Respiratory health and long-term exposure to air pollutants in Swiss schoolchildren. SCARPOL Team. Swiss Study on Childhood Allergy and Respiratory Symptoms with Respect to Air Pollution, Climate and Pollen

Frequent occurrence of respiratory symptoms in children is associated with exposure to air pollution, land use types, and parental mental health in the Greater Taipei area

Although studies have investigated the individual effects of air pollution, land use types, and parental mental health on children's respiratory health, few studies have examined the effects of these risk factors simultaneously in children aged <2 years. We investigated the effects of exposure to air pollution, land use types surrounding residences, and parental mental health on the frequent occurrence of respiratory symptoms in children aged <2 years in the Greater Taipei area. Participants were recruited from an ongoing Taiwanese birth cohort study. We analyzed the data of the participants who had been recruited from January 2011 to April 2014 and had responded to the follow-up questionnaires at 6, 12, and 24 months. Self-administered questionnaires were used to collect participants' sociodemographic background and health, such as respiratory symptoms, and parental mental health. Pre- and postnatal pollution levels were estimated using the spatial interpolation technique (ordinary kriging) at children's residential addresses. Land use types surrounding participants' homes were evaluated by performing buffer analysis. Multiple logistic regression analyses were conducted to examine the effects of risk factors on the frequent occurrence of child respiratory symptoms in children aged 6, 12, and 24 months. We included 228, 360, and 441 children aged 6, 12, and 24 months, respectively. Our results indicated that postnatal exposure to PM_2.5 and O₃ was positively associated with children's respiratory symptoms. Traffic-related land-use types, sports facilities, and commercial land surrounding homes exerted adverse effects on children's respiratory symptoms, whereas the presence of schools in the neighborhood was beneficial. Parental mental health was also associated with children's respiratory symptoms. Postnatal exposure to air pollution and land use types surrounding residences were associated with respiratory health in children aged <2 years. The residential environment is a critical factor affecting children's respiratory health of children aged <2 years.

Risk factors of chronic cough in China: a systematic review and meta-analysis

OBJECTIVES

Risk factors of chronic cough in China have not been systematically analyzed and we hypothesized that risk factors of chronic cough might have distinct characteristics in China. Hence, we performed this meta-analysis focusing on the potential risk factors of chronic cough in China.

METHODS

We searched 7 databases for studies published before May 8, 2021. This systematic review was performed in accordance with the PRISMA checklist.

RESULTS

A total of 33 eligible articles were identified and included in this systematic review, and 28 studies were included in the meta-analysis. Our results showed that allergy (OR: 3.72; 95% CI: 1.85-7.47), nasal/sinusitis diseases (OR: 3.56; 95% CI: 2.02-6.29), family history of allergy (OR = 1.74; 95% CI: 1.59-1.90), family history of chronic respiratory diseases (OR = 1.67; 95% CI: 1.47-1.91), exposure to pollutants (OR = 1.60; 95% CI: 1.26-2.04), passive smoking (OR = 1.44; 95% CI: 1.32-1.57), and exposure to pets (OR = 1.37; 95% CI: 1.18-1.58) were risk factors for chronic cough in China.

CONCLUSIONS

Our study indicated some potential risk factors of chronic cough in China, which provides useful epidemiological information for managing chronic cough in China and is worthy as a reference for future global investigations.

Irritant-Induced Chronic Cough Triggers: A Scoping Review and Clinical Checklist

Purpose The primary aim of this review was to identify environmental irritants known to trigger chronic cough through the life span and develop a comprehensive clinically useful irritant checklist. Method A scoping review was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analysis Extension for Scoping Reviews, checklist, and explanation. English-language, full-text resources were identified through Medline, PsycINFO, SPORTDiscus, Web of Science, and ProQuest Dissertations and Theses Global. Results A total of 1,072 sources were retrieved; of these, 109 were duplicates. Titles of abstracts of 963 articles were screened, with 295 selected for full-text review. Using the exclusion and inclusion criteria listed, 236 articles were considered eligible and 214 different triggers were identified. Triggers were identified from North America, Europe, Africa, Asia, and Australia. Occupational exposures were also delineated. Conclusions A clinically useful checklist of both frequently encountered triggers and idiosyncratic or rare triggers was developed. The clinical checklist provides a unique contribution to streamline and standardize clinical assessment of irritant-induced chronic cough. The international scope of this review extends the usefulness of the clinical checklist to clinicians on most continents.

RISK EFFECTS OF NEAR-ROADWAY POLLUTANTS AND ASTHMA STATUS ON BRONCHITIC SYMPTOMS IN CHILDREN

Supplemental Digital Content is available in the text.

Background:

Bronchitic symptoms in children pose a significant clinical and public health burden. Exposures to criteria air pollutants affect bronchitic symptoms, especially in children with asthma. Less is known about near-roadway exposures.

Methods:

Bronchitic symptoms (bronchitis, chronic cough, or phlegm) in the past 12 months were assessed annually with 8 to 9 years of follow-up on 6757 children from the southern California Children’s Health Study. Residential exposure to freeway and non-freeway near-roadway air pollution was estimated using a line-source dispersion model. Mixed-effects logistic regression models were used to relate near-roadway air pollutant exposures to bronchitic symptoms among children with and without asthma.

Results:

Among children with asthma, a 2 SD increase in non-freeway exposures (odds ratio [OR]: 1.44; 95% confidence interval [CI]: 1.17, 1.78) and freeway exposures (OR: 1.31; 95% CI: 1.06, 1.60) were significantly associated with increased risk of bronchitic symptoms. Among children without asthma, only non-freeway exposures had a significant association (OR: 1.14; 95% CI: 1.00, 1.29). Associations were strongest among children living in communities with lower regional particulate matter.

Conclusions:

Near-roadway air pollution was associated with bronchitic symptoms, especially among children with asthma and those living in communities with lower regional particulate matter. Better characterization of traffic pollutants from non-freeway roads is needed since many children live in close proximity to this source.

An approach to the asthma-protective farm effect by geocoding: Good farms and better farms

BACKGROUND

The highly consistent association of growing up on a farm with a reduced asthma risk has so far been attributed to direct farm exposure. In contrast, geographic determinants of the larger environment have never been assessed. In this study, the effects of proximity to farms and environmental variables in relation to the residential address on asthma and atopy were assessed.

METHODS

Addresses of 2265 children of the Bavarian arm of the GABRIELA study were converted into geocodes. Proximity to the nearest cow farm was calculated, and environmental characteristics were derived from satellite data or terrestrial monitoring. Bacterial diversity in mattress dust samples was assessed in 501 children by sequencing of the 16S rRNA amplicons. Logistic regression models were used to calculate associations between outcomes and exposure variables.

RESULTS

Asthma and atopy were inversely associated with the presence of a farm within a radius of maximum 100 m. The environmental variables greenness, tree cover, soil sealing, altitude, air pollution differed not only between farm and non-farm children but also between farm children with and without another farm nearby. The latter distinction revealed strong associations with characteristics of traditional farms including a broader diversity of microbial exposure, which mainly contributed to the protective effect on asthma. In non-farm children, the protective effect of a farm nearby was completely explained by consumption of farm milk.

