Air pollution and respiratory status in asthmatic children: hints for a locally based preventive strategy. AIRE study

Acute respiratory symptoms associated with short term fluctuations in ambient pollutants among schoolchildren in Durban, South Africa

Ambient air pollution has been associated with adverse respiratory outcomes, especially among children with asthma. This study reports on associations between daily ambient air pollutant concentrations and the respiratory symptoms of schoolchildren living in Durban, South Africa. This city is Africa's busiest port and a key hub for imported crude oil and exported refined petroleum and petrochemical products, and it experiences a mixture of air pollutants that reflects emissions from industry, traffic and biomass burning. Children in four communities in the highly industrialized southern portion of the city were compared to children of similar socio-economic profiles living in the north of the city. One school was selected in each community. A total of 423 children were recruited. Symptom logs were completed every 1.5-2 h over 3-week period in each of four seasons. Ambient concentrations of NO₂, NO, SO₂, CO, O_3, PM_2.5 and PM₁₀ were measured throughout the study. Generalized estimating equation (GEE) models were used to estimate odds ratios (ORs) and assess lag effects (1-5 days) using single pollutant (single lags or distributed lags) models. Concentrations of SO₂ and NO_x were markedly higher in the south, while PM₁₀ did not vary. Significant increase in the odds ratios of cough were identified for the various lags analyzed. The OR of symptoms was further increased among those living in the south compared to the north. In conclusion, in this analysis of over 70,000 observations, we provide further evidence that exposure to PM₁₀, SO₂, NO₂ and NO is associated with significantly increased occurrence of respiratory symptoms among children. This was evident for cough, shortness of breath, and chest tightness, across the four pollutants and for different lags of exposure. This is the first study describing these changes in sub-Saharan Africa.

Panel studies of air pollution on children's lung function and respiratory symptoms: a literature review

OBJECTIVE

This article reviews panel studies of air pollution on children's respiratory health and proposes future research directions.

METHODS

The PubMed electronic database was used to search published original epidemiological studies in peer-reviewed journals from 2000 to November 2011. Children's age was limited to ≤18 years old. A total of 33 relevant articles were obtained, with 20 articles relating to lung function, 21 articles relating to respiratory symptoms, and 8 articles examining both.

RESULTS

Most studies suggested the adverse effects of air pollution on children's lung function and respiratory symptoms. Particles and NO(2) showed more significant results, whereas effects of SO(2) were not consistent. A few studies indicated that O(3) interacted with temperature and sometimes seemed to be a protective factor for children's respiratory health. Negative associations between air pollutants and pulmonary health were more serious in asthmatic children than in healthy subjects. However, many outcomes depended on the number of lag days. Peak expiratory flow (PEF) was the most usual measurement for children's lung function, followed by forced expiratory volume in 1 second (FEV(1)).

CONCLUSIONS

There are significant adverse effects of air pollution on children's pulmonary health, especially for asthmatics. Future studies need to examine the lag effects of air pollution on children's lung function and respiratory symptoms. Ambient temperature is predicted to change worldwide due to climate change, which will threaten population health. Further research is needed to examine the effects of ambient temperature and the interactive effects between air pollution and ambient temperature on children's lung function and respiratory symptoms.

Assessing paediatric asthma occurrence through dispensed prescription data and questionnaires

BACKGROUND

The prevalence of asthma, a common disorder in childhood, is often estimated by cross-sectional studies based on questionnaires, with the drawback that estimates are limited to certain age groups and areas. The use of electronic health data is increasingly allowing researchers to overcome these limitations. This study is aimed at assessing asthma occurrence of a school-aged population in Northeast Italy using two different data sources.

METHODS

In 2004, a population-based survey using a standardized questionnaire was conducted to estimate asthma occurrence among a resident population of children aged 6-7 years and adolescents aged 13 years. A selection of dispensed asthma medications was extracted from electronic databases for a 4-year period prior to questionnaire completion (2000-03). Asthma prevalence was estimated by commonly used questionnaire classifications and compared with use of inhaled bronchodilators (alone or in combination) in various time periods. Correlations between the two approaches were calculated.

