergency department visits (AREDV), air pollutant levels, pollen counts, and weather variables changed from 2001 to 2008 in the Bronx, NY. Methods: 42,065 daily AREDV values (1 January 2001 to 31 December 2008) were collected using our institution's Clinical Looking Glass software. Daily values of sulfur dioxide (SO₂), carbon monoxide (CO), ozone (O₃), nitrogen dioxide (NO₂), temperature, and humidity were obtained from the National Climatic Data Center's Bronx station. Daily tree pollen counts were obtained from the Armonk counting station near the Bronx. Median values for each variable were analyzed using the Mann-Whitney test to compare 2001-2004 and 2005-2008 values. Simple linear regression examined associations between AREDV and individual pollutants. Due to seasonal variations of the variables, each season was considered separately. Results: There were significant decreases for AREDV, SO₂, CO, and humidity for all seasons, and for NO₂ in the spring and winter. Significant increases occurred for O₃ in the spring, fall, and winter; for temperature in the summer and winter; and for tree pollen in the spring. Significant positive associations were found between AREDV and SO₂, CO, NO₂, and humidity, respectively, while significant negative associations were found between AREDV and O₃ and temperature, respectively. Conclusions: From 2001 to 2008, significant: a) decreases in AREDV, SO₂, CO, and humidity for all seasons, and decreases in NO₂ for the spring and winter; and b) increases in O₃, temperature, and spring tree pollen were observed. By tracking and anticipating environmental and pollutant changes, efforts can be made to minimize AREDV.

Analysis of the effect of PM10 on hand, foot and mouth disease in a basin terrain city

Hand, foot, and mouth disease (HFMD) is a common childhood infection that causes a substantial disease burden in the Asia-Pacific region. Various climate variables, such as humidity and temperature, have been associated with HFMD. However, few studies have assessed the impact of PM₁₀ on childhood HFMD. This study investigated the association between PM₁₀ and HFMD. We fitted a standard distributed lag non-linear model to investigate the temporal lagged relationship between PM₁₀ and HFMD, and then further assessed whether this relationship varied by gender and pathogen. Between 2011 and 2015, a total of 122,564 HFMD cases under 15 years of age were reported in Chengdu. The PM₁₀-HFMD associations were shown to be non-linear in all subgroups, with the peak at 101–218 μg/m³. Male children were more sensitive to PM₁₀ effects. For pathogen-specific relative risks, we found that the risk estimates were generally higher in cases of CVA16 infection. Our study provides evidence that PM₁₀ increases the risk of HFMD. Authorities and parents should be fully aware of the impact of PM₁₀ on childhood HFMD. Furthermore, appropriate protective measures should be taken to reduce risks.

Diesel exhausts particles: Their role in increasing the incidence of asthma. Reviewing the evidence of a causal link

Exposure to air pollutants has been correlated with an increase in the severity of asthma and in the exacerbation of pre-existing asthma. However, whether or not environmental pollution can cause asthma remains a controversial issue. The present review analyzes the current scientific evidence of the possible causal link between diesel exhaust particles (DEP), the solid fraction of the complex mixture of diesel exhaust, and asthma. The mechanisms that influence the expression and development of asthma are complex. In children prolonged exposure to pollutants such as DEPs may increase asthma prevalence. In adults, this causal relation is less clear, probably because of the heterogeneity of the studies carried out. There is also evidence of physiological mechanisms by which DEPs can cause asthma. The most frequently described interactions between cellular responses and DEP are the induction of pulmonary oxidative stress and inflammation and the activation of receptors of the bronchial epithelium such as toll-like receptors or increases in Th2 and Th17 cytokines, which generally orchestrate the asthmatic response. Others support indirect mechanisms through epigenetic changes, pulmonary microbiome modifications, or the interaction of DEP with environmental antigens to enhance their activity. However, in spite of this evidence, more studies are needed to assess the harmful effects of pollution - not only in the short term in the form of increases in the rate of exacerbations, but in the medium and long term as well, as a possible trigger of the disease.

Effects of ambient air pollution on daily hospital admissions for respiratory and cardiovascular diseases in Bangkok, Thailand

BACKGROUND

Although health effects of air pollutants are well documented in many countries especially in North America and Western Europe, few studies have been conducted in Thailand where pollution mix, weather conditions, and demographic characteristics are different. The present study aimed to investigate the effects of ambient air pollution on hospital admissions for cardiovascular and respiratory diseases in Bangkok, Thailand.

METHODS

We obtained daily air pollution concentration (O₃, NO₂, SO₂, PM₁₀, and CO) and weather variable monitored in Bangkok from January 2006 to December 2014. Daily hospital admissions for cardiovascular and respiratory diseases were obtained from the National Health Security Office during the study period. A time-series analysis with generalized linear model was used to examine the effects of air pollution on hospital admissions by controlling for long-term trend and other potential confounders. The effect modification by age (0-14 years, 15-64 years, ≥65 years) and gender was also examined.

RESULTS

An increase of 10 μg/m³ in O₃, NO₂, SO₂, PM₁₀, and 1 mg/m³ in CO at lag 0-1 day was associated with a 0.14% (95% CI: -0.34 to 0.63), 1.28% (0.87 to 1.69), 8.42% (6.16 to 10.74), 1.04% (0.68 to 1.41) and 6.69% (4.33 to 9.11) increase in cardiovascular admission, respectively; and 0.69% (95% CI: 0.18 to 1.21), 1.42% (0.98 to 1.85), 4.49% (2.22 to 6.80), 1.18% (0.79 to 1.57) and 7.69% (5.20 to 10.23) increase in respiratory admission, respectively. The elderly (≥65 years) seemed to be the most susceptible group to the effect of air pollution, whereas the effect estimate for male and female was not significantly different.

CONCLUSIONS

Results from this study contributed the evidence to support the effects of air pollution (O₃, NO₂, SO₂, PM₁₀, and CO) on hospital admissions for cardiovascular and respiratory diseases, which might be useful for public health intervention in Thailand.

The short-term association between air pollution and childhood asthma hospital admissions in urban areas of Hefei City in China: A time-series study

BACKGROUND

The impacts of air pollution on asthma attacks have become a hotspot. Previous studies mainly focused on the developed countries or cities. There have been very limited studies in less-developed region to quantify the effects of air pollutants on asthma admissions in children. This study aims to assess the short-term impact of air pollutants on asthma hospital admissions for children in Hefei, China.

METHODS

Poisson generalized linear regression combined with distributed lag non-linear model (DLNM) were applied to investigate the effects of air pollutants on daily childhood hospital admissions of asthma from 2015 to 2016, controlling for meteorological factors. Subgroup analyses by sex and age were performed.

RESULTS

There were a total of 17,227 asthma admissions during 2015-2016. We found positive correlations between childhood asthma hospital visits and concentrations of NO₂, O₃, PM₁₀ and PM_2.5. Significantly, NO₂ exhibited robust positive correlations with cumulative effects 1.551 (95% CI: 1.306-1.841, lag0-3 days) in single-pollutant model and 1.580 (95% CI: 1.315-1.899, lag0-3 days) in multiple-pollutant model.

CONCLUSIONS

Air pollutants had adverse effects on childhood asthma. NO₂ presented the greatest effect, followed by PM_2.5. Results will be important for health authority and guardians to realize the severity of air pollution on the increased risk of asthma, so as to develop relevant strategies and health interventions to meet the challenges of childhood asthma and reduce air pollution.

The Short-Term Effects of Ambient Air Pollutants on Childhood Asthma Hospitalization in Taiwan: A National Study

This investigation determined the effects of air pollution on childhood asthma hospitalization in regions with differing air pollution levels in Taiwan over a long time period. Data of childhood hospital admissions for asthma in patients aged 0–18 years and air quality in eight regions for the period 2001–2012 in Taiwan were collected. Poisson generalized linear regression analysis was employed to identify the relative risks of hospitalization due to asthma in children associated with exposure to varying levels of air pollutants with a change in the interquartile range after adjusting for temperature and relative humidity. Particulate matter ≤2.5 μm (PM_2.5), particulate matter ≤10 μm (PM₁₀), ozone (O₃), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂), were positively associated with childhood asthma hospitalization, while O₃ was negatively associated with childhood asthma hospitalization. SO₂ was identified as the most significant risk factor. The relative risks for asthma hospitalization associated with air pollutants were higher among children aged 0–5 years than aged 6–18 years and were higher among males than females. The effects of air pollution on childhood asthma were greater in the higher-level air pollution regions, while no association was observed in the lower-level air pollution regions. These findings may prove important for policymakers involved in implementing policies to reduce air pollution.