CONCLUSIONS

Clustering of farms within a neighborhood of 100 m is strongly associated with the protective effect on asthma and may represent a more traditional style of farming with broader microbial exposure.

Association of Air Pollution Exposure and Interleukin-13 Haplotype with the Risk of Aggregate Bronchitic Symptoms in Children

Interleukin-13(IL-13) might play an important role in driving aggregate bronchitic symptoms pathogenesis. However, none of the studies assessed the interaction between air pollutants exposure and IL-13 gene on the risk of aggregate bronchitic symptoms in non-asthma children. To assess the independent and joint effects of the exposure to air pollution and IL-13 haplotypes on the risk of aggregate bronchitic symptoms, we conducted a cross-sectional study and focused on non-asthma children. The study population consisted of 2944 children. The effect of each air pollutant on the risk of aggregate bronchitic symptoms was estimated as odds ratios per interquartile range (IQR) change. In the multiple logistic regressions, adjusted for confounding factors, the risk of chronic phlegm was associated with PM_2.5 exposure (aOR, 1.59; 95% CI, 1.07–2.37 per 12.51 μg/m3 change), O₃ exposure (aOR, 1.54 95% CI, 1.05–2.27 per 8.28 ppb change) and SO₂ exposure (aOR, 1.19; 95% CI, 1.02–1.39 per 0.98 ppb change). Our study further provides the evidence that gene-environment interactions between IL-13 haplotype and O₃ exposure on chronic phlegm (95% CI for interaction, 1.01–1.38). Identifying children who are more sensitive to air pollution helps us to provide them an efficient prevention to avoid aggregate bronchitic symptoms.

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Limited studies explored the interactions between IL-13 gene and air pollutants exposure on the risk of bronchitic symptoms.

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Genetic susceptibility of IL-13 may interact with O₃ exposure causing the pathogenesis of bronchitic symptoms.

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Identifying children susceptible to air pollutants helps us to provide them an efficient prevention of bronchitic symptoms.

Genetic susceptibility may interact with specific environmental factors causing the pathogenesis of aggregate bronchitic symptoms. Limited studies have explored the interactions between Interleukin-13 (IL-13) gene and air pollutants exposure on the risk of aggregate bronchitic symptoms. Our study further provides the evidence that gene-environment interactions between IL-13 gene and O₃ exposure may play an important role in aggregate bronchitic symptoms. Identifying children who are more sensitive to air pollutants helps us to provide them an efficient prevention to avoid aggregate bronchitic symptoms.

Elemental analysis of infant airborne particulate exposures

Air pollution is hypothesized to have negative impacts on infant pulmonary health because of infants' increased rates of respiration and ongoing lung development. The severity and type of impact may differ depending on elemental concentrations. We conducted a study of 21 infants <6 months old whose parents carried a small personal particulate monitoring device (RTI MicroPEM) and GPS unit with the infant for 7 days in January and February 2015. The study area was Utah County, UT, USA. Real-time particulate exposure levels, as well as optical density and elemental analysis of the particulate matter (PM), were compared with levels from an outdoor stationary monitor. Infants spent an average of 87.4% of their time indoors. PM levels varied widely by infant and time of day (average=19.07 μg/m³, range=0.63-170.25 μg/m³). Infant particulate exposures were not well approximated by the outdoor monitor. Infants had lower exposures to Sb, Mn, Pb, W and Fe than the outdoor monitor and higher exposures to Cd, Ni and Na. Differences were most pronounced for Na. Brown carbon was only detected by personal monitors and not by the outdoor monitor. Further research is needed to understand the potential implications of indoor elemental exposures on early respiratory development.

Association of Changes in Air Quality With Bronchitic Symptoms in Children in California, 1993-2012

IMPORTANCE

Childhood bronchitic symptoms are significant public and clinical health problems that produce a substantial burden of disease. Ambient air pollutants are important determinants of bronchitis occurrence.

OBJECTIVE

To determine whether improvements in ambient air quality in Southern California were associated with reductions in bronchitic symptoms in children.

DESIGN, SETTING, AND PARTICIPANTS

A longitudinal study involving 4602 children (age range, 5-18 years) from 3 cohorts was conducted during the 1993-2001, 1996-2004, and 2003-2012 years in 8 Southern California communities. A multilevel logistic model was used to estimate the association of changes in pollution levels with bronchitic symptoms.

EXPOSURES

Average concentrations of nitrogen dioxide, ozone, particulate matter with an aerodynamic diameter of less than 10 µm (PM10) and less than 2.5 µm (PM2.5).

MAIN OUTCOMES AND MEASURES

Annual age-specific prevalence of bronchitic symptoms during the previous 12 months based on the parent's or child's report of a daily cough for 3 months in a row, congestion or phlegm other than when accompanied by a cold, or bronchitis.

RESULTS

The 3 cohorts included a total of 4602 children (mean age at baseline, 8.0 years; 2268 girls [49.3%]; 2081 Hispanic white [45.2%]) who had data from 2 or more annual questionnaires. Among these children, 892 (19.4%) had asthma at age 10 years. For nitrogen dioxide, the odds ratio (OR) for bronchitic symptoms among children with asthma at age 10 years was 0.79 (95% CI, 0.67-0.94) for a median reduction of 4.9 ppb, with absolute decrease in prevalence of 10.1%. For ozone, the OR was 0.66 (95% CI, 0.50-0.86) for a median reduction of 3.6 ppb, with an absolute decrease in prevalence of 16.3%. For PM10, the OR was 0.61 (95% CI, 0.48-0.78) for a median reduction of 5.8 µg/m3, with an absolute decrease in prevalence of 18.7%. For PM2.5, the OR was 0.68 (95% CI, 0.53-0.86) for a median reduction of 6.8 µg/m3, with absolute decrease in prevalence of 15.4%. Among children without asthma (n = 3710), the ORs were 0.84 (95% CI, 0.76-0.92) for nitrogen dioxide; 0.85 (95% CI, 0.74-0.97) for ozone, 0.80 (95% CI, 0.70-0.92) for PM10, and 0.79 (95% CI, 0.69-0.91) for PM2.5; with absolute decrease in prevalence of 1.8% for nitrogen dioxide, 1.7% for ozone, 2.2% for PM10, and 2.3% for PM2.5. The associations were similar or slightly stronger at age 15 years.

CONCLUSIONS AND RELEVANCE

Decreases in ambient pollution levels were associated with statistically significant decreases in bronchitic symptoms in children. Although the study design does not establish causality, the findings support potential benefit of air pollution reduction on asthma control.

Beirut Air Pollution and Health Effects - BAPHE study protocol and objectives

Background

Recent studies investigating the health effects of air pollution have proven an existing impact around and below international air quality guidelines and standards. These studies were based on accessible data from official registers managed by public authorities. The protocol followed in BAPHE project is described; its benefits and disadvantages are presented and discussed in this paper.

Methods

Based on the review of several international studies we developed a custom made approach in BAPHE (Beirut Air Pollution and Health Effects) project in order to analyze the short term health effects of air pollution taking into consideration the lack of data availability from official sources.