RESULTS

A total of 10 252 subjects were eligible for analysis (85% of the resident population). A total of 4747 subjects (38% of the resident population) were registered in the drug database during 2000-03. Asthma prevalence was higher in males and in children. Congruence between the two enquiry methods varied according to criteria applied and improved with the protraction of the observation period.

CONCLUSION

A longer period for the capture of medication data yielded higher congruence. A degree of mismatch was observed between the two methods most likely related to factors of drug use and questionnaire reliability. Nonetheless, the benefits of using easily accessible population data prevail, and further studies are warranted.

Symptoms and medication use in children with asthma and traffic-related sources of fine particle pollution

BACKGROUND

Exposure to ambient fine particles [particulate matter < or = 2.5 microm diameter (PM(2.5))] is a potential factor in the exacerbation of asthma. National air quality particle standards consider total mass, not composition or sources, and may not protect against health impacts related to specific components.

OBJECTIVE

We examined associations between daily exposure to fine particle components and sources, and symptoms and medication use in children with asthma.

METHODS

Children with asthma (n = 149) 4-12 years of age were enrolled in a year-long study. We analyzed particle samples for trace elements (X-ray fluorescence) and elemental carbon (light reflectance). Using factor analysis/source apportionment, we identified particle sources (e.g., motor vehicle emissions) and quantified daily contributions. Symptoms and medication use were recorded on study diaries. Repeated measures logistic regression models examined associations between health outcomes and particle exposures as elemental concentrations and source contributions.

RESULTS

More than half of mean PM(2.5) was attributed to traffic-related sources motor vehicles (42%) and road dust (12%). Increased likelihood of symptoms and inhaler use was largest for 3-day averaged exposures to traffic-related sources or their elemental constituents and ranged from a 10% increased likelihood of wheeze for each 5-microg/m(3) increase in particles from motor vehicles to a 28% increased likelihood of shortness of breath for increases in road dust. Neither the other sources identified nor PM(2.5) alone was associated with increased health outcome risks.

CONCLUSIONS

Linking respiratory health effects to specific particle pollution composition or sources is critical to efforts to protect public health. We associated increased risk of symptoms and inhaler use in children with asthma with exposure to traffic-related fine particles.

Asthma symptoms and airway narrowing in children growing up in an urban versus rural environment

The development of asthma and allergy appears to be the result of gene-environment interaction. Potential environmental risk factors such as outdoor and indoor air pollution, infections, allergen exposure, diet, and lifestyle patterns may trigger respiratory symptoms and compromise lung function in children. Specific features of urban and rural lifestyle may constitute distinct risk factors but may also coexist within certain socioeconomic levels. Children of rural environments are at lower risk for asthma and aeroallergen sensitization. The protective effect has been associated with close contact with large animals, but the genetic factor also plays a contributory role. Children with prolonged exposure to urban environment are at increased risk of reduced lung function and those that reside in polluted areas exhibit slower lung growth. It is possible that polluted urban environment per se facilitates subclinical small airway disease. Evidence to date supports a strong relation between residential area as a potential risk factor for childhood asthma symptoms and airway obstruction and a western type of socioeconomic development.

Respiratory health effects among schoolchildren and their relationship to air pollutants in Korea

The objective of this study is to investigate the relationship between five air pollutants (PM(10), SO(2), NO(2), O(3), CO) measured on the daily basis, and adverse health symptoms using epidemiological surveillance data. The generalized estimated equation (GEE) model, a logistic regression analysis model, was used to estimate the effects of air pollution on children's daily health symptoms, focusing on the morbidity including both respiratory and allergic symptoms in four different cities. Analysis of the effects of each pollutant on children's respiratory and allergic symptoms demonstrated that CO affected all symptoms in all the study areas. When the concentration of SO(2) and NO(2) was elevated, upper respiratory symptoms increased significantly. In contrast, when the concentration of O(3) rose, the symptoms decreased significantly. The relationship between measured concentrations and health symptoms was site-dependent for each pollutant.