Long-term exposure to ambient fine particles associated with asthma: A cross-sectional study among older adults in six low- and middle-income countries

BACKGROUND

Ambient PM_2.5 is considered harmful to the respiratory system. However, little has been shown about the long-term association between ambient PM_2.5 and asthma.

METHODS

A survey from 2007 to 2010 was conducted among adults over 50 years of age in six low- and middle- income countries (including China, India, Ghana, Mexico, Russia, and South Africa), which belonged to one part of a prospective cohort study - the Study on global AGEing and adult health. The yearly mean PM_2.5 concentrations of the residential communities of participants were estimated from remote sensing data. A mixed effects model was applied to investigate the association between ambient PM_2.5 and asthma.

RESULTS

A total of 4553 asthma patients were identified among the 29,249 participants in this study, producing a prevalence of 15.57%. For each 10 μg/m³ increase in PM_2.5, the adjusted prevalence ratio of asthma was 1.05 (95% Confidence Interval: 1.01, 1.08) after controlling for the effects of sex, age, BMI, education attainment, smoking status, alcohol consumption, and occupational exposure. Further analyses showed that males and smokers might be particularly vulnerable populations. Additionally, it was estimated that about 5.12% of the asthma cases in the study population (95% Confidence Interval: 1.44%, 9.23%) could be attributed to long-term PM_2.5 exposure.

CONCLUSION

Long-term exposure to PM_2.5 might be an important risk factor of asthma. Effective air pollution reduction measures should be taken to reduce PM_2.5 concentrations in order to reduce the associated asthma cases and disease burden.

Sulforaphane ameliorates steroid insensitivity through an Nrf2-dependent pathway in cigarette smoke-exposed asthmatic mice

Oxidative stress induced by cigarette smoke and other environmental pollutants contributes to refractory asthma. To better understand the role of smoking in asthma, we investigated the effects of cigarette smoke on allergic airway responses in mice and examined expression of nuclear factor-E2-related factor-2 (Nrf2) and its downstream factors, because Nrf2 is known to play a pivotal role in antioxidant responses. OVA-sensitized and challenged BALB/c mice were exposed to cigarette smoke and then treated with dexamethasone, sulforaphane (an activator of Nrf2), or their combination. Upon exposure to cigarette smoke, Nrf2 and associated transcripts were upregulated in response to oxidative stress, and asthmatic responses were steroid resistant. In OVA-sensitized and challenged mice exposed to cigarette smoke and treated with sulforaphane, Nrf2-mediated antioxidant responses were upregulated to a greater extent, and steroid sensitivity of asthmatic responses was restored. Moreover, the expression and activity of histone deacetylase 2 (HDAC2), a key regulator of steroid responsiveness, was reduced in mice exposed to cigarette smoke, but restored by sulforaphane treatment. No effects of sulforaphane were observed in Nrf2-deficient mice. These findings indicate that cigarette smoke induces steroid unresponsiveness in asthmatic airways, and that sulforaphane restores steroid sensitivity via upregulation of Nrf2 and enhancement of HDAC2 expression and activity. Thus, Nrf2 may serve as a potential molecular target for cigarette smoke-related refractory asthma resistant to steroid therapy.

Diagnosis and Treatment of Asthma in Nonpregnant Women

Asthma is a common condition affecting 8.3% of the adult population in the United States. The disease is characterized by chronic airway inflammation that leads to airway hyperresponsiveness and obstruction that results in coughing, wheezing, shortness of breath, and a feeling of chest tightness. The diagnosis and classification of asthma is based on reported symptoms, physical examination findings, and spirometry. Pharmacologic therapy is prescribed using a stepwise approach that begins with inhaled short-acting beta₂ -agonists for intermittent asthma with the addition of daily inhaled corticosteroids for more persistent cases. Individuals with asthma are reevaluated on a regular basis to monitor symptoms, and pharmacologic treatments are adjusted as needed. Familiarity with the stepwise approach for asthma management and confidence in the efficacy and safety profiles of inhaled medications will assist clinicians in successful management of asthma in the primary care setting.

Conurbation, Urban, and Rural Living as Determinants of Allergies and Infectious Diseases: Royal College of General Practitioners Research and Surveillance Centre Annual Report 2016-2017

BACKGROUND

Living in a conurbation, urban, or rural environment is an important determinant of health. For example, conurbation and rural living is associated with increased respiratory and allergic conditions, whereas a farm or rural upbringing has been shown to be a protective factor against this.

OBJECTIVE

The objective of the study was to assess differences in general practice presentations of allergic and infectious disease in those exposed to conurbation or urban living compared with rural environments.

METHODS

The population was a nationally representative sample of 175 English general practices covering a population of over 1.6 million patients registered with sentinel network general practices. General practice presentation rates per 100,000 population were reported for allergic rhinitis, asthma, and infectious conditions grouped into upper and lower respiratory tract infections, urinary tract infection, and acute gastroenteritis by the UK Office for National Statistics urban-rural category. We used multivariate logistic regression adjusting for age, sex, ethnicity, deprivation, comorbidities, and smoking status, reporting odds ratios (ORs) with 95% CIs.

RESULTS

For allergic rhinitis, the OR was 1.13 (95% CI 1.04-1.23; P=.003) for urban and 1.29 (95% CI 1.19-1.41; P<.001) for conurbation compared with rural dwellers. Conurbation living was associated with a lower OR for both asthma (OR 0.70, 95% CI 0.67-0.73; P<.001) and lower respiratory tract infections (OR 0.94, 95% CI 0.90-0.98; P=.005). Compared with rural dwellers, the OR for upper respiratory tract infection was greater in urban (OR 1.06, 95% CI 1.03-1.08; P<.001) but no different in conurbation dwellers (OR 1.00, 95% CI 0.97-1.03; P=.93). Acute gastroenteritis followed the same pattern: the OR was 1.13 (95% CI 1.01-1.25; P=.03) for urban dwellers and 1.04 (95% CI 0.93-1.17; P=.46) for conurbation dwellers. The OR for urinary tract infection was lower for urban dwellers (OR 0.94, 95% CI 0.89-0.99; P=.02) but higher in conurbation dwellers (OR 1.06, 95% CI 1.00-1.13; P=.04).

CONCLUSIONS

Those living in conurbations or urban areas were more likely to consult a general practice for allergic rhinitis and upper respiratory tract infection. Both conurbation and rural living were associated with an increased risk of urinary tract infection. Living in rural areas was associated with an increased risk of asthma and lower respiratory tract infections. The data suggest that living environment may affect rates of consultations for certain conditions. Longitudinal analyses of these data would be useful in providing insights into important determinants.

Effects of Migration on Allergic Diseases

Studies in migrant populations provide vital opportunities to investigate the role of environmental factors in the pathogenesis of allergic disorders. Differences in allergy prevalence have been observed between migrants and native-born subjects living in the same geographical location. Immigrants who migrate from less affluent countries with lower allergy prevalence tend to have a lower prevalence of allergic disorders compared to native-born residents of the more affluent host country. The patterns of allergic disease prevalence also differ between first- and second-generation migrants. The timing of migration in relation to birth, age at migration, and duration of residence in the host country also influence one's atopic risk. A complex interplay of multiple environmental, socioeconomic, and cultural factors is likely responsible for these observed differences. Further research into the roles of various risk factors in modulating differences in allergic disease prevalence between migrant and native populations will enhance our understanding of the complex gene-environment interactions involved in the pathogenesis of allergic disorders.