Results

PM_2.5 and PM₁₀ concentrations were measured in Beirut for the period starting from the 1^st of January 2012 to the 31^st of December 2012. The annual average concentrations of PM₁₀ and PM_2.5 exceeded WHO’s annual average limits by 150 % and 200 %, respectively. Health data for 11,567 individuals were collected over 12 months. A variation of hospital admission causes was observed by age categories and gender.

Conclusions

This article presents a simple protocol and the descriptive results of its application in the frame of an eco-epidemiological study in Lebanon. We believe that this work is not only important on a local scale, but it could be helpful for environmental epidemiological studies in other countries.

Air pollution and cytokine responsiveness in asthmatic and non-asthmatic children

Epidemiological studies indicate that asthmatic children are more susceptible to traffic-related air pollution exposure than non-asthmatic children. Local and systemic inflammation in combination with oxidative stress have been suggested as a possible susceptibility factor. We investigated effect modification by asthma status for the association between air pollution exposure and systemic effects using whole blood cytokine responsiveness as an inflammatory marker. The study was nested within the two German birth cohort studies GINIplus and LISAplus and initially designed as a random sub-sample enriched with asthmatic children. Using data from 27 asthmatic and 59 non-asthmatic six-year-old children we measured the production of Interleukin-6 (IL)-6, IL-8, IL-10, monocyte chemotactic protein-1 (MCP-1), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in whole blood after ex-vivo stimulation with urban particulate matter (EHC-93). Air pollution exposure (nitrogen dioxide (NO2), nitrogen oxides (NOx), particulate matter with an aerodynamic diameter <10μm (PM10), particulate matter with an aerodynamic diameter <2.5μm (PM2.5mass), coarse particulate matter (PMcoarse) and PM2.5absorbance (PM2.5abs)) was modelled for children´s home addresses applying land-use regression. To assess effect modification by asthma status linear regression models with multiplicative interaction terms were used. In asthmatics exposure to NO2 was associated with higher production of pro-inflammatory cytokines: adjusted means ratio (MR) 2.22 (95% confidence interval 1.22-4.04) for IL-6 per 2.68µg/m³ NO2. The interaction term between asthma status and NO2 exposure was significant. Results for NOx, PM10, PM2.5mass and PM2.5abs were in the same direction. No association between air pollution and cytokine responsiveness was found in the group of non-asthmatic children and in the overall group. Traffic-related air pollution exposure is associated with higher pro-inflammatory cytokine responsiveness in whole blood of asthmatic children.

Short-term relationships between emergency hospital admissions for respiratory and cardiovascular diseases and fine particulate air pollution in Beirut, Lebanon

High levels of major outdoor air pollutants have been documented in Lebanon, but their health effects remain unknown. The Beirut Air Pollution and Health Effects study aimed to determine the relationship between short-term variations in ambient concentrations of particulate matter (PM10 and PM2.5) and emergency hospital admissions in the city of Beirut, and whether susceptible groups are more greatly affected. An autoregressive Poisson model was used to evaluate the association between daily concentrations of particulate matter and respiratory and cardiovascular emergency hospital admissions after controlling for confounders. All variables were measured during 1 year from January 2012 to December 2012. Relative risks of admissions for respiratory and cardiovascular diseases were calculated for an increase in 10 μg.m(-3) of pollutant concentrations. Total respiratory admissions were significantly associated with the levels of PM10 (1.012 [95% CI 1.004-1.02]) per 10 μg.m(-3) rise in daily mean pollutant concentration for PM10 and 1.016 [95% CI 1.000-1.032] for PM2.5 on the same day. With regard to susceptible groups, total respiratory admissions were associated with PM2.5 and PM10 within the same day in children (relative risk (RR), 1.013 and 1.014; 95% confidence interval, 0.985-1.042 and 1.000-1.029 for PM2.5 and PM10, respectively). Moreover, a nearly significant association was found between particles and total circulatory admissions for adults and elderly groups in the same day. These results are similar to other international studies. Therefore, air pollution control is expected to reduce the number of admissions of these diseases in Lebanon.

Public-health impact of outdoor air pollution for 2(nd) air pollution management policy in Seoul metropolitan area, Korea

Objectives

Air pollution contributes to mortality and morbidity. We estimated the impact of outdoor air pollution on public health in Seoul metropolitan area, Korea. Attributable cases of morbidity and mortality were estimated.

Methods

Epidemiology-based exposure-response functions for a 10 μg/m3 increase in particulate matter (PM_2.5 and PM₁₀) were used to quantify the effects of air pollution. Cases attributable to air pollution were estimated for mortality (adults ≥ 30 years), respiratory and cardiovascular hospital admissions (all ages), chronic bronchitis (all ages), and acute bronchitis episodes (≤18 years). Environmental exposure (PM_2.5 and PM₁₀) was modeled for each 3 km × 3 km.

Results

In 2010, air pollution caused 15.9% of total mortality or approximately 15,346 attributable cases per year. Particulate air pollution also accounted for: 12,511 hospitalized cases of respiratory disease; 20,490 new cases of chronic bronchitis (adults); 278,346 episodes of acute bronchitis (children). After performing the 2^nd Seoul metropolitan air pollution management plan, the reducible death number associated with air pollution is 14,915 cases per year in 2024. We can reduce 57.9% of death associated with air pollution.

Conclusion

This assessment estimates the public-health impacts of current patterns of air pollution. Although individual health risks of air pollution are relatively small, the public-health consequences are remarkable. Particulate air pollution remains a key target for public-health action in the Seoul metropolitan area. Our results, which have also been used for economic valuation, should guide decisions on the assessment of environmental health-policy options.

Effects of particulate air pollution on nasal and lung function development among Greek children: a 19-year cohort study

The aim was to investigate respiratory symptoms, lung function and nasal airflow development among a cohort of children who were exposed to particulate air pollution. We used questionnaires, spirometry and rhinomanometry, while central-monitored PM10 concentrations were used for exposure assessment. We initially examined 1046 children (10-12 year old) in the heavily polluted town of Ptolemaida, Greece, and 379 children in the cleaner town of Grevena (control group). We re-evaluated 312 of the former and 119 of the latter after 19 years. PM10 concentrations were above permissible levels in Ptolemaida during all study period. At both visits, nasal flow was significantly lower in the study sample. At the follow-up visit, 34.3% had severe nasal obstruction (< 500 ml/s) and 38.5% reported chronic nasal symptoms. Spirometric parameters did not differ compared to the control group. Particulate air pollution had significant and negative effects on nasal but not on lung function development.

Shape of concentration-response curves between long-term particulate matter exposure and morbidities of chronic bronchitis: a review of epidemiological evidence

Numerous studies have assessed the concentration-response (C-R) relationships between long-term exposure to particulate matter (PM) and mortality from cardiopulmonary diseases, but few studies have evaluated the C-R relationships between PM exposure and morbidity of chronic respiratory diseases or their symptoms, and to date no systematic review has been published on the characteristics of the C-R curves between PM exposure and respiratory disease morbidity. Screening of all available studies in Medline identified ten studies with figures or scatter plots showing the C-R relationships between PM exposure and chronic bronchitis or chronic cough/phlegm. The C-R relationships showed ballistic 'S' shaped curves, linear in the low to moderate PM range and flattening out in the high PM range. Moreover, the shape and level of the C-R curves differed markedly between susceptible and nonsusceptible populations. New evidence from a prospective cohort study confirmed that the C-R relationship between PM reduction and beneficial effects on respiratory health may be due to the decreased incidence of respiratory symptoms and increased recovery in individuals with symptoms of bronchitis. Additional studies are needed to assess the C-R relationships between different PM contents and chronic health parameters, especially in geographic areas with high PM pollution and in more susceptible populations. Evidence from prospective cohort studies in developing countries with areas of high PM pollution may help evaluate the burden of chronic respiratory disease attributable to PM pollution and air quality standards.

