Indoor environmental influences on children's asthma

Indoor Environmental Exposures and Their Relationship to Allergic Diseases

Cockroach, dust mite, cat, dog, mouse, and molds are major indoor allergens that have been associated with the development of allergic diseases and disease morbidity in allergen-sensitized individuals. Physical characteristics, such as allergen particle size, hydrophobicity, and charge, can determine an allergen's propensity to become airborne, location of respiratory tract penetration, and ability to elicit IgE responses in genetically predisposed individuals. Standardization and recent advancements in indoor allergen assessment serve to identify sources and distribution of allergens in a patient's home and public environment, inform public policy, and monitor the efficacy of allergen avoidance and therapeutics. Allergen exposure interventions have yielded mixed results with current US and international asthma guidelines differing on recommendations. A pragmatic, patient-centered approach to allergen avoidance includes: (1) tailoring intervention to the patient's sensitization and exposure status, (2) using a rigorous multifaceted intervention strategy to reduce allergen exposure as much as possible, and (3) beginning the intervention as soon as the patient is diagnosed. Further research into the risks/benefits of early allergen exposure, rapid and affordable in-home allergen assessment, and best practices for environmental control measures for asthma is needed.

Efficacy of indoor air purification in the treatment of Artemisia pollen-allergic rhinitis: A randomised, double-blind, clinical controlled trial

Objectives

To evaluate the clinical efficacy of a high‐efficiency air purifier in patients with allergic rhinitis.

Design

We conducted a randomised, double‐blind, clinical controlled trial with active and inactive versions of an air purifier. Our study included patients with allergic rhinitis who were sensitive to Artemisia pollen and treatment of the indoor environment using air filtration at night. We evaluated the clinical efficacy of indoor air filtration during the Artemisia pollen scattering season in Yulin City in Shanxi Province, China.

Setting

The First Hospital of Yulin (Yulin City, Shanxi Province, China).

Participants

A total of 90 patients with allergic rhinitis who were sensitive to allergens of Artemisia pollen were randomly assigned to one of two groups in equal numbers.

Main outcome measures

The primary outcome measure was the difference in visual analogue scale scores from baseline. Secondary outcomes were changes from baseline in nasal symptoms, allergy symptom scores, responses to the Rhinoconjunctivitis Quality of Life Questionnaire, Epworth Sleepiness Scale scores and tolerability scores for the air purifier.

Results

Based on the allergy symptom score, we found significant differences in rhinitis symptoms between the groups who used the active versus the inactive air purifier.

Conclusions

The results of our investigation demonstrated the health benefits of particle filtration.

Role of epidemiological risk factors in improving the clinical diagnosis of streptococcal sore throat in pediatric clinical practice

BACKGROUND AND AIMS

Antibiotics are frequently prescribed for sore throat in developing countries, that in turn leads to huge healthcare expenditure and their irrational use may lead to antimicrobial resistance in the community. The aim of this study is to investigate the effect of environmental factors on the frequency of occurrence of group A beta hemolytic streptococcus (GABHS) sore throat and to work out enhancing effect on the sensitivity and specificity and positive predictive value of the signs and symptoms of GABHS sore throat for facilitation of rational antibiotic use.

SETTINGS AND DESIGN

This was a prospective, cross sectional study conducted over period of one year in Pediatric Outpatient Department (OPD) of a Tertiary care teaching hospital.

METHODS

All the children between the age of 5 years and 15 years of age presenting in OPD with the signs and symptoms of sore throat were included in the study.

STATISTICAL ANALYSIS USED

Statistical analysis was carried out by using Statistical Package for Social Sciences software and statistical tests of Pearson's Coefficient, Chi-square Test, Fischer's Test, Likelihood Ratio, Odds Ratio, and ROC Curve were applied.

RESULTS

Out of 225 children of the study group, 153 (68%) of the children were in the 5-10 years' age group. Positive throat swab culture was found to be positively associated with high grade fever, pain in throat while swallowing, severely enlarged tonsils, tender lymphadenopathy, poor housing condition, fuel used for cooking, and presence of smoker in house.

CONCLUSIONS

The study stresses on the need of carefully evaluating children presenting with the symptoms of sore throat as majority of the cases may be viral and thus, self-limiting. Poor housing conditions and indoor pollution contribute to the increased prevalence of sore throat.