Particulate matter and childhood allergic diseases

Particulate matter (PM) is a ubiquitous air pollutant that is a growing public health concern. Previous studies have suggested that PM is associated with asthma development and exacerbation of asthma symptoms. Although several studies have suggested increased risks of atopic dermatitis, allergic rhinitis, and allergic sensitization in relation to PM exposure, the evidence remains inconsistent. The plausible mechanisms underlying these effects are related to oxidative stress, enhancement of sensitization to allergens, inflammatory and immunological responses, and epigenetics. This review discusses the effect of PM on childhood allergic diseases, along with plausible mechanisms. Further studies are required to understand the role of PM exposure on childhood allergic diseases, to reduce these diseases in children.

[Impact of the Air Quality on Health - Analysis of the activity of a SAMU-Center 15 in Paris area - the IQUASS Study]

INTRODUCTION

The atmospheric pollution is a growing public health problem. The highly urbanized regions such as Paris area seem particularly exposed. However, the overall health impact is poorly documented.

OBJECTIVE

To investigate the influence of air quality degradation on the demand for primary care.

METHOD

Site: medical dispatching center SAMU 93-Center 15. Related population: 1.6 million inhabitants.

DATA

daily number of medical regulation records (DRM) and daily air quality index (AQI) using the Airparif^® database from January 2014 to February 2017. The AQI is classified into five levels. Level 4 corresponds to the threshold of information and recommendations to reduce certain sources of polluting emissions and level 5 to the alert threshold setting up measures of restriction or suspension of the activities contributing to the pollution including vehicles circulation.

RESULTS

The analysis covered 1134 consecutive days and a total of 639,576 DRM. Average daily DRM number: 564 (507-643). IQA≥4 for 56 (5%) days and≥5 for 4 (0.4%) days. The number of DRM was very closely correlated with the IQA (R²=0.91); the daily median varied from 502 (494-621) for an IQA of level 1 to 650 (540-704) for an IQA≥4.

CONCLUSION

Degradation of air quality was significantly correlated with demand for primary care. The environmental alert is also a health alert. The impact was major (DRM +30%) considering all pathologies, all the pollutants on a departmental scale.

Effect of Air Pollution and Hospital Admission: A Systematic Review

IntroductionMany epidemiological studies have demonstrated associations between air pollution levels and human health in terms of hospital admissions. The aim of this paper is to gather evidence concerning air pollution effects on the risk of hospital admission. We hypothesised that increase in: particulate matter (PM), ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), and sulphur dioxide (SO2) levels would be associated with the increasing trend of hospital admission.MethodsA systematic review of literature was carried out. Literature search was done in Sage, Ovid Medline, Science Direct, Wiley and ProQuest from 2010 to 2016 using keywords "hospital admission and air pollution". Studies of any relevant design were included if they presented original data, included at least one analysis where hospital admission was the specific outcome, and one or more of the following exposures were investigated: PM, O3, CO, NO2 and SO2.ResultsA total of 175 potential studies were identified by the search. Twenty two studies qualified for the review. Air pollution was noted to have an excessive risk of 3.46 (95%CI, 1.67, 5.27) of total hospital admissions. Cardiovascular admission was noted to have an increased risk of hospitalization for PM2.5 of 1.5 to 2.0; PM10 (1.007 to 2.7); NO2 (1.04 to 1.17) and SO2 (1.007). For respiratory admission, PM2.5 can caused an increased risk of hospitalization by 1.1 to 1.8; PM10 (1.007 to 1.13); NO2 (1.08 to 1.94) and SO2 (1.02). While O3 have minimal effect on COPD and stroke, CO does not influence in the effect of these hospitalization.ConclusionThe exposure to air pollutants confers an increased risk of admission of several disease. Our findings call for greater awareness of environmental protection and the implementation of effective measures to improve the quality of air, which may reduce the risks of adverse effects on the population's health.

Effect of Air Pollution and Hospital Admission: A Systematic Review

Introduction:

Many epidemiological studies have demonstrated associations between air pollution levels and human health in terms of hospital admissions. The aim of this paper is to gather evidence concerning air pollution effects on the risk of hospital admission. We hypothesised that increase in: particulate matter (PM), ozone (O₃), carbon monoxide (CO), nitrogen dioxide (NO₂), and sulphur dioxide (SO₂) levels would be associated with the increasing trend of hospital admission.

Methods:

A systematic review of literature was carried out. Literature search was done in Sage, Ovid Medline, Science Direct, Wiley, and ProQuest from 2010 to 2016 using keywords “hospital admission and air pollution”. Studies of any relevant design were included if they presented original data, included at least one analysis where hospital admission was the specific outcome, and one or more of the following exposures were investigated: PM, O₃, CO, NO₂ and SO₂.

Results:

A total of 175 potential studies were identified by the search. Twenty-two studies qualified for the review. Air pollution was noted to have an excessive risk of 3.46 (95% CI, 1.67, 5.27) of total hospital admissions. Cardiovascular admission was noted to have an increased risk of hospitalization for PM_2.5 of 1.5 to 2.0; PM₁₀ (1.007 to 2.7); NO₂ (1.04 to 1.17) and SO₂ (1.007). For respiratory admission, PM_2.5 can caused an increased risk of hospitalization by 1.1 to 1.8; PM₁₀ (1.007 to 1.13); NO₂ (1.08 to 1.94) and SO₂ (1.02). While O₃ have minimal effect on COPD and stroke, CO does not influence in the effect of these hospitalization.

Conclusion:

The exposure to air pollutants confers an increased risk of admission of several disease. Our findings call for greater awareness of environmental protection and the implementation of effective measures to improve the quality of air, which may reduce the risks of adverse effects on the population’s health.

The association between pollutant levels and asthma-related emergency department visits in the Bronx after the World Trade Center attacks

Objective: To examine the potential impact of the World Trade Center (WTC) attacks on asthma-related emergency department visits (AREDV) in the New York City borough of the Bronx. Methods: We obtained daily nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and ozone (O₃) values from the National Climatic Data Center's collection station in the Bronx from 1999 and 2002, a year before and after the WTC attacks. We compared daily AREDV and pollutant levels between 1999 and 2002 using the Wilcoxon signed rank sum test. We considered each season separately due to seasonal variations of AREDV and pollutants. We then used multiple linear regression models to assess the relationships between the changes in AREDV and the changes in pollutants from 1999 to 2002 in each season. Results: There were statistically significant increases from 1999 to 2002 in the daily NO₂ in the summer. Significant increases for daily SO₂ and O₃ values from 1999 to 2002 occurred in all seasons. Significant increases occurred in daily AREDV values in the spring and fall. Multiple linear regression analyses showed that increases in the daily O₃ values were significantly associated with increases in AREDV from 1999 to 2002 in the summer season. Conclusion: We observed a possible association between the WTC attacks and significant increases in O₃ and SO₂ for all seasons, and NO₂ for the summer. AREDV significantly increased following the WTC attacks. Increases in daily O₃ values were significantly associated with increases in AREDV in the summer season.

The association between short and long-term exposure to PM2.5 and temperature and hospital admissions in New England and the synergistic effect of the short-term exposures

BACKGROUND

Particulate matter < 2.5 μm in diameter (PM2.5) and heat are strong predictors of morbidity, yet few studies have examined the effects of long-term exposures on non-fatal events, or assessed the short and long-term effect on health simultaneously.

OBJECTIVE

We jointly investigated the association of short and long-term exposures to PM2.5 and temperature with hospital admissions, and explored the modification of the associations with the short-term exposures by one another and by temperature variability.

METHODS

Daily ZIP code counts of respiratory, cardiac and stroke admissions of adults ≥65 (N = 2,015,660) were constructed across New-England (2001-2011). Daily PM2.5 and temperature exposure estimates were obtained from satellite-based spatio-temporally resolved models. For each admission cause, a Poisson regression was fit on short and long-term exposures, with a random intercept for ZIP code. Modifications of the short-term effects were tested by adding interaction terms with temperature, PM2.5 and temperature variability.