Chronic effects of ambient air pollution on respiratory morbidities among Chinese children: a cross-sectional study in Hong Kong

BACKGROUND

The chronic health effects from exposure to ambient air pollution are still unclear. This study primarily aims to examine the relationship between long-term exposure to ambient air pollution and respiratory morbidities in Chinese children.

METHODS

A cross-sectional study was conducted among 2,203 school children aged 8-10 in three districts with different air pollution levels in Hong Kong. Annual means for ambient PM10, SO2, NO2 and O3 in each district were used to estimate participants' individual exposure. Two questionnaires were used to collect children's respiratory morbidities and other potential risk factors. Multivariable logistic regression was fitted to estimate the risks of air pollution for respiratory morbidities.

RESULTS

Compared to those in the low-pollution district (LPD), girls in the high-pollution district (HPD) were at significantly higher risk for cough at night (ORadj. = 1.81, 95% CI: 1.71-2.78) and phlegm without colds (ORadj. = 3.84, 95% CI: 1.74-8.47). In addition, marginal significance was reached for elevated risks for asthma, wheezing symptoms, and phlegm without colds among boys in HPD (adjusted ORs: 1.71-2.82), as well as chronic cough among girls in HPD (ORadj. = 2.03, 95% CI: 0.88-4.70).

CONCLUSIONS

Results have confirmed certain adverse effects on children's respiratory health from long-term exposure to ambient air pollution. PM10 may be the most relevant pollutant with adverse effects on wheezing and phlegm in boys. Both PM10 and NO2 may be contributing to cough and phlegm in girls.

A prospective study of the impact of air pollution on respiratory symptoms and infections in infants

RATIONALE

There is increasing evidence that short-term exposure to air pollution has a detrimental effect on respiratory health, but data from healthy populations, particularly infants, are scarce.

OBJECTIVES

To assess the association of air pollution with frequency and severity of respiratory symptoms and infections measured weekly in healthy infants.

METHODS

In a prospective birth cohort of 366 infants of unselected mothers, respiratory health was assessed weekly by telephone interviews during the first year of life (19,106 total observations). Daily mean levels of particulate matter (PM10), nitrogen dioxide (NO2), and ozone (O3) were obtained from local monitoring stations. We determined the association of the preceding week's pollutant levels with symptom scores and respiratory tract infections using a generalized additive mixed model with an autoregressive component. In addition, we assessed whether neonatal lung function influences this association and whether duration of infectious episodes differed between weeks with normal PM10 and weeks with elevated levels.

MEASUREMENTS AND MAIN RESULTS

We found a significant association between air pollution and respiratory symptoms, particularly in the week after respiratory tract infections (risk ratio, 1.13 [1.02-1.24] per 10 μg/m(3) PM10 levels) and in infants with premorbid lung function. During times of elevated PM10 (>33.3 μg/m(3)), duration of respiratory tract infections increased by 20% (95% confidence interval, 2-42%).

CONCLUSIONS

Exposure to even moderate levels of air pollution was associated with increased respiratory symptoms in healthy infants. Particularly in infants with premorbid lung function and inflammation, air pollution contributed to longer duration of infectious episodes with a potentially large socioeconomic impact.

Interleukin-6 via sputum induction as biomarker of inflammation for indoor particulate matter among primary school children in Klang Valley, Malaysia

In the last few years, air within homes have been indicates by various and emerging body as more serious polluted than those outdoor. Prevalence of respiratory inflammation among school children aged 8 and 10 years old attending national primary schools in urban and rural area were conducted in Klang Valley. Two population studies drawn from the questionnaires were used to investigate the association between indoor particulate matter (PM_2.5 & PM₁₀) in a home environment and respiratory implication through the understanding of biological responses. Approximately 430 healthy school children of Standard 2 and Standard 5 were selected. Indication of respiratory symptoms using adaptation questionnaire from American Thoracic Society (1978). Sputum sample collection taken for biological analysis. IL-6 then was analyse by using ELISA techniques. Indoor PM_2.5 and PM₁₀ were measured using Dust Trak Aerosol Monitor. The mean concentration of PM_2.5 (45.38 µg/m³) and PM₁₀ (80.07 µg/m³) in urban home environment is significantly higher compared to those in rural residential area (p=0.001). Similar trend also shows by the prevalence of respiratory symptom. Association were found with PM_2.5 and PM₁₀ with the level of IL-6 among school children. A greater exposure to PM_2.5 and PM₁₀ are associated with higher expression of IL-6 level suggesting that the concentration of indoor particulate in urban density area significantly influence the health of children.

A respiratory alert model for the Shenandoah Valley, Virginia, USA

Respiratory morbidity (particularly COPD and asthma) can be influenced by short-term weather fluctuations that affect air quality and lung function. We developed a model to evaluate meteorological conditions associated with respiratory hospital admissions in the Shenandoah Valley of Virginia, USA. We generated ensembles of classification trees based on six years of respiratory-related hospital admissions (64,620 cases) and a suite of 83 potential environmental predictor variables. As our goal was to identify short-term weather linkages to high admission periods, the dependent variable was formulated as a binary classification of five-day moving average respiratory admission departures from the seasonal mean value. Accounting for seasonality removed the long-term apparent inverse relationship between temperature and admissions. We generated eight total models specific to the northern and southern portions of the valley for each season. All eight models demonstrate predictive skill (mean odds ratio = 3.635) when evaluated using a randomization procedure. The predictor variables selected by the ensembling algorithm vary across models, and both meteorological and air quality variables are included. In general, the models indicate complex linkages between respiratory health and environmental conditions that may be difficult to identify using more traditional approaches.

Active and uncontrolled asthma among children exposed to air stack emissions of sulphur dioxide from petroleum refineries in Montreal, Quebec: a cross-sectional study

BACKGROUND

Little attention has been devoted to the effects on children's respiratory health of exposure to sulphur dioxide (SO2) in ambient air from local industrial emissions. Most studies on the effects of SO(2) have assessed its impact as part of the regional ambient air pollutant mix.

OBJECTIVE

To examine the association between exposure to stack emissions of SO(2) from petroleum refineries located in Montreal's (Quebec) east-end industrial complex and the prevalence of active asthma and poor asthma control among children living nearby.

METHODS

The present cross-sectional study used data from a respiratory health survey of Montreal children six months to 12 years of age conducted in 2006. Of 7964 eligible households that completed the survey, 842 children between six months and 12 years of age lived in an area impacted by refinery emissions. Ambient SO(2) exposure levels were estimated using dispersion modelling. Log-binomial regression models were used to estimate crude and adjusted prevalence ratios (PRs) and 95% CIs for the association between yearly school and residential SO(2) exposure estimates and asthma outcomes. Adjustments were made for child's age, sex, parental history of atopy and tobacco smoke exposure at home.