Environmental tobacco smoke exposure in school children: parent report and urine cotinine measures

BACKGROUND

Environmental tobacco smoke (ETS) in the home continues to be a major health risk for children around the world. Measuring ETS is a central feature of clinical and epidemiological studies, with children's exposure often assessed through parental estimates. The authors examined the relationship between parent-reported estimates of children's exposure to ETS and children's urinary cotinine levels and evaluated the ETS exposure and its effect on respiratory health in children.

METHODS

A total of 188 school children were included in the study. Parents were asked to complete a questionnaire about their smoking habits, their children's respiratory morbidity status and housing conditions. Urinary cotinine levels were measured in children.

RESULTS

According to the responses, 72.3% of the children came from households with smokers, and 34.6% had daily exposure to ETS. When urine cotinine levels of >10 ng/mL were used as the yardstick of exposure, 76% of the children were identified as ETS exposed. No relation was detected between the symptoms of respiratory tract diseases and ETS exposure. To determine the amount of ETS exposure, the contribution of parental reports was low.

CONCLUSION

To evaluate the level of ETS exposure of children, the parents' reports were not reliable. The addition of a biological measure results in a more informative estimate of ETS exposure in children.

Apheis: Health impact assessment of long-term exposure to PM(2.5) in 23 European cities

INTRODUCTION

Apheis aims to provide European decision makers, environmental-health professionals and the general public with up-to-date and easy-to-use information on air pollution (AP) and public health (PH). In the Apheis-3 phase we quantified the PH impact of long-term exposure to PM(2.5) (particulate matter < 2.5 microm) in terms of attributable number of deaths and the potential gain in life expectancy in 23 European cities.

METHODS

We followed the World Health Organization (WHO) methodology for Health Impact Assessment (HIA) and the Apheis guidelines for data collection and analysis. We used the programme created by PSAS-9 for attributable-cases calculations and the WHO software AirQ to estimate the potential gain in life expectancy. For most cities, PM(2.5) levels were calculated from PM10 measurements using a local or European conversion factor.

RESULTS

The HIA estimated that 16,926 premature deaths from all causes, including 11,612 cardiopulmonary deaths and 1901 lung-cancer deaths, could be prevented annually if long-term exposure to PM(2.5 )levels were reduced to 15 microg/m3 in each city. Equivalently, this reduction would increase life expectancy at age 30 by a range between one month and more than two years in the Apheis cities.

CONCLUSIONS

In addition to the number of attributable cases, our HIA has estimated the potential gain in life expectancy for long-term exposure to fine particles, contributing to a better quantification of the impact of AP on PH in Europe.

Different effects of urban and rural environments in the respiratory status of Greek schoolchildren

We hypothesized that asthma symptoms and lung function of schoolchildren living in Athens urban area are adversely affected as compared to others living in a rural environment, over a period of 8 years. We recruited 478 and 342 children aged 8-10 years living within a short radius around the urban and rural area monitoring stations, respectively. Respiratory health was assessed by a parent-completed questionnaire in three phases: 1995-1996 (phase-1), 1999-2000 (phase-2), 2003-2004 (phase-3) and by spirometry in phases-1 and 2. Reported asthma and wheeze did not differ in the two areas, whereas cough was more prevalent in the urban area in phase-1. Children from the rural environment had lower levels of percent-predicted forced vital capacity (FVC%) in phase-1 and higher of percent-predicted-forced expiratory flow at mid-FVC (FEF(50)%) in both phases. Independent associations were detected between FVC% as-well-as FEF(50)% and residential area. High FVC% was associated with outdoor systemic athletic activities; there was lower FVC% growth in the urban versus the rural area. Nitrogen dioxide and sulfur dioxide were higher in the urban area, whereas ozone concentrations differed less between the two areas. These results suggest that long-term exposure to urban environment is associated with sub-clinical airway narrowing and slower rate of FVC growth.