RESULTS

Associations between short and long-term exposures were observed for all of the outcomes, with stronger effects of long-term exposures to PM2.5. For respiratory admissions, the short-term PM2.5 effect (percent increase per IQR) was larger on warmer days (1.12% versus -0.53%) and in months of higher temperature variability (1.63% versus -0.45%). The short-term temperature effect was higher in months of higher temperature variability as well. For cardiac admissions, the PM2.5 effect was larger on colder days (0.56% versus -0.30%) and in months of higher temperature variability (0.99% versus -0.56%).

CONCLUSIONS

We observed synergistic effects of short-term exposures to PM2.5, temperature and temperature variability. Long-term exposures to PM2.5 were associated with larger effects compared to short-term exposures.

Trends in the Prevalence of Childhood Asthma in Seoul Metropolitan City, Korea: The Seoul Atopy ∙ Asthma-friendly School Project

Objectives

The project Seoul Atopy ∙ Asthma-friendly School investigated the current status of childhood asthma to enable formulation of a preventative policy. We evaluated the current prevalence of childhood asthma in Seoul and its trends and related factors.

Methods

The project was conducted annually from 2011 to 2016 and involved around 35 000 children aged 1-13 years. Based on the International Study of Asthma and Allergies in Childhood guidelines, the survey involved parents. The associations of the particulate matter (PM₁₀) concentration, and the number of days on which the daily air quality guidance level was exceeded in the 25 districts of Seoul, with the prevalence of asthma were assessed.

Results

The age-standardized asthma prevalence in 2011 and 2016 was 6.74 and 4.02%, respectively. The prevalence of lifetime asthma treatment and treatment during the last 12 months tended to decrease from 2011 to 2016. Asthma treatment was significantly correlated with the number of days on which the daily air quality guidance level was exceeded, but not with the PM₁₀ concentration.

Conclusions

This study reports the prevalence of asthma among children in Seoul and confirmed the relationship between childhood asthma and known risk factors in a large-scale survey.

Estimates of the Global Burden of Ambient [Formula: see text], Ozone, and [Formula: see text] on Asthma Incidence and Emergency Room Visits

BACKGROUND

Asthma is the most prevalent chronic respiratory disease worldwide, affecting 358 million people in 2015. Ambient air pollution exacerbates asthma among populations around the world and may also contribute to new-onset asthma.

OBJECTIVES

We aimed to estimate the number of asthma emergency room visits and new onset asthma cases globally attributable to fine particulate matter ([Formula: see text]), ozone, and nitrogen dioxide ([Formula: see text]) concentrations.

METHODS

We used epidemiological health impact functions combined with data describing population, baseline asthma incidence and prevalence, and pollutant concentrations. We constructed a new dataset of national and regional emergency room visit rates among people with asthma using published survey data.

RESULTS

We estimated that 9–23 million and 5–10 million annual asthma emergency room visits globally in 2015 could be attributable to ozone and [Formula: see text], respectively, representing 8–20% and 4–9% of the annual number of global visits, respectively. The range reflects the application of central risk estimates from different epidemiological meta-analyses. Anthropogenic emissions were responsible for [Formula: see text] and 73% of ozone and [Formula: see text] impacts, respectively. Remaining impacts were attributable to naturally occurring ozone precursor emissions (e.g., from vegetation, lightning) and [Formula: see text] (e.g., dust, sea salt), though several of these sources are also influenced by humans. The largest impacts were estimated in China and India.

CONCLUSIONS

These findings estimate the magnitude of the global asthma burden that could be avoided by reducing ambient air pollution. We also identified key uncertainties and data limitations to be addressed to enable refined estimation. https://doi.org/10.1289/EHP3766.

Short-term effect of air pollution on asthma patient visits in Shanghai area and assessment of economic costs

BACKGROUNDS

Shanghai, in China, is one of the highest incidence cities for asthma morbidity. However, few studies have systemically explored the association of ambient air pollutants and asthma patients with economic costs.

OBJECTIVES

The study researched the link of short-term ambient air pollutants exposure and asthma patients in Shanghai. Furthermore, the economic cost was also assessed.

METHODS

We applied the generalized addictive model (GAM) to analyze the association between ambient air pollutants and asthma patients with economic costs assessment.

RESULTS

We investigated a total of 7200 asthma patient visits (inhabitant in Shanghai). A 10 µg m^-3 increase in the current day concentrations of SO₂, CO, NO₂, PM₁₀, O₃ and PM_2.5 corresponded to increase of 3.79% [95% CI: 0.84%, 6.83%], 0.27% [95% CI: 0.14%, 0.40%], 0.63% [95% CI: - 0.81%, 2.10%], 1.11% [95% CI: 0.38%, 1.85%], 0.23% [95% CI: 0.31%, 078%] and 1.27% [95% CI: 0.29%, 2.26%] in daily asthma patient visits. In economic cost level, the economic cost of asthma patients were attributed to ambient air pollutants (SO₂, CO, NO₂, PM₁₀, O₃ and PM_2.5) with 197 million USD losses per year. Among, the economic cost of asthma patient visits were attributed to SO₂, CO, NO₂, PM₁₀, O₃ and PM_2.5 with 101.30, 7.46, 17.15, 30.18, 6.39 and 34.50 million USD loss per year, respectively.

CONCLUSIONS

Short-term exposure to SO₂, CO, NO₂, PM₁₀, O₃ and PM_2.5 were linked to asthma patient visits increase in Shanghai areas. The economic cost of asthma patient visits were attributed to ambient air pollutants (SO₂, CO, O₃, PM₁₀, NO₂ and PM_2.5) with 197 million USD losses per year. The study strengthen our fundamental comprehending of impacts of ambient air pollutants on human health and economy burden.

Influence of Air Pollution on Hospital Admissions in Adult Asthma in Northeast China

Background:

Asthma is a common chronic respiratory disease and is related to air pollution exposure. However, only a few studies have concentrated on the association between air pollution and adult asthma. Moreover, the results of these studies are controversial. Therefore, the present study aimed to analyze the influence of various pollutants on hospitalization due to asthma in adults.

Methods:

A total of 1019 unrelated hospitalized adult asthma patients from Northeast China were recruited from 2014 to 2016. Daily average concentrations of air pollutants (particulate matter <2.5 μm [PM_2.5], particulate matter <10 μm [PM₁₀], sulfur dioxide [SO₂], nitrogen dioxide [NO₂], and carbon monoxide [CO]) were obtained from the China National Environmental Monitoring Centre website from 2014 to 2016. Cox logistic regression analysis was used to analyze the relationship between air pollutants and hospital admissions in adult asthma.

Results:

The maximum odds ratio (OR) value for most air pollutants occurred on lag day 1. Lag day 1 was chosen as the exposure period, and 8 days before onset was chosen as the control period. Three pollutants (PM_2.5, CO, and SO₂) were entered into the regression equation, and the corresponding OR (95% confidence interval) was 0.995 (0.991–0.999), 3.107 (1.607–6.010), and 0.979 (0.968–0.990), respectively.

Conclusions:

A positive association between hospital admissions and the daily average concentration of CO was observed. CO is likely to be a risk factor for hospital admissions in adults with asthma.

The association of environmental, meteorological, and pollen count variables with asthma-related emergency department visits and hospitalizations in the Bronx

Objective: To better understand how meteorological variables, air quality variables, and pollen counts collectively contribute to asthma-related emergency department visits (AREDV) and asthma-related hospitalizations (ARH) among pediatric and adult patients in the New York City borough of the Bronx. Methods: The numbers of daily adult and pediatric AREDV and ARH from 2001 to 2008 were obtained from three Bronx hospitals. After removing outliers, interpolating missing data, and standardizing variable values by scaling the data using z-scores, data were analyzed using Spearman rank tests and linear regression models for the full year and each season. Results: There were a total of 42,065 AREDV and 1,664 ARH at both Bronx hospitals. With the exception of a spring peak in AREDVs, AREDVs and ARHs follow a cyclical pattern, climbing in the fall, plateauing in the winter, dropping in the spring, and reaching a low in the summer. Among the 11 air quality, meteorological, and pollen count variables, temperature and tree pollen made the greatest contribution to AREDV with scaled coefficients of -0.337 and 0.311 respectively; equating to an additional AREDV for every 5.0-unit decrease in temperature and an additional AREDV for every 186.0-unit increase in tree pollen. These two variables were confirmed to have independent associations with AREDV prior to the data interpolation. Grass pollen was also found to have a relatively large contribution to AREDV during the summer with a scaled coefficient of 0.314, equating to an additional AREDV for every 2.3-unit increase in grass pollen. Conclusion: There are distinct peaks of increased AREDVs that are closely associated with increased tree pollen counts in the spring and decreasing temperatures in the fall. Early anticipation of these air quality, meteorological, and pollen factor changes based on ongoing surveillance could potentially guide clinical practice and minimize AREDVs in the Bronx.