RESULTS

The adjusted PR for the association between active asthma and SO(2) levels was 1.14 (95% CI 0.94 to 1.39) per interquartile range increase in modelled annual SO(2). The effect on poor asthma control was greater (PR=1.39 per interquartile range increase in modelled SO(2) [95% CI 1.00 to 1.94]).

CONCLUSIONS

Results of the present study suggest a relationship between exposure to refinery stack emissions of SO(2) and the prevalence of active and poor asthma control in children who live and attend school in proximity to refineries.

Health impacts of air pollution: a life course approach for examining predictors of respiratory health in adulthood

PURPOSE

This research applies a life course health development framework to examine the impacts of childhood exposure to air pollution on respiratory health in adulthood.

METHODS

This prospective cohort study uses data collected from children originally studied in the 1970/1980s, including exposure to air pollution, indoor exposures, sociodemographic variables, and health outcomes data. Thirty years later, a self-administered questionnaire was used to collect data from adulthood on health status, occupational and residential histories, socioeconomic status, and lifestyle.

RESULTS

Overall, 29% of respondents were diagnosed with at least one respiratory condition and 24% have persistent respiratory symptoms in adulthood. Significant neighborhood differences in exposure variables and adulthood health outcomes were found. Predictors of adulthood respiratory health include asthma diagnosis or chest illness in childhood, parental record of respiratory symptoms, other medical diagnosis in adulthood, fair/poor self-perceived health, smoking/exposure to smoking, and residing in a property built before 1950. Results suggest that exposure to ambient total suspended particulates in childhood is preventative for diagnosis with at least one respiratory condition in adulthood.

CONCLUSION

Findings suggest that long-term childhood exposure to air pollution does not predict respiratory conditions and symptoms in adulthood. However, respiratory health in childhood predicts adulthood respiratory health, thus suggesting that the health impacts of any exposures that impact respiratory health during critical or sensitive times in childhood are long term.

Comparison of total suspended particulate concentration-response relationships for respiratory symptoms between Chinese children with a different susceptibility status

Few studies have explored concentration-response (C-R) relationships between levels of particulate matter (PM) and respiratory morbidity in terms of the susceptibility of children to respiratory diseases. We sought to determine whether the shapes of C-R curves for comparing total suspended particle (TSP) concentration versus the adjusted prevalence of bronchitis (persistent cough or phlegm) and asthma (current wheeze or asthma) symptoms between children with a different susceptibility status. We used the restricted cubic spline (RCS) function to characterize the C-R relationships between TSP and the adjusted prevalence rates of four respiratory symptoms, after controlling for possible confounding by SO(2) and NO(2) levels, in 11,860 children selected from 18 districts of six cities in Liaoning province. Susceptible children exhibited a 2- to 3-fold elevation in the prevalence of all four respiratory symptoms across the entire TSP range (188-689μg/m(3)). Significant differences in the shapes of C-R curves were evident in children with symptoms of bronchitis (ballistic "S"-shaped curves) and asthma (flattened "U"-shaped curves), as well as between the low and high TSP ranges of such curves, when children were grouped by susceptibility status. A significant linear association between TSP levels and current asthma prevalence was found only among susceptible children exposed to high levels of TSP. The shapes and properties of the TSP-morbidity C-R curves differed significantly by type of respiratory symptom, susceptibility status, and TSP range. More work is required to characterize CR relationships in terms of susceptibility status in countries with different PM levels.

The burden of allergic rhinitis and asthma

Asthma and allergic rhinitis are common health problems that cause major illness and disability worldwide. The prevalence of allergic rhinitis is estimated to range from 10% to 20% in the USA and Europe. Multiple factors contribute to the wide range of reported prevalence rates. These include type of prevalence rate reported (current or cumulative), study selection criteria, age of participants, differences in survey methods, varied geographic locations and socioeconomic status, any of which are significant enough to confound direct comparison between studies. There is no standard set of diagnostic criteria for allergic rhinitis. In most studies, the criteria for diagnosis are based on the subject's reporting, solely by questionnaire and rarely confirmed by skin testing. In addition, most studies focus on hay fever, leaving perennial allergic rhinitis underestimated. Sinus imaging is generally not performed and, therefore, rhinosinusitis not differentiated. Some investigators report 'current' prevalence while others report 'cumulative' or 'lifetime' prevalence. Epidemiologic studies have consistently shown that asthma and rhinitis often coexist in the same patients. The prevalence of asthma is <2% in subjects without rhinitis while it varies from 10% to 40% in patients with rhinitis. Furthermore, the majority of patients with asthma experience rhinitis, which is a factor in the risk for asthma. Despite recognition that allergic rhinitis and asthma are global health problems, there are insufficient epidemiologic data and more data are needed with regard to their etiologic risk factors and natural history. This aim of this review is to enable the reader to discuss prevalence, risk factors and prognosis of allergic rhinitis and asthma.

Gender differences and effect of air pollution on asthma in children with and without allergic predisposition: northeast Chinese children health study

Background

Males and females exhibit different health responses to air pollution, but little is known about how exposure to air pollution affects juvenile respiratory health after analysis stratified by allergic predisposition. The aim of the present study was to assess the relationship between air pollutants and asthmatic symptoms in Chinese children selected from multiple sites in a heavily industrialized province of China, and investigate whether allergic predisposition modifies this relationship.

Methodology/Principal Findings

30139 Chinese children aged 3-to-12 years were selected from 25 districts of seven cities in northeast China in 2009. Information on respiratory health was obtained using a standard questionnaire from the American Thoracic Society. Routine air-pollution monitoring data was used for particles with an aerodynamic diameter ≤10 µm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxides (NO₂), ozone (O₃) and carbon monoxide (CO). A two-stage regression approach was applied in data analyses. The effect estimates were presented as odds ratios (ORs) per interquartile changes for PM₁₀, SO₂, NO₂, O₃, and CO. The results showed that children with allergic predisposition were more susceptible to air pollutants than children without allergic predisposition. Amongst children without an allergic predisposition, air pollution effects on asthma were stronger in males compared to females; Current asthma prevalence was related to PM₁₀ (ORs = 1.36 per 31 µg/m³; 95% CI, 1.08–1.72), SO₂ (ORs = 1.38 per 21 µg/m³; 95%CI, 1.12–1.69) only among males. However, among children with allergic predisposition, more positively associations between air pollutants and respiratory symptoms and diseases were detected in females; An increased prevalence of doctor-diagnosed asthma was significantly associated with SO₂ (ORs = 1.48 per 21 µg/m³; 95%CI, 1.21–1.80), NO₂ (ORs = 1.26 per 10 µg/m³; 95%CI, 1.01–1.56), and current asthma with O₃ (ORs = 1.55 per 23 µg/m³; 95%CI, 1.18–2.04) only among females.

Conclusion/Significance

Ambient air pollutions were more evident in males without an allergic predisposition and more associations were detected in females with allergic predisposition.