Environmental Air Pollutants as Risk Factors for Asthma Among Children Seen in Pediatric Clinics in UKMMC, Kuala Lumpur

The prevalence of asthma is increasing, especially among children in Malaysia, with environmental factors as one of the main preventable contributors. The aim of this study was to determine the association between environmental air pollutants and the occurrence of asthma among children seen in pediatric clinics in Universiti Kebangsaan Malaysia Medical Center (UKMMC), Kuala Lumpur. An unmatched case control study among children who attended the pediatric clinic was carried out from May to August 2015. A total of 223 children who were diagnosed with asthma (105 cases) and who did not have asthma (118 controls) were included in this study. Their parents or caregivers were interviewed using questionnaires modified from the International Study of Asthma and Allergies in Childhood. Data obtained were analyzed using SPSS software version 20. There was a higher risk of asthma in those who had carpet at home (OR = 2.15 CI [1.25-3.68]), those who lived within 200 m of heavy traffic (OR = 1.72 CI [1.01-2.93]), and those who were exposed to lorry fumes (OR = 2.61. CI [1.38-4.93]). Environmental air pollutants increased the risk of asthma among children in Malaysia. Exposure to congested roads, lorry fumes, and indoor carpet were associated with asthma among children in this study. Parents or caretakers of children with asthma should be given adequate education on the prevention of asthmatic attack among these children.

Prevalence of asthma and associated factors among male late adolescents in Tabriz, Iran

Asthma is an important chronic disease all over the world. The aim of this study was to determine the prevalence of asthma in a population of male late adolescents and its association with some contributing risk factors in northwest of Iran. This cross-sectional study was carried out in selected high schools of Tabriz, Iran, in 2016. The asthma prevalence and patient background information were examined using a questionnaire that prepared by the ISAAC. One hundred forty-two out of 1134 subjects (12.4%) identified to have asthma, 23.3% had history of current wheeze, and 16.3% had wheezing in the previous year. Family history of asthma was present in 17.1% of the participants; prevalence of active smoking in the study subjects was 3.1%; 25.1% of all subjects had exposure to secondhand tobacco smoke and keeping pets at home was present in 9.1%. Excess weight (overweight and obesity) was positively associated with prevalence of asthma (p < 0.001). No statistically significant associations were observed between asthma and father's education level (p = 0.570), mother's education level (p = 0.584), type of birth subjects (p = 0.571), and time spent outdoors during a full day (p = 0.863). Our results suggest that family history of asthma and atopy, exposure to secondhand tobacco smoke, active smoking, amount of automobile traffic around subjects' home, and keeping pets at homes are important risk factors for asthma, while time spent outdoors, educations of parents, and delivery type (normal vaginal delivery vs. C-section) subjects are not. Therefore, decreased of exposure to some environmental risk factors could be effective to reduce rate of the prevalence of asthma and wheeze.

Impacting Environmental and Public Health through the Use of Dual Targeted and Tailored Asthma Educational Interventions

Home-based asthma environmental education for parents of asthmatic children is needed since many health professionals lack the time to offer it. However, developing targeted and tailored education is important in order to address the individual needs of participants. This nonrandomized longitudinal study examined knowledge on asthma with an Asthma and Healthy Homes educational intervention training offered to parents of children from low income families who reside in the Rio Grande Valley of Texas. Eighty-nine parents received the training and pre- and posttest surveys were used to measure knowledge outcomes. A standardized assessment on asthma triggers was used to identify the different triggers each child was exposed to, and a follow-up survey was conducted 6 months after the educational intervention to identify how many parents reported household and behavior changes as a result of the training. Results showed significant changes in behavior by participants as a result of the training received. This study suggests that these behavioral changes are attributed to the dual "targeted" and "tailored" educational interventions delivered to parents which resulted in a greater understanding of how to manage asthma by eliminating asthma triggers in their respective homes.