Association of airborne particles, protein, and endotoxin with emergency department visits for asthma in Kyoto, Japan

Background

The health effects of biological aerosols on the respiratory system are unclear. The purpose of this study was to clarify the association of airborne particle, protein, and endotoxin with emergency department visits for asthma in Kyoto City, Japan.

Methods

We collected data on emergency department visits at a hospital in Kyoto from September 2014 to May 2016. Fine (aerodynamic diameter ≤ 2.5 μm) and coarse (≥ 2.5 μm) particles were collected in Kyoto, and protein and endotoxin levels were analyzed. The association of the levels of particles, protein, endotoxin, and meteorological factors (temperature, relative humidity, wind speed, and air pressure) with emergency department visits for asthma was estimated.

Results

There were 1 to 15 emergency department visits for asthma per week, and the numbers of visits increased in the autumn and spring, namely many weeks in September, October, and April. Weekly concentration of protein in fine particles was markedly higher than that in coarse particles, and protein concentration in fine particles was high in spring months. Weekly endotoxin concentrations in fine and coarse particles were high in autumn months, including September 2014 and 2015. Even after adjusting for meteorological factors, the concentrations of coarse particles and endotoxin in both particles were significant factors on emergency department visits for asthma.

Conclusions

Our results suggest that atmospheric coarse particles and endotoxin are significantly associated with an increased risk of asthma exacerbation.

Electronic supplementary material

The online version of this article (10.1186/s12199-018-0731-2) contains supplementary material, which is available to authorized users.

Association between air pollution and asthma exacerbations in Badalona, Barcelona (Spain), 2008-2016

INTRODUCTION AND OBJECTIVE

Air pollution has been widely associated with respiratory diseases. Nevertheless, association between air pollution and exacerbations of asthma in our area has been less studied. To analyse the effect of air pollution on exacerbations of asthma in Badalona.

MATERIAL AND METHODS

This was an observational study conducted in Badalona. The number of daily hospital admissions and accident and emergency visits related to exacerbation of asthma between 2008 and 2016 was obtained. We used simple Poisson regressions to test the effects of daily mean temperature, atmospheric pressure, relative humidity, and NO₂, SO₂ and CO levels on asthma-related emergencies and hospitalisations the same day and 1-4 days after. All p-values were corrected for multiple comparisons.

RESULTS

The number of hospitalisations was associated with low temperature (lags 0 to 4) and higher levels of NO₂ (lags 0, 1, 2 and 4) and atmospheric pressure (lags 2 and 3). The number of accident and emergency visits was associated with low temperature (lags 0 to 4) and higher levels of NO₂ (lags 2, 3 and 4).

CONCLUSIONS

The number of accident and emergency visits and hospitalisations for exacerbation of asthma is associated with higher levels of NO₂ and with lower temperatures.

Air pollution and resistance to inhaled glucocorticoids: Evidence, mechanisms and gaps to fill

Substantial evidence indicates that cigarette smoke exposure induces resistance to glucocorticoids, the primary maintenance medication in asthma treatment. Modest evidence also suggests that air pollution may reduce the effectiveness of these critical medications. Cigarette smoke, which has clear parallels with air pollution, has been shown to induce glucocorticoid resistance in asthma and it has been speculated that air pollution may have similar effects. However, the literature on an association of air pollution with glucocorticoid resistance is modest to date. In this review, we detail the evidence for, and against, the effects of air pollution on glucocorticoid effectiveness, focusing on results from epidemiology and controlled human exposure studies. Epidemiological studies indicate a correlation between increased air pollution exposure and worse asthma symptoms. But these studies also show a mix of beneficial and harmful effects of glucocorticoids on spirometry and asthma symptoms, perhaps due to confounding influences, or the induction of glucocorticoid resistance. We describe mechanisms that may contribute to reductions in glucocorticoid responsiveness following air pollution exposure, including changes to phosphorylation or oxidation of the glucocorticoid receptor, repression by cytokines, or inflammatory pathways, and epigenetic effects. Possible interactions between air pollution and respiratory infections are also briefly discussed. Finally, we detail a number of therapies that may boost glucocorticoid effectiveness or reverse resistance in the presence of air pollution, and comment on the beneficial effects of engineering controls, such as air filtration and asthma action plans. We also call attention to the benefits of improved clean air policy on asthma. This review highlights numerous gaps in our knowledge of the interactions between air pollution and glucocorticoids to encourage further research in this area with a view to reducing the harm caused to those with airways disease.

A Closer Look at the Bivariate Association between Ambient Air Pollution and Allergic Diseases: The Role of Spatial Analysis

Although previous ecological studies investigating the association between air pollution and allergic diseases accounted for temporal or seasonal relationships, few studies address spatial non-stationarity or autocorrelation explicitly. Our objective was to examine bivariate correlation between outdoor air pollutants and the prevalence of allergic diseases, highlighting the limitation of a non-spatial correlation measure, and suggesting an alternative to address spatial autocorrelation. The 5-year prevalence data (2011⁻2015) of allergic rhinitis, atopic dermatitis, and asthma were integrated with the measures of four major air pollutants (SO₂, NO₂, CO, and PM₁₀) for each of the 423 sub-districts of Seoul. Lee's L statistics, which captures how much bivariate associations are spatially clustered, was calculated and compared with Pearson's correlation coefficient for each pair of the air pollutants and allergic diseases. A series of maps showing spatiotemporal patterns of allergic diseases at the sub-district level reveals a substantial degree of spatial heterogeneity. A high spatial autocorrelation was observed for all pollutants and diseases, leading to significant dissimilarities between the two bivariate association measures. The local L statistics identifies the areas where a specific air pollutant is considered to be contributing to a type of allergic disease. This study suggests that a bivariate correlation measure between air pollutants and allergic diseases should capture spatially-clustered phenomenon of the association, and detect the local instability in their relationships. It highlights the role of spatial analysis in investigating the contribution of the local-level spatiotemporal dynamics of air pollution to trends and the distribution of allergic diseases.

An approach estimating the short-term effect of NO2 on daily mortality in Spanish cities

BACKGROUND

Road traffic is the most significant source of urban air pollution. PM_2.5 is the air pollutant whose health effects have been most closely studied, and is the variable most commonly used as a proxy indicator of exposure to air pollution, whereas evidence on NO₂ concentrations per se is still under study. In the case of Spain, there are no specific updated studies which calculate short-term NO₂-related mortality.

OBJECTIVE

To quantify the relative risks (RRs) and attributable risks (ARs) of daily mortality associated with NO₂ concentrations recorded in Spain across the study period, 2000-2009; and to calculate the number of NO₂-related deaths.

MATERIAL AND METHODS

We calculated daily mortality due to natural causes (ICD-10: A00 R99), circulatory causes (ICD-10: I00 I99) and respiratory causes (ICD-10: J00 J99) for each province across the period 2000-2009, using data supplied by the National Statistics Institute. Mean daily NO₂ concentrations in μg/m³ for each provincial capital were furnished by the Ministry of Agriculture & Environment, along with the equivalent figures for the control pollutants (PM₁₀). To estimate RRs and ARs, we used generalised linear models with a Poisson link, controlling for maximum and minimum daily temperature, trend of the series, seasonalities, and the autoregressive nature of the series. A meta-analysis with random effects was used to estimate RRs and ARs nationwide.