Effects of ambient air pollution on pulmonary function among schoolchildren

Literature has shown adverse effects of ambient air pollution exposure on various asthma related outcomes in childhood. However, the associated evidence on pulmonary function effects is still inconsistent. We conducted a population-based study comprised of seventh-grade children in 14 Taiwanese communities. Pulmonary function tests and questionnaires were completed on 3957 subjects. We evaluated the effects of ambient air pollution exposures based on the data collected in 2005-2007 by existing air monitoring stations. Multiple linear mixed effect models were fitted to estimate the relationship between community pollutant levels and pulmonary function indices. After adjustment for individual-level confounders, pulmonary function differed only slightly between communities with different levels of air pollution. We found greater effects of ambient air pollutants on pulmonary function for boys than for girls. Among boys, traffic-related pollutants CO, NOx, NO(2), and NO were generally associated with chronic adverse effects on FVC and FEV(1), and subchronic adverse effects mainly on maximal mid-expiratory flow (MMEF) and peak expiratory flow rate. Among girls, only NOx and NO(2) showed subchronic adverse effects on MMEF. Although effect estimates of SO(2), PM(10), and PM(2.5) were generally negative for boys, none achieved statistical significance. Our data suggests that ambient traffic-related pollution had chronic adverse effects on pulmonary function in schoolchildren, especially for boys.

Air pollution and children's respiratory symptoms in six cities of Northern China

OBJECTIVE

The associations between air pollution and children's respiratory health in the high pollution range have not yet been clearly characterized. We evaluated the effects of outdoor air pollution on respiratory morbidity in children selected from multiple sites in a heavy industrial province of northeastern China.

METHODS

The study included 11,860 children aged 3-12 years, selected from 18 districts of 6 cities in Liaoning province, the participation rate is 89.9%. Informed consent and written responses to surveys about children's historic and current health status, personal and household characteristics, and other information were obtained from parents. A two-stage regression approach was applied in data analyses.

RESULTS

There were wide gradients for TSP (188-689 μg/m(3)), SO(2) (14-140 μg/m(3) and NO(2) (29-94 μg/m(3)) across the 18 districts of 6 cities. The three air pollutants significantly increased the prevalence of persistent cough (21-28%), persistent phlegm (21-30%) and current asthma (39-56%) for each interquartile range increment (172 μg/m(3) for TSP, 69 μg/m(3) for SO(2), 30 μg/m(3) for NO(2)), showing larger between-city effects than within-city. Rates of respiratory symptoms were significantly higher for children with younger age, atopy, respiratory disease in early age, family history of asthma or chronic bronchitis, and tobacco smoke exposure.

CONCLUSION

The high levels of outdoor air pollution in north China are positively associated with children's respiratory symptoms, the associations with TSP appear to be stronger than SO(2) and NO(2).

Chronic 'cough hypersensitivity syndrome': a more precise label for chronic cough

Chronic cough remains a challenge to many clinicians because there is often no diagnostic link to causation, and because indirect antitussives are largely ineffective. Chronic cough can also be a predominant symptom associated with many chronic respiratory diseases such as COPD, asthma and pulmonary fibrosis. Chronic cough itself does impair the quality of life and is associated with psychological impairment. The symptoms associated with chronic cough include persistent tickling or irritating sensation in the chest or throat, hoarse voice, dysphonia or vocal cord dysfunction. Currently, the clinical diagnosis of cough is associated with chronic cough caused by airway eosinophilic conditions such as asthma, gastrooesophageal reflux disease or post-nasal drip (or upper airway syndrome), which implies cause and effect, or with chronic cough associated with other diseases such as COPD, cancer or heart failure, that does not necessarily imply cause and effect. A recently-recognised category is idiopathic cough, with no associated or causative diagnosis. We suggest that there is a better label needed for chronic cough, that includes the common association with a hypersensitive cough response to tussive stimuli such as capsaicin or citric acid. This would invoke a hypersensitive syndrome, and there are good reasons to use a new label that would encompass the problem of chronic cough: the chronic 'cough hypersensitivity syndrome'. This would focus the problem on the cough symptomatology and lead to greater focus on understanding the mechanisms of cough sensitisation, with the ultimate aim of obtaining more effective antitussives.

Effects of air pollution on the respiratory health of children: a study in the capital city of India

Urban air pollutants cause a wide range of acute and chronic effects on the respiratory system of children that can be devastating. In this study, the respiratory health of children was assessed in the capital city of India where the level of air pollution is much above the National Ambient Air Quality Standards. The study was carried out in Delhi, and the findings were compared with those of rural West Bengal and Uttaranchal. The prevalence of respiratory symptoms was determined through a structured respiratory symptomlogy questionnaire and personal interviews. Air quality data were collected from Central and State Pollution Control Boards and also obtained by direct measurements using a portable aerosol monitor. Based on the data collected on the cohort of children participating in this study, 32.1% of children in Delhi suffered from respiratory problems in contrast to 18.2% of rural children (control). The respiratory symptoms were more prevalent in girls than in boys. A strong, statistically significant positive association was observed between PM₁₀ level in Delhi's air and the prevalence of lower respiratory tract symptoms.

Effect of sustained high altitude on asthma patients

Due to factors such as allergen avoidance and the decrease of air pollution, sustained stays in a high-altitude climate have been recommended for asthma patients for a long time. There are also documented effects and favorable influence on the health of permanent residents at high altitude; for example, the frequency of allergic sensitization to house dust mite in asymptomatic subjects is much lower than at sea level. In the context of this article, 'high altitude' means 1500-2500 m above sea level. The aim of the review is to summarize the available data on the effects of a sustained stay of asthmatic patient data between 1500-1800 m above sea level in alpine altitudes (Europe). Climatic conditions in South America or in Africa are completely different from the altitudes discussed in this review. We conclude that the available evidence suggests a significant benefit of high altitude for asthmatic patients, particularly in steroid-dependent patients.

Exposure to particulate air pollution at different living locations and respiratory symptoms in Hong Kong--an application of satellite information

Respiratory ill-health effects due to particulate air exposure at different geographical locations in Hong Kong that aggregate individual living locations were estimated based on satellite information. We assessed the presence of respiratory symptoms of a frequent cough or sputum in school students aged 11-20 years old (n = 9,881). Daily particulate air pollution levels at students' living locations were derived from the surface extinction coefficients measured by satellite and measurements from the air pollutant monitoring stations at ground level. Adjusted odds ratio (OR) [95% CI] of respiratory symptoms was 1.047 [1.005, 1.091] per 10 microg m(-3) increase in PM(10) concentration. Specificity tests showed that adjusted OR of having other symptoms is not significant (p = 0.20-0.94). Exposures to PM(10) at different geographical locations is associated with increased odds of having respiratory symptoms (cough or sputum) but not with other symptoms unrelated to air pollution.

Air pollution and prevalence of bronchitic symptoms among children in Taiwan

BACKGROUND

There were limited studies concerning ambient air pollution exposure on development of bronchitic symptoms among children. These studies provided suggestive but inconclusive results. Therefore, the objective of this study is to assess the association between air pollutants and the prevalence of bronchitic symptoms in the Taiwan Children Health Study.

METHODS

We conducted a nationwide cross-sectional study of 5,049 Taiwanese children in 2007. Routine air pollution monitoring data were used for sulfur dioxide (SO(2)), nitrogen dioxides (NO(2)), ozone (O(3)), carbon monoxide (CO), and particles with an aerodynamic diameter ≤ 2.5 μm (PM(2.5)). The exposure parameters were calculated using the between-community 3-year average concentration. The effect estimates were presented as odds ratios (ORs) per interquartile changes for SO(2), NO(2), O(3), CO, and PM(2.5).