Meta-Analytic Approaches for Multistressor Dose-Response Function Development: Strengths, Limitations, and Case Studies

For many policy analyses, including but not limited to cumulative risk assessments, it is important to characterize the individual and joint health effects of multiple stressors. With an increasing focus on psychosocial and other nonchemical stressors, this often includes epidemiological meta-analysis. Meta-analysis has limitations if epidemiological studies do not include all of the stressors of interest or do not provide multivariable outputs in a format necessary for risk assessment. Given these limitations, novel analytical methods are often needed to synthesize the published literature or to build upon available evidence. In this article, we discuss three recent case studies that highlight the strengths and limitations of meta-analytic approaches and other research synthesis techniques for human health risk assessment applications. First, a literature-based meta-analysis within a risk assessment context informed the design of a new epidemiological investigation of the differential toxicity of fine particulate matter constituents. Second, a literature synthesis for an effects-based cumulative risk assessment of hypertension risk factors led to a decision to develop new epidemiological associations using structural equation modeling. Third, discrete event simulation modeling was used to simulate the impact of changes in the built environment on environmental exposures and associated asthma outcomes, linking literature meta-analyses for key associations with a simulation model to synthesize all of the model components. These case studies emphasize the importance of conducting epidemiology with a risk assessment application in mind, the need for interdisciplinary collaboration, and the value of advanced analytical methods to synthesize epidemiological and other evidence for risk assessment applications.

Meta-analysis of the effects of indoor nitrogen dioxide and gas cooking on asthma and wheeze in children

BACKGROUND

Since the meta-analysis on the association between indoor nitrogen dioxide (NO2) and childhood respiratory illness in 1992, many new studies have been published. The quantitative effects of indoor NO2 on respiratory illness have not been estimated in a formal meta-analysis since then. We aimed to quantify the association of indoor NO2 and its main source (gas cooking) with childhood asthma and wheeze.

METHODS

We extracted the association between indoor NO2 (and gas cooking) and childhood asthma and wheeze from population studies published up to 31 March 2013. Data were analysed by inverse-variance-weighted, random-effects meta-analysis. Sensitivity analyses were conducted for different strata. Publication bias and heterogeneity between studies were investigated.

RESULTS

A total of 41 studies met the inclusion criteria. The summary odds ratio from random effects meta-analysis for asthma and gas cooking exposure was 1.32 [95% confidential interval (CI) 1.18-1.48], and for a 15-ppb increase in NO2 it was 1.09 (95% CI 0.91-1.31). Indoor NO2 was associated with current wheeze (random effects OR 1.15; 95% CI 1.06-1.25). The estimates did not vary much with age or between regions. There was no evidence of publication bias.

CONCLUSIONS

This meta-analysis provides quantitative evidence that, in children, gas cooking increases the risk of asthma and indoor NO2 increases the risk of current wheeze.

Improvement of atopic dermatitis severity after reducing indoor air pollutants

Background

Recent epidemiologic studies have shown that environmental contaminants such as air pollution and tobacco smoke play an important role in the pathophysiology of atopic dermatitis (AD).

Objective

The aim of this study was to evaluate the relationship between the severity of AD and indoor air pollution.

Methods

The study population consisted of 425 children from 9 kindergartens, Korea. The authors surveyed the prevalence of AD and evaluated disease severity by the eczema area and severity index (EASI) score and investigator's global assessment (IGA). After measuring indoor air pollution, a program to improve indoor air quality was conducted in 9 kindergartens. Seven months later, the prevalence and disease severity were evaluated.

Results

The initial prevalence of AD was 8% and the mean EASI score was 2.37. The levels of particulate material 10 (PM₁₀) and carbon dioxide (CO₂) were higher in some kindergartens compared to the normal values. Subsequent to the completion of the indoor air quality improvement program, the mean PM₁₀ level was significantly decreased from 182.7 to 73.4 µg/m³. After the completion of the program, the prevalence of AD and the mean EASI were decreased, and the changes were both statistically significant. The mean number of hospital visits decreased from 1.3 per month during the first survey to 0.7 per month during the second survey, which was statistically significant.

Conclusion

Indoor air pollution could be related to AD. The reduction of PM₁₀ through improving indoor air quality should be considered in kindergartens and schools in order to prevent and relieve AD in children.

A simulation model of building intervention impacts on indoor environmental quality, pediatric asthma, and costs

BACKGROUND

Although indoor environmental conditions can affect pediatric asthmatic patients, few studies have characterized the effect of building interventions on asthma-related outcomes. Simulation models can evaluate such complex systems but have not been applied in this context.