RESULTS

The overall RRs obtained for Spain, corresponding to increases of 10 μg/m³ in NO₂ concentrations were 1.012 (95% CI: 1.010 1.014) for natural-cause mortality, 1.028 (95% CI: 1.019 1.037) for respiratory-cause mortality, and 1.016 (95% CI: 1.012 1.021) for circulatory-cause mortality. This amounted to an annual overall 6085 deaths (95% CI: 3288 9427) due to natural causes, 1031 (95% CI: 466 1585) due to respiratory causes, and 1978 (95% CI: 828 3197) due to circulatory causes.

CONCLUSION

By virtue of the number of cities involved and the nature of the analysis performed, with quantification of the RRs and ARs of the short-term impact of NO₂ on daily mortality in Spain, this study provides an updated estimate of the effect had by this type of pollutant on causes of mortality, and constitutes an important basis for reinforcing public health measures at a national level.

A Muscarinic Antagonist Reduces Airway Inflammation and Bronchoconstriction Induced by Ambient Particulate Matter in a Mouse Model of Asthma

Ambient particulate matter (PM) can increase airway inflammation and induce bronchoconstriction in asthma. This study aimed to investigate the effect of tiotropium bromide, a long-acting muscarinic antagonist, on airway inflammation and bronchoconstriction induced by ambient PM in a mouse model of asthma. We compared the effect of tiotropium bromide to that of fluticasone propionate and formoterol fumarate. BALB/c mice were sensitized to ovalbumin (OVA) via the airways and then administered tiotropium bromide, fluticasone propionate, or formoterol fumarate. Mice were also sensitized to ambient PM via intranasal instillation. Differential leukocyte counts and the concentrations of interferon (IFN)-γ, interleukin (IL)-5, IL-6, IL-13, and keratinocyte-derived chemokine (KC/CXCL1) were measured in bronchoalveolar lavage fluid (BALF). Diacron-reactive oxygen metabolites (dROMs) were measured in the serum. Airway resistance and airway inflammation were evaluated in lung tissue 24 h after the OVA challenge. Ambient PM markedly increased neutrophilic airway inflammation in mice with OVA-induced asthma. Tiotropium bromide improved bronchoconstriction, and reduced neutrophil numbers, decreased the concentrations of IL-5, IL-6, IL-13, and KC/CXCL1 in BALF. However, tiotropium bromide did not decrease the levels of dROMs increased by ambient PM. Though eosinophilic airway inflammation was reduced with fluticasone propionate, neutrophilic airway inflammation was unaffected. Bronchoconstriction was improved with formoterol fumarate, but not with fluticasone propionate. In conclusion, tiotropium bromide reduced bronchoconstriction, subsequently leading to reduced neutrophilic airway inflammation induced by ambient PM.

Nitrogen dioxide exposure in school classrooms of inner-city children with asthma

BACKGROUND

Ambient and home exposure to nitrogen dioxide (NO2) causes asthma symptoms and decreased lung function in children with asthma. Little is known about the health effects of school classroom pollution exposure.

OBJECTIVE

We aimed to determine the effect of indoor classroom NO2 on lung function and symptoms in inner-city school children with asthma.

METHODS

Children enrolled in the School Inner-City Asthma Study were followed for 1 academic year. Subjects performed spirometry and had fraction of exhaled nitric oxide values measured twice during the school year at school. Classroom NO2 was collected by means of passive sampling for 1-week periods twice per year, coinciding with lung function testing. Generalized estimating equation models assessed lung function and symptom relationships with the temporally nearest classroom NO2 level.

RESULTS

The mean NO2 value was 11.1 ppb (range, 4.3-29.7 ppb). In total, exposure data were available for 296 subjects, 188 of whom had complete spirometric data. At greater than a threshold of 8 ppb of NO2 and after adjusting for race and season (spirometry standardized by age, height, and sex), NO2 levels were associated highly with airflow obstruction, such that each 10-ppb increase in NO2 level was associated with a 5% decrease in FEV1/forced vital capacity ratio (β = -0.05; 95% CI, -0.08 to -0.02; P = .01). Percent predicted forced expiratory flow between the 25th and 75th percentile of forced vital capacity was also inversely associated with higher NO2 exposure (β = -22.8; 95% CI, -36.0 to -9.7; P = .01). There was no significant association of NO2 levels with percent predicted FEV1, fraction of exhaled nitric oxide, or asthma symptoms. Additionally, there was no effect modification of atopy on lung function or symptom outcomes.

CONCLUSION

In children with asthma, indoor classroom NO2 levels can be associated with increased airflow obstruction.

Short-Term Particulate Air Pollution Exposure is Associated with Increased Severity of Respiratory and Quality of Life Symptoms in Patients with Fibrotic Sarcoidosis

This study aimed to determine if short-term exposure to particulate matter (PM_2.5) and ozone (O₃) is associated with increased symptoms or lung function decline in fibrotic sarcoidosis. Sixteen patients with fibrotic sarcoidosis complicated by frequent exacerbations completed pulmonary function testing and questionnaires every three months for one year. We compared 7-, 10-, and 14-day average levels of PM_2.5 and O₃ estimated at patient residences to spirometry (forced expiratory volume in 1 s (FEV1), to forced vital capacity (FVC), episodes of FEV1 decline > 10%) and questionnaire outcomes (Leicester cough questionnaire (LCQ), Saint George Respiratory Questionnaire (SGRQ), and King's Sarcoidosis Questionnaire (KSQ)) using generalized linear mixed effect models. PM_2.5 level averaged over 14 days was associated with lower KSQ general health status (score change -6.60 per interquartile range (IQR) PM_2.5 increase). PM_2.5 level averaged over 10 and 14 days was associated with lower KSQ lung specific health status (score change -6.93 and -6.91, respectively). PM_2.5 levels were not associated with FEV₁, FVC, episodes of FEV₁ decline > 10%, or respiratory symptoms measured by SGRQ or LCQ. Ozone exposure was not associated with any health outcomes. In this small cohort of patients with fibrotic sarcoidosis, PM_2.5 exposure was associated with increased severity of respiratory and quality of life symptoms.

Taming Asthma in School-Aged Children: A Comprehensive Review

Asthma is the most common chronic disease of childhood and the leading cause of childhood morbidity as measured by school absences, emergency department visits, and hospitalizations. Multiple factors play a role in the development, treatment and prevention of childhood asthma including racial/ethnic and socioeconomic disparities, both the home and school environments, and medication use. The goals of this review are to summarize these aspects of asthma in school-aged children and to present an updated review of medications as it relates to treatment strategies that will help in the care of these children. We conclude that phenotypic heterogeneity and appropriate environmental assessments and interventions are important considerations in the management of childhood asthma.

Effects of personal air pollution exposure on asthma symptoms, lung function and airway inflammation

BACKGROUND

There is evidence that air pollution increases the risk of asthma hospitalizations and healthcare utilization, but the effects on day-to-day asthma control are not fully understood.

OBJECTIVE

We undertook a prospective single-centre panel study to test the hypothesis that personal air pollution exposure is associated with asthma symptoms, lung function and airway inflammation.

METHODS

Thirty-two patients with a clinical diagnosis of asthma were provided with a personal air pollution monitor (Cairclip NO₂ /O₃ ) which was kept on or around their person throughout the 12-week follow-up period. Ambient levels of NO₂ and particulate matter were modelled based upon satellite imaging data. Directly measured ozone, NO₂ and particulate matter levels were obtained from a monitoring station in central Leicester. Participants made daily electronic records of asthma symptoms, peak expiratory flow and exhaled nitric oxide. Spirometry and asthma symptom questionnaires were completed at fortnightly study visits. Data were analysed using linear mixed effects models and cross-correlation.

RESULTS

Cairclip exposure data were of good quality with clear evidence of diurnal variability and a missing data rate of approximately 20%. We were unable to detect consistent relationships between personal air pollution exposure and clinical outcomes in the group as a whole. In an exploratory subgroup analysis, total oxidant exposure was associated with increased daytime symptoms in women but not men.