RESULTS

In the two-stage hierarchical model adjusting for confounding, the prevalence of bronchitic symptoms with asthma was positively associated with the between-community 3-year average concentrations of NO(2) (adjusted OR, 1.81 per 8.79 ppb; 95% CI, 1.14-2.86), and CO (OR, 1.31 per 105 ppb; 95% CI, 1.04-1.64). The prevalence of phlegm with no asthma was related to O(3) (OR, 1.32 per 8.77 ppb; 95% CI, 1.06-1.63).

CONCLUSIONS

The results suggest that long-term exposure to outdoor air pollutants, such as NO(2), CO, and O(3), may increase the prevalence of bronchitic symptoms among children.

Chronic respiratory symptoms and diseases among indigenous children

Children from Indigenous populations experience more frequent, severe, and recurrent lower respiratory infections as infants and toddlers. The consequences of these infections are chronic lung disorders manifested by recurrent wheezing and chronic productive cough. These symptoms are aggravated more frequently by active and passive tobacco smoke exposure among Indigenous groups. Therapies for these symptoms, although not specific to children of Indigenous origins, are described as is the evidence for their use.

Respiratory symptoms in children living near busy roads and their relationship to vehicular traffic: results of an Italian multicenter study (SIDRIA 2)

BACKGROUND

Epidemiological studies have provided evidence that exposure to vehicular traffic increases the prevalence of respiratory symptoms and may exacerbate pre-existing asthma in children. Self-reported exposure to road traffic has been questioned as a reliable measurement of exposure to air pollutants. The aim of this study was to investigate whether there were specific effects of cars and trucks traffic on current asthma symptoms (i.e. wheezing) and cough or phlegm, and to examine the validity of self-reported traffic exposure.

METHODS

The survey was conducted in 2002 in 12 centers in Northern, Center and Southern Italy, different in size, climate, latitude and level of urbanization. Standardized questionnaires filled in by parents were used to collect information on health outcomes and exposure to traffic among 33,632 6-7 and 13-14 years old children and adolescents. Three questions on traffic exposure were asked: the traffic in the zone of residence, the frequency of truck and of car traffic in the street of residence. The presence of a possible response bias for the self-reported traffic was evaluated using external validation (comparison with measurements of traffic flow in the city of Turin) and internal validations (matching by census block, in the cities of Turin, Milan and Rome).

RESULTS

Overall traffic density was weakly associated with asthma symptoms but there was a stronger association with cough or phlegm (high traffic density OR = 1.24; 95% CI: 1.04, 1.49). Car and truck traffic were independently associated with cough or phlegm. The results of the external validation did not support the existence of a reporting bias for the observed associations, for all the self-reported traffic indicators examined. The internal validations showed that the observed association between traffic density in the zone of residence and respiratory symptoms did not appear to be explained by an over reporting of traffic by parents of symptomatic subjects.

CONCLUSION

Children living in zones with intense traffic are at higher risk for respiratory effects. Since population characteristics are specific, the results of validation of studies on self-reported traffic exposure can not be generalized.

[Allergic respiratory diseases and outdoor air pollution]

INTRODUCTION

After having increased for some time, the prevalence of allergic diseases may have reached a plateau. During this increase, considerable concomitant changes in air pollution have occurred. Photo-oxidant air pollution, related to traffic, has become preponderant. The implication of air pollution in the epidemic of allergies is still debated.

BACKGROUND

Experimental studies have suggested that the effect of air pollutants, including particulates and ozone, on the worsening and even the induction of allergies is biologically plausible. In addition, epidemiological studies have shown a short term impact of the peaks of air pollution on exacerbations of asthma. On the other hand, the results of epidemiological studies dealing with the long-term effects of chronic exposure to air pollution on the prevalence of allergies are less consistent.

VIEWPOINTS

The implementation of new-born cohorts, the use of dispersion models to improve exposure assessment and the study of gene-environment correlations, should increase our knowledge of the role of traffic-related air pollutants in the development of allergies and identify subjects more sensitive to their effects.

CONCLUSIONS

Some traffic-related air pollutants may have played a more important role in the increase in the prevalence of allergies than was assumed from the first epidemiological studies.

Clinical cough VI: the need for new therapies for cough: disease-specific and symptom-related antitussives

Cough is a common symptom that can be self-limiting or persistent. Ideally, treatment of the underlying cause(s) of cough with specific treatments should eliminate cough. This approach may not be successful if no cause can be established or if the treatment of the cause fails. Suppression of cough may be disease-specific or symptom-related. There has been a long tradition in acute cough usually due to upper respiratory tract infections to use symptom-related antitussives. In chronic cough, suppression of cough may be achieved by disease-specific therapies, but in many patients it may be necessary to use symptomatic antitussives. The efficacy of some over-the-counter symptomatic antitussives is often no better than that of a placebo. Currently available cough suppressants include the centrally acting opioids such as morphine, codeine, pholcodeine, and dextromethorphan. Early studies reported success in reducing cough in patients with chronic bronchitis or chronic obstructive pulmonary disease (COPD); however, a carefully conducted blinded controlled study showed no effect of codeine on cough of COPD. Success with these cough suppressants may be achieved at high doses that are associated with side effects. A slow-release preparation of morphine has been shown to have some degree of efficacy, but this should be reserved for the most severe chronic cough patient, and for patients with terminal cancer who may also benefit from its analgesic effects. There are case reports of the success of centrally acting drugs such as amitriptyline, paroxetine, gabapentin, and carbamezepine in chronic cough. New agents derived from basic research such as new opioids such as nociceptin or antagonists of transient receptor potential vanniloid-1 may turn out to have antitussive effects. Efficacy of symptomatic cough suppressants must be tested in double-blind randomized trials using validated measures of cough in patients with chronic cough not responding to specific treatments. Patients with chronic cough need effective antitussives that could be used either on demand or on a long-term basis.

Indoor air quality assessment in and around urban slums of Delhi city, India

The present study aims at investigating the indoor air quality (IAQ) in selected households in one of the urban slums i.e. the Nizamuddin slums in Delhi, the capital city of India. The study includes investigations and assessments on associated health effects on the occupants living in inefficiently designed houses having poor ventilation. The monitoring of indoor air pollutants e.g. the respirable suspended particulate matter (RSPM), the carbon dioxide (CO2), the carbon monoxide (CO), the sulphur dioxide (SO2) and the nitrogen dioxide (NO2) for all three seasons i.e. summer (April-June 2004), rainy (July-September 2004) and winter (December 2004-February 2005) have been conducted. In addition, the spirometry tests on the occupants, particularly the womenfolk and children have been performed to determine the incidence of acute respiratory infections (ARI). Questionnaire survey has also been conducted in the households during the study period to investigate the sick building syndrome (SBS). The study reveals maximum concentration of indoor air pollutants in households during winters (December 2004-February 2005) associated with aggravated respiratory problems like cough, phlegm, wheezing, and breathlessness among occupants particularly the women occupants. Besides, decrement in lung function indices (i.e. FVC and/or FEV1) due to increased concentrations of RSPM and CO2 indoors during winter period has also been observed in the women respondents. The study concludes that women and children indoors are most vulnerable to respiratory problems compared to other sexes. A high SBS score is observed in these 'urban poor' households because of inadequate ventilation.