OBJECTIVE

We sought to evaluate the impact of building interventions on indoor environmental quality and pediatric asthma health care use, and to conduct cost comparisons between intervention and health care costs and energy savings.

METHODS

We applied our previously developed discrete event simulation model (DEM) to simulate the effect of environmental factors, medication compliance, seasonality, and medical history on (1) pollutant concentrations indoors and (2) asthma outcomes in low-income multifamily housing. We estimated health care use and costs at baseline and subsequent to interventions, and then compared health care costs with energy savings and intervention costs.

RESULTS

Interventions, such as integrated pest management and repairing kitchen exhaust fans, led to 7% to 12% reductions in serious asthma events with 1- to 3-year payback periods. Weatherization efforts targeted solely toward tightening a building envelope led to 20% more serious asthma events, but bundling with repairing kitchen exhaust fans and eliminating indoor sources (eg, gas stoves or smokers) mitigated this effect.

CONCLUSION

Our pediatric asthma model provides a tool to prioritize individual and bundled building interventions based on their effects on health and costs, highlighting the tradeoffs between weatherization, indoor air quality, and health. Our work bridges the gap between clinical and environmental health sciences by increasing physicians' understanding of the effect that home environmental changes can have on their patients' asthma.

Household levels of nitrogen dioxide and pediatric asthma severity

BACKGROUND

Adverse respiratory effects in children with asthma are associated with exposures to nitrogen dioxide (NO2). Levels indoors can be much higher than outdoors. Primary indoor sources of NO2 are gas stoves, which are used for cooking by one-third of U.S. households. We investigated the effects of indoor NO2 exposure on asthma severity among an ethnically and economically diverse sample of children, controlling for season and indoor allergen exposure.

METHODS

Children 5-10 years of age with active asthma (n = 1,342) were recruited through schools in urban and suburban Connecticut and Massachusetts (2006-2009) for a prospective, year-long study with seasonal measurements of NO2 and asthma severity. Exposure to NO2 was measured passively for four, month-long, periods with Palmes tubes. Asthma morbidity was concurrently measured by a severity score and frequency of wheeze, night symptoms, and use of rescue medication. We used adjusted, hierarchical ordered logistic regression models to examine associations between household NO2 exposure and health outcomes.

RESULTS

Every 5-fold increase in NO2 exposure above a threshold of 6 ppb was associated with a dose-dependent increase in risk of higher asthma severity score (odds ratio = 1.37 [95% confidence interval = 1.01-1.89]), wheeze (1.49 [1.09-2.03]), night symptoms (1.52 [1.16-2.00]), and rescue medication use (1.78 [1.33-2.38]).

CONCLUSIONS

Asthmatic children exposed to NO2 indoors, at levels well below the U.S. Environmental Protection Agency outdoor standard (53 ppb), are at risk for increased asthma morbidity. Risks are not confined to inner city children, but occur at NO2 concentrations common in urban and suburban homes.

The effects of indoor environmental exposures on pediatric asthma: a discrete event simulation model

BACKGROUND

In the United States, asthma is the most common chronic disease of childhood across all socioeconomic classes and is the most frequent cause of hospitalization among children. Asthma exacerbations have been associated with exposure to residential indoor environmental stressors such as allergens and air pollutants as well as numerous additional factors. Simulation modeling is a valuable tool that can be used to evaluate interventions for complex multifactorial diseases such as asthma but in spite of its flexibility and applicability, modeling applications in either environmental exposures or asthma have been limited to date.

METHODS

We designed a discrete event simulation model to study the effect of environmental factors on asthma exacerbations in school-age children living in low-income multi-family housing. Model outcomes include asthma symptoms, medication use, hospitalizations, and emergency room visits. Environmental factors were linked to percent predicted forced expiratory volume in 1 second (FEV1%), which in turn was linked to risk equations for each outcome. Exposures affecting FEV1% included indoor and outdoor sources of NO2 and PM2.5, cockroach allergen, and dampness as a proxy for mold.

RESULTS

Model design parameters and equations are described in detail. We evaluated the model by simulating 50,000 children over 10 years and showed that pollutant concentrations and health outcome rates are comparable to values reported in the literature. In an application example, we simulated what would happen if the kitchen and bathroom exhaust fans were improved for the entire cohort, and showed reductions in pollutant concentrations and healthcare utilization rates.