CONCLUSIONS AND CLINICAL RELEVANCE

We did not find compelling evidence that air pollution exposure impacts on day-to-day clinical control in an unselected asthma population, but further studies are required in larger populations with higher exposure levels. Women may be more susceptible than men to the effects of air pollution, an observation which requires confirmation in future studies.

Shorter telomeres in non-smoking patients with airflow limitation

BACKGROUND

Cross-sectional and longitudinal studies describe shorter telomeres in patients with chronic obstructive pulmonary disease (COPD) compared to matched non-COPD controls, but the relationship is confounded by tobacco consumption. We hypothesized that telomere shortening would be similar between non-smoking and smoking individuals with airflow limitation and shorter than non-obstructed controls.

METHODS

Telomere length (T/S) was measured by qPCR in blood leukocytes of 80 non-smoking patients and 80 age-matched smokers with airflow limitation. Forty non-smoker healthy individuals served as controls. Anthropometrics, lung function, previous and current comorbidities were recorded in all individuals. Relationship between telomere length and clinical and functional variables were explored in the three groups.

RESULTS

Telomeres length was similar in non-smokers and smoker individuals with airflow limitation (T/S = 0.61 ± 0.19 vs. 0.60 ± 0.23, p > 0.05) respectively. Telomere length was significantly shorter in both groups compared to healthy controls (T/S 0.79 ± 0.40; p = 0.01) independent from age and sex. No significant association was found between the telomere length and clinical or lung function parameters.

CONCLUSIONS

Telomere shortening is associated with airflow limitation independent of smoking status. Weather premature ageing or biologically determined shorter telomeres are responsible for this finding remain to be determined.

Ozone exposure and pulmonary effects in panel and human clinical studies: Considerations for design and interpretation

A wealth of literature exists regarding the pulmonary effects of ozone, a photochemical pollutant produced by the reaction of nitrogen oxide and volatile organic precursors in the presence of sunlight. This paper focuses on epidemiological panel studies and human clinical studies of ozone exposure, and discusses issues specific to this pollutant that may influence study design and interpretation as well as other, broader considerations relevant to ozone-health research. The issues are discussed using examples drawn from the wider literature. The recent panel and clinical literature is also reviewed. Health outcomes considered include lung function, symptoms, and pulmonary inflammation. Issues discussed include adversity, reversibility, adaptation, variability in ozone exposure metric used and health outcomes evaluated, co-pollutants in panel studies, influence of temperature in panel studies, and multiple comparisons. Improvements in and standardization of panel study approaches are recommended to facilitate comparisons between studies as well as meta-analyses. Additional clinical studies at or near the current National Ambient Air Quality Standard (NAAQS) of 70 ppb are recommended, as are clinical studies in sensitive subpopulations such as asthmatics.

IMPLICATIONS

The pulmonary health impacts of ozone exposure have been well documented using both epidemiological and chamber study designs. However, there are a number of specific methodological and related issues that should be considered when interpreting the results of these studies and planning additional research, including the standardization of exposure and health metrics to facilitate comparisons among studies.

Application of a Time-Stratified Case-Crossover Design to Explore the Effects of Air Pollution and Season on Childhood Asthma Hospitalization in Cities of Differing Urban Patterns: Big Data Analytics of Government Open Data

Few studies have assessed the lagged effects of levels of different urban city air pollutants and seasons on asthma hospitalization in children. This study used big data analysis to explore the effects of daily changes in air pollution and season on childhood asthma hospitalization from 2001 to 2010 in Taipei and Kaohsiung City, Taiwan. A time-stratified case-crossover study and conditional logistic regression analysis were employed to identify associations between the risk of hospitalization due to asthma in children and the levels of air pollutants (PM_2.5, PM₁₀, O₃, SO₂, and NO₂) in the days preceding hospitalization. During the study period, 2900 children in Taipei and 1337 in Kaohsiung aged ≤15 years were hospitalized due to asthma for the first time. The results indicated that the levels of air pollutants were significantly associated with the risk of asthma hospitalization in children, and seasonal effects were observed. High levels of air pollution in Kaohsiung had greater effects than in Taipei after adjusting for seasonal variation. The most important factor was O₃ in spring in Taipei. In children aged 0-6 years, asthma was associated with O₃ in Taipei and SO₂ in Kaohsiung, after controlling for the daily mean temperature and relative humidity.

A Narrative Review on the Human Health Effects of Ambient Air Pollution in Sub-Saharan Africa: An Urgent Need for Health Effects Studies

An important aspect of the new sustainable development goals (SDGs) is a greater emphasis on reducing the health impacts from ambient air pollution in developing countries. Meanwhile, the burden of human disease attributable to ambient air pollution in sub-Saharan Africa is growing, yet estimates of its impact on the region are possibly underestimated due to a lack of air quality monitoring, a paucity of air pollution epidemiological studies, and important population vulnerabilities in the region. The lack of ambient air pollution epidemiologic data in sub-Saharan Africa is also an important global health disparity. Thousands of air pollution health effects studies have been conducted in Europe and North America, rather than in urban areas that have some of the highest measured air pollution levels in world, including urban areas in sub-Saharan Africa. In this paper, we provide a systematic and narrative review of the literature on ambient air pollution epidemiological studies that have been conducted in the region to date. Our review of the literature focuses on epidemiologic studies that measure air pollutants and relate air pollution measurements with various health outcomes. We highlight the gaps in ambient air pollution epidemiological studies conducted in different sub-regions of sub-Saharan Africa and provide methodological recommendations for future environmental epidemiology studies addressing ambient air pollution in the region.

Cleaner fuels for ships provide public health benefits with climate tradeoffs

We evaluate public health and climate impacts of low-sulphur fuels in global shipping. Using high-resolution emissions inventories, integrated atmospheric models, and health risk functions, we assess ship-related PM_2.5 pollution impacts in 2020 with and without the use of low-sulphur fuels. Cleaner marine fuels will reduce ship-related premature mortality and morbidity by 34 and 54%, respectively, representing a ~ 2.6% global reduction in PM_2.5 cardiovascular and lung cancer deaths and a ~3.6% global reduction in childhood asthma. Despite these reductions, low-sulphur marine fuels will still account for ~250k deaths and ~6.4 M childhood asthma cases annually, and more stringent standards beyond 2020 may provide additional health benefits. Lower sulphur fuels also reduce radiative cooling from ship aerosols by ~80%, equating to a ~3% increase in current estimates of total anthropogenic forcing. Therefore, stronger international shipping policies may need to achieve climate and health targets by jointly reducing greenhouse gases and air pollution.

Cleaner fuels for ships provide public health benefits with climate tradeoffs

We evaluate public health and climate impacts of low-sulphur fuels in global shipping. Using high-resolution emissions inventories, integrated atmospheric models, and health risk functions, we assess ship-related PM2.5 pollution impacts in 2020 with and without the use of low-sulphur fuels. Cleaner marine fuels will reduce ship-related premature mortality and morbidity by 34 and 54%, respectively, representing a ~ 2.6% global reduction in PM2.5 cardiovascular and lung cancer deaths and a ~3.6% global reduction in childhood asthma. Despite these reductions, low-sulphur marine fuels will still account for ~250k deaths and ~6.4 M childhood asthma cases annually, and more stringent standards beyond 2020 may provide additional health benefits. Lower sulphur fuels also reduce radiative cooling from ship aerosols by ~80%, equating to a ~3% increase in current estimates of total anthropogenic forcing. Therefore, stronger international shipping policies may need to achieve climate and health targets by jointly reducing greenhouse gases and air pollution.

School Environmental Intervention Programs

Exposure to indoor allergens and pollutants plays a significant part in the development of asthma and its associated morbidity. Inner-city children with asthma are disproportionately affected by these exposures with increased asthma morbidity. Although years of previous research have linked exposures in the urban home environment with significant childhood asthma disease, many of these allergens are also present in inner-city school environments. Therefore, evaluation of the school environment of patients with asthma is also essential. School-based environmental interventions may offer benefit for this problem and has the potential to help many children with asthma at once in a cost-effective manner. It is important that environmental health researchers continue to assess which interventions are most practical and result in the greatest measurable improvements.