PRACTICAL IMPLICATIONS

'High indoor airborne pollutants during winter are associated with respiratory problems for women and children in houses in urban slum in Delhi. The work demonstrated the need of further studies of indoor air quality for the 'urban poor' in developing countries.'

Airborne particulate matter and human health: toxicological assessment and importance of size and composition of particles for oxidative damage and carcinogenic mechanisms

Air pollution has been considered a hazard to human health. In the past decades, many studies highlighted the role of ambient airborne particulate matter (PM) as an important environmental pollutant for many different cardiopulmonary diseases and lung cancer. Numerous epidemiological studies in the past 30 years found a strong exposure-response relationship between PM for short-term effects (premature mortality, hospital admissions) and long-term or cumulative health effects (morbidity, lung cancer, cardiovascular and cardiopulmonary diseases, etc). Current research on airborne particle-induced health effects investigates the critical characteristics of particulate matter that determine their biological effects. Several independent groups of investigators have shown that the size of the airborne particles and their surface area determine the potential to elicit inflammatory injury, oxidative damage, and other biological effects. These effects are stronger for fine and ultrafine particles because they can penetrate deeper into the airways of the respiratory tract and can reach the alveoli in which 50% are retained in the lung parenchyma. Composition of the PM varies greatly and depends on many factors. The major components of PM are transition metals, ions (sulfate, nitrate), organic compound, quinoid stable radicals of carbonaceous material, minerals, reactive gases, and materials of biologic origin. Results from toxicological research have shown that PM have several mechanisms of adverse cellular effects, such as cytotoxicity through oxidative stress mechanisms, oxygen-free radical-generating activity, DNA oxidative damage, mutagenicity, and stimulation of proinflammatory factors. In this review, the results of the most recent epidemiological and toxicological studies are summarized. In general, the evaluation of most of these studies shows that the smaller the size of PM the higher the toxicity through mechanisms of oxidative stress and inflammation. Some studies showed that the extractable organic compounds (a variety of chemicals with mutagenic and cytotoxic properties) contribute to various mechanisms of cytotoxicity; in addition, the water-soluble faction (mainly transition metals with redox potential) play an important role in the initiation of oxidative DNA damage and membrane lipid peroxidation. Associations between chemical compositions and particle toxicity tend to be stronger for the fine and ultrafine PM size fractions. Vehicular exhaust particles are found to be most responsible for small-sized airborne PM air pollution in urban areas. With these aspects in mind, future research should aim at establishing a cleared picture of the cytotoxic and carcinogenic mechanisms of PM in the lungs, as well as mechanisms of formation during internal engine combustion processes and other sources of airborne fine particles of air pollution.

Traffic-related air pollution and childhood respiratory symptoms, function and allergies

BACKGROUND

Urban air pollution can trigger asthma symptoms in children, but there is conflicting evidence on effects of long-term exposure on lung function, onset of airway disease and allergic sensitization.

METHODS

The spatial distribution of nitrogen oxides from traffic (traffic-NOx) and inhalable particulate matter from traffic (traffic-PM10) in the study area was assessed with emission databases and dispersion modeling. Estimated levels were used to assign first-year exposure levels for children in a prospective birth cohort (n = 4089), by linking to geocoded home addresses. Parents in 4 Swedish municipalities provided questionnaire data on symptoms and exposures when the children were 2 months and 1, 2, and 4-year-old. At 4 years, 73% of the children underwent clinical examination including peak expiratory flow and specific IgE measurements.

RESULTS

Exposure to air pollution from traffic during the first year of life was associated with an excess risk of persistent wheezing (odds ratio [OR] for 44 microg/m3 [5th-95th percentile] difference in traffic-NOx = 1.60; 95% confidence interval [CI] = 1.09-2.36). Similar results were found for sensitization (measured as specific IgE) to inhalant allergens, especially pollen (OR for traffic-NOx = 1.67; 95% CI = 1.10-2.53), at the age of 4 years. Traffic-related air pollution exposure during the first year of life was also associated with lower lung function at 4 years of age. Results were similar using traffic-NOx and traffic-PM10 as indicators.

CONCLUSIONS

Exposure to moderate levels of locally emitted air pollution from traffic early in life appears to influence the development of airway disease and sensitization in preschool children.

Lag effect of particulate air pollution on lung function in children

We assessed the relationship between particle air pollution and changes in lung function in children as measured by spirometry over time. Data were collected from air pollution and family health examinations of 181 subjects, aged 9-19 years, in a Korean community. The children performed lung function tests, and their height and weight were measured. Their parents responded to an interview regarding the children's history of disease. Data on air pollution were obtained from the Environmental Management Corporation, which is part of the Korean Ministry of the Environment. We found evidence that the declines in forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV(1)) were significantly associated with the PM(10) concentration for 37-60 hr preceding the lung function tests. The associations were consistent in the two-pollutant models. Our findings suggest that exposure to PM(10) may increase the risk of adverse health effects in children with respiratory symptoms or diseases.

Prevalence, pathogenesis, and causes of chronic cough

Cough is a reflex action of the respiratory tract that is used to clear the upper airways. Chronic cough lasting for more than 8 weeks is common in the community. The causes include cigarette smoking, exposure to cigarette smoke, and exposure to environmental pollution, especially particulates. Diseases causing chronic cough include asthma, eosinophilic bronchitis, gastro-oesophageal reflux disease, postnasal drip syndrome or rhinosinusitis, chronic obstructive pulmonary disease, pulmonary fibrosis, and bronchiectasis. Doctors should always work towards a clear diagnosis, considering common and rare illnesses. In some patients, no cause is identified, leading to the diagnosis of idiopathic cough. Chronic cough is often associated with an increased response to tussive agents such as capsaicin. Plastic changes in intrinsic and synaptic excitability in the brainstem, spine, or airway nerves can enhance the cough reflex, and can persist in the absence of the initiating cough event. Structural and inflammatory airway mucosal changes in non-asthmatic chronic cough could represent the cause or the traumatic response to repetitive coughing. Effective control of cough requires not only controlling the disease causing the cough but also desensitisation of cough pathways.

Focusing on children's inhalation dosimetry and health effects for risk assessment: an introduction

Substantial effort has been invested in improving children's health risk assessment in recent years. However, the body of scientific evidence in support of children's health assessment is constantly advancing, indicating the need for continual updating of risk assessment methods. Children's inhalation dosimetry and child-specific adverse health effects are of particular concern for risk assessment. When focusing on this topic within children's health, key issues for consideration include (1) epidemiological evidence of adverse effects following children's exposure to air pollution, (2) ontogeny of the lungs and effects on dosimetry, (3) estimation and variability of children's inhalation rates, and (4) current risk assessment methodologies for addressing children. In this article, existing and emerging information relating to these key issues are introduced and discussed in an effort to better understand children's inhalation dosimetry and adverse health effects for risk assessment. While much useful evidence is currently available, additional research and methods are warranted for improved children's health risk assessment.