CONCLUSIONS

We describe the design and evaluation of a discrete event simulation model of pediatric asthma for children living in low-income multi-family housing. Our model simulates the effect of environmental factors (combustion pollutants and allergens), medication compliance, seasonality, and medical history on asthma outcomes (symptom-days, medication use, hospitalizations, and emergency room visits). The model can be used to evaluate building interventions and green building construction practices on pollutant concentrations, energy savings, and asthma healthcare utilization costs, and demonstrates the value of a simulation approach for studying complex diseases such as asthma.

Enhancing ventilation in homes of children with asthma: pragmatic randomised controlled trial

BACKGROUND

Few robust studies have tested whether enhancing housing also improves health.

AIM

To evaluate the effectiveness of installing ventilation systems, and central heating where necessary, in the homes of children with moderate or severe asthma.

DESIGN AND SETTING

Pragmatic randomised controlled trial (RCT) in homes within Wrexham County Borough, Wales, UK.

METHOD

A pragmatic RCT was carried out, of a tailored package of housing improvements providing adequate ventilation and temperature, following inspection by a housing officer. One hundred and ninety-two children with asthma aged 5 to 14 years, identified from general practice registers, were randomised to receive this package, either immediately or a year after recruitment. At baseline, and after 4 and 12 months, parents reported their child's asthma-specific and generic quality of life, and days off school.

RESULTS

The package improved parent-reported asthma-specific quality of life significantly at both 4 and 12 months. At 12 months, this showed an adjusted mean difference between groups of 7.1 points (95% confidence interval [CI] = 2.8 to 11.4, P= 0.001): a moderate standardised effect size of 0.42. The generic quality-of-life scale showed reported physical problems were significantly reduced at 4 months, but not quite at 12 months, when the mean difference was 4.5 (95% CI = -0.2 to 9.1, P= 0.061). The improvement in psychosocial quality of life at 12 months was not significant, with a mean difference of 2.2 (95% CI = -1.9 to 6.4, P= 0.292). Parent-reported school attendance improved, but not significantly.

CONCLUSION

This novel and pragmatic trial, with integrated economic evaluation, found that tailored improvement of the housing of children with moderate to severe asthma significantly increases parent-reported asthma-related quality of life and reduces physical problems. Collaborative housing initiatives have potential to improve health.

Simulating indoor concentrations of NO(2) and PM(2.5) in multifamily housing for use in health-based intervention modeling

Residents of low-income multifamily housing can have elevated exposures to multiple environmental pollutants known to influence asthma. Simulation models can characterize the health implications of changing indoor concentrations, but quantifying the influence of interventions on concentrations is challenging given complex airflow and source characteristics. In this study, we simulated concentrations in a prototype multifamily building using CONTAM, a multizone airflow and contaminant transport program. Contaminants modeled included PM(2.5) and NO(2) , and parameters included stove use, presence and operability of exhaust fans, smoking, unit level, and building leakiness. We developed regression models to explain variability in CONTAM outputs for individual sources, in a manner that could be utilized in simulation modeling of health outcomes. To evaluate our models, we generated a database of 1000 simulated households with characteristics consistent with Boston public housing developments and residents and compared the predicted levels of NO(2) and PM(2.5) and their correlates with the literature. Our analyses demonstrated that CONTAM outputs could be readily explained by available parameters (R(2) between 0.89 and 0.98 across models), but that one-compartment box models would mischaracterize concentrations and source contributions. Our study quantifies the key drivers for indoor concentrations in multifamily housing and helps to identify opportunities for interventions.

PRACTICAL IMPLICATIONS

Many low-income urban asthmatics live in multifamily housing that may be amenable to ventilation-related interventions such as weatherization or air sealing, wall and ceiling hole repairs, and exhaust fan installation or repair, but such interventions must be designed carefully given their cost and their offsetting effects on energy savings as well as indoor and outdoor pollutants. We developed models to take into account the complex behavior of airflow patterns in multifamily buildings, which can be used to identify and evaluate environmental and non-environmental interventions targeting indoor air pollutants which can trigger asthma exacerbations.

Paternal heredity and housing characteristics affect childhood asthma and allergy morbidity

A birth cohort was initiated when each pregnant woman was asked for her own and her husband's history of asthma and allergic diseases at the time of recruitment. They were further inquired to verify their housing conditions, and current health status of children 3 to 5 years old at the time of interview. Paternal history was the most significant risk factor associated with reporting childhood morbidities at age of 3 to 5 years. Housing characteristics became meaningful variables only if the fathers were asthmatic or atopic. A 9-fold increase of risk was found if children with paternal history and also exposed to incense burning and water damage at home. This is the first epidemiological evidence of East Asia suggesting paternal heredity, with concurrent indoor hazardous exposures, as a predominant risk on developing childhood asthma and allergy.

The Breathe-Easy Home: the impact of asthma-friendly home construction on clinical outcomes and trigger exposure

OBJECTIVES

We examined the asthma-control benefit of moving into an asthma-friendly Breathe-Easy home (BEH).

METHODS

We used a quasi-experimental design to compare the asthma outcomes of 2 groups of low-income children and adolescents with asthma: 34 participants who moved into a BEH, and a local matched cohort of 68 participants who had received a previous asthma-control intervention. Both groups received in-home asthma education. BEHs were constructed with moisture-reduction features, enhanced ventilation systems, and materials that minimized dust and off-gassing.

RESULTS

BEH residents' asthma-symptom-free days increased from a mean of 8.6 per 2 weeks in their old home to 12.4 after 1 year in the BEH. The proportion of BEH residents with an urgent asthma-related clinical visit in the previous 3 months decreased from 62% to 21%. BEH caretakers' quality of life increased significantly. The BEH group improved more than did the comparison group, but most differences in improvements were not significant. Exposures to mold, rodents, and moisture were reduced significantly in BEHs.

CONCLUSIONS

Children and adolescents with asthma who moved into an asthma-friendly home experienced large decreases in asthma morbidity and trigger exposure.

The impact of school building conditions on student absenteeism in Upstate New York

OBJECTIVES

We investigated Upstate New York school building conditions and examined the associations between school absenteeism and building condition problems.

METHODS

We merged data from the 2005 Building Condition Survey of Upstate New York schools with 2005 New York State Education Department student absenteeism data at the individual school level and evaluated associations between building conditions and absenteeism at or above the 90th percentile.

RESULTS

After adjustment for confounders, student absenteeism was associated with visible mold (odds ratio [OR]=2.22; 95% confidence interval [CI]=1.34, 3.68), humidity (OR=3.07; 95% CI=1.37, 6.89), poor ventilation (OR=3.10; 95% CI=1.79, 5.37), vermin (OR=2.23; 95% CI=1.32, 3.76), 6 or more individual building condition problems (OR=2.97; 95% CI=1.84, 4.79), and building system or structural problems related to these conditions. Schools in lower socioeconomic districts and schools attended by younger students showed the strongest associations between poor building conditions and absenteeism.

CONCLUSIONS

We found associations between student absenteeism and adverse school building conditions. Future studies should confirm these findings and prioritize strategies for school condition improvements.

Home environmental factors associated with poor asthma control in Montreal children: a population-based study

BACKGROUND

Home environmental exposures may aggravate asthma. Few population-based studies have investigated the relationship between asthma control in children and home environmental exposures.

OBJECTIVE

Identify home environmental exposures associated with poor control of asthma among asthmatic children less than 12 years of age in Montreal (Quebec, Canada).

METHODS

This cross-sectional population-based study used data from a respiratory health survey of Montreal children aged 6 months to 12 years conducted in 2006 (n = 7980). Asthma control was assessed (n = 980) using an adaptation of the Canadian asthma consensus report clinical parameters. Using log-binomial regression models, prevalence ratios (PRs) with 95% confidence intervals (95% CIs) were estimated to explore the relationship between inadequate control of asthma and environmental home exposures, including allergens, irritants, mold, and dampness indicators. Subjects with acceptable asthma control were compared with those with inadequate disease control.

RESULTS

Of 980 children with active asthma in the year prior to the survey, 36% met at least one of the five criteria as to poor control of their disease. The population's characteristics found to be related with a lack of asthma control were younger age, history of parental atopy, low maternal education level, foreign-born mothers, and tenant occupancy. After adjustments, children living along high-traffic density streets (PR, 1.35; 95% CI, 1.00-1.81) and those with their bedroom or residence at the basement level (PR, 1.30; 95% CI, 1.01-1.66) were found to be at increased risk of poor asthma control.

CONCLUSIONS

Suboptimal asthma control appears to be mostly associated with traffic, along with mold and moisture conditions, the latter being a more frequent exposure and therefore having a greater public health impact.

Indoor exposure to environmental cigarette smoke, but not other inhaled particulates associates with respiratory symptoms and diminished lung function in adults

BACKGROUND AND OBJECTIVE

Exposure to particulate matter (PM) can induce airway inflammation and exacerbation of asthma. However, there is limited knowledge about the effects of exposure to indoor sources of PM. We investigated the associations between self-reported exposure to indoor sources of PM and lower airway symptoms and lung function.

METHODS

A population-based cross-sectional study of 3471 persons aged 18-69 years was conducted. Information about exposure to indoor sources of PM and airway symptoms was obtained from a self-administered questionnaire.

RESULTS

Exposure to wood stoves, candles and gas cookers was not significantly associated with an increased prevalence of lower respiratory symptoms or decreased lung function. In contrast, persons exposed to environmental tobacco smoke for >5 h/day had a significantly increased risk of 'wheeze' (OR 1.69, 95% CI: 1.24-2.30) and 'chronic cough' (OR 1.57, 95% CI: 1.12-2.20), as well as decreased lung function (FEV(1)% predicted), compared with those who were not exposed. Similar trends were observed in never smokers.

CONCLUSIONS

In this cross-sectional study of an adult general population, self-reported exposure to environmental tobacco smoke, but not self-reported exposure to wood stoves, candles or gas cookers, appeared to be associated with an increased prevalence of lower airway symptoms and decreased lung function.

Environmental and occupational allergies

Airborne allergens are the major cause of allergic rhinitis and asthma. Daily exposure comes from indoor sources, chiefly at home but occasionally at schools or offices. Seasonal exposure to outdoor allergens, pollens, and molds is another important source. Exposure to unusual substances at work causes occupational asthma, accounting for about 5% of asthma in adults. Indoor and outdoor air pollutants trigger airway inflammation and increase the severity of asthma. Diesel exhaust particles increase the production of IgE antibodies. Identification and reduction of exposure to allergens is a very important part of the management of respiratory allergic diseases. The first section of this chapter discusses domestic allergens, arthropods (mites and cockroaches), molds, and mammals (pets and mice). Indoor humidity and water damage are important factors in the production of mite and mold allergens, and discarded human food items are important sources of proliferation of cockroaches and mice. Means of identifying and reducing exposure are presented. The second section discusses outdoor allergens: pollens and molds. The particular plants or molds and the amount of exposure to these allergens is determined by the local climate, and local pollen and mold counts are available to determine the time and amount of exposure. Climate change is already having an important effect on the distribution and amount of outdoor allergens. The third section discusses indoor and outdoor air pollution and methods that individuals can take to reduce indoor pollution in addition to eliminating cigarette smoking. The fourth section discusses the diagnosis and management of occupational asthma.

Pest and allergen exposure and abatement in inner-city asthma: a work group report of the American Academy of Allergy, Asthma & Immunology Indoor Allergy/Air Pollution Committee

Our work group report details the importance of pest allergen exposure in inner-city asthma. We will focus specifically on mouse and cockroach exposure. We will discuss how exposure to these pests is common in the inner city and what conditions exist in urban areas that might lead to increased exposure. We will discuss how exposure is associated with allergen sensitization and asthma morbidity. Finally, we will discuss different methods of intervention and the effectiveness of these tactics.

Recent findings on the pathogenesis of bronchial asthma. Part II. The role of hormonal predisposition, environmental influences and conditioning leading to bronchial asthma

In this second part of the review on the pathogenesis of asthma the hormonal factors and adverse external events are shortly reviewed which skew the balance of Th1 vs. Th2 CD4+ lymphocytes towards the latter ones and this way increase the probability of atopic diseases. Among other the role of transplacental priming, insulin, insulin