Association of outdoor air pollution with the prevalence of asthma in children of Latin America and the Caribbean: A systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the association between asthma prevalence and outdoor air pollution in children in Latin America and the Caribbean.

DATA SOURCES

We searched studies in global and regional databases: PubMed, Scopus, LILACS and SciELO.

STUDY SELECTION

Articles following a cross-sectional design, studying children from 0 to 18 years old, and comparing the prevalence of asthma in two or more areas of LAC countries with different air pollution levels were included. The exclusion criteria comprised air pollution not related to human activities.

RESULTS

Database searches retrieved 384 records, while 20 studies were retained for qualitative and 16 for quantitative analysis, representing 48 442 children. We found a positive association, i.e. a higher prevalence of asthma in children living in a polluted environment, with pooled odds ratio (OR) of 1.34 (95% CI: 1.17-1.54). Heterogeneity between studies was moderate (I²: 68.39%), while the risk of bias was intermediate or high in 14 studies. In all the subgroup and sensitivity analyses, the pooled ORs were significant and higher than those found in the general analysis Conclusions: Our results showed that living in a polluted environment is significantly associated with children having asthma in LAC. Limitations of this study include the low number of studies performed in LAC countries, differences in methodologies and the risk of bias in individual studies.

Land cover and air pollution are associated with asthma hospitalisations: A cross-sectional study

BACKGROUND

There is increasing policy interest in the potential for vegetation in urban areas to mitigate harmful effects of air pollution on respiratory health. We aimed to quantify relationships between tree and green space density and asthma-related hospitalisations, and explore how these varied with exposure to background air pollution concentrations.

METHODS

Population standardised asthma hospitalisation rates (1997-2012) for 26,455 urban residential areas of England were merged with area-level data on vegetation and background air pollutant concentrations. We fitted negative binomial regression models using maximum likelihood estimation to obtain estimates of asthma-vegetation relationships at different levels of pollutant exposure.

RESULTS

Green space and gardens were associated with reductions in asthma hospitalisation when pollutant exposures were lower but had no significant association when pollutant exposures were higher. In contrast, tree density was associated with reduced asthma hospitalisation when pollutant exposures were higher but had no significant association when pollutant exposures were lower.

CONCLUSIONS

We found differential effects of natural environments at high and low background pollutant concentrations. These findings can provide evidence for urban planning decisions which aim to leverage health co-benefits from environmental improvements.

Mechanistic insight into the impact of nanomaterials on asthma and allergic airway disease

Asthma is a chronic respiratory disease known for its high susceptibility to environmental exposure. Inadvertent inhalation of engineered or incidental nanomaterials is a concern for human health, particularly for those with underlying disease susceptibility. In this review we provide a comprehensive analysis of those studies focussed on safety assessment of different nanomaterials and their unique characteristics on asthma and allergic airway disease. These include in vivo and in vitro approaches as well as human and population studies. The weight of evidence presented supports a modifying role for nanomaterial exposure on established asthma as well as the development of the condition. Due to the variability in modelling approaches, nanomaterial characterisation and endpoints used for assessment in these studies, there is insufficient information for how one may assign relative hazard potential to individual nanoscale properties. New developments including the adoption of standardised models and focussed in vitro and in silico approaches have the potential to more reliably identify properties of concern through comparative analysis across robust and select testing systems. Importantly, key to refinement and choice of the most appropriate testing systems is a more complete understanding of how these materials may influence disease at the cellular and molecular level. Detailed mechanistic insight also brings with it opportunities to build important population and exposure susceptibilities into models. Ultimately, such approaches have the potential to more clearly extrapolate relevant toxicological information, which can be used to improve nanomaterial safety assessment for human disease susceptibility.

Ambient ozone and asthma hospital admissions in Texas: a time-series analysis

Background

Many studies have evaluated associations between asthma emergency department (ED) visits, hospital admissions (HAs), and ambient ozone (O₃) across the US, but not in Texas. We investigated the relationship between O₃ and asthma HAs, and the potential impacts of outdoor pollen, respiratory infection HAs, and the start of the school year in Texas.

Methods

We obtained daily time-series data on asthma HAs and ambient O₃ concentrations for Dallas, Houston, and Austin, Texas for the years 2003–2011. Relative risks (RRs) and 95% confidence intervals (CIs) of asthma HAs per 10-ppb increase in 8-h maximum O₃ concentrations were estimated from Poisson generalized additive models and adjusted for temporal trends, meteorological factors, pollen, respiratory infection HAs, day of the week, and public holidays. We conducted a number of sensitivity analyses to assess model specification.

Results

We observed weak associations between total asthma HAs and O₃ at lags of 1 day (RR_{10 ppb} = 1.012, 95% CI: 1.004–1.021), 2 days (RR_{10 ppb} = 1.011, 95% CI: 1.002–1.019), and 0–3 days (RR_{10 ppb} = 1.017, 95% CI: 1.005–1.030). The associations were primarily observed in children aged 5–14 years (e.g., for O₃ at lag 0–3 days, RR_{10 ppb} = 1.037, 95% CI: 1.011–1.064), and null in individuals 15 years or older. The effect estimates did not change significantly with adjustment for pollen and respiratory infections, but they attenuated considerably and lost statistical significance when August and September data were excluded. A significant interaction between time around the start of the school year and O₃ at lag 2 day was observed, with the associations with pediatric asthma HAs stronger in August and September (RR_{10 ppb} = 1.040, 95% CI: 1.012–1.069) than in the rest of the year (October–July) (RR_{10 ppb} = 1.006, 95% CI: 0.986–1.026).

Conclusions

We observed small but statistically significant positive associations between total and pediatric asthma HAs and short-term O₃ exposure in Texas, especially in August and September. Further research is needed to determine how the start of school could modify the observed association between O₃ and pediatric asthma HAs.

Electronic supplementary material

The online version of this article (doi:10.1186/s40733-017-0034-1) contains supplementary material, which is available to authorized users.

Fine Particulate Matter and Emergency Room Visits for Respiratory Illness. Effect Modification by Oxidative Potential

RATIONALE

Fine particulate air pollution (PM2.5; particulate matter 2.5 μm or less in diameter) is thought to contribute to acute respiratory morbidity in part through oxidative stress.

OBJECTIVES

To examine the association between PM2.5 oxidative burden and emergency room visits for respiratory illnesses.

METHODS

We conducted a case-crossover study in Ontario, Canada between 2004 and 2011, including 127,836 cases of asthma, 298,751 cases of chronic obstructive pulmonary disease, and more than 1.1 million cases of all respiratory illnesses. Daily air pollution data were collected from ground monitors, and city-level PM2.5 oxidative potential was measured on the basis of a synthetic respiratory tract lining fluid containing the antioxidants glutathione and ascorbate. Conditional logistic regression was used to estimate associations between air pollution concentrations and emergency room visits, adjusting for time-varying covariates.

MEASUREMENTS AND MAIN RESULTS

Three-day mean PM2.5 concentrations were consistently associated with emergency room visits for all respiratory illnesses. Among children (<9 yr), each interquartile change (5.92 μg/m(3)) in 3-day mean PM2.5 was associated with a 7.2% (95% confidence interval, 4.2-10) increased risk of emergency room visits for asthma. Glutathione-related oxidative potential modified the impact of PM2.5 on emergency room visits for respiratory illnesses (P = 0.001) but only at low concentrations (≤10 μg/m(3)). Between-city differences in ascorbate-related oxidative potential did not modify the impact of PM2.5 on respiratory outcomes.

CONCLUSIONS

Between-city differences in glutathione-related oxidative potential may modify the impact of PM2.5 on acute respiratory illnesses at low PM2.5 concentrations. This may explain in part how small changes in ambient PM2.5 mass concentrations can contribute to acute respiratory morbidity in low-pollution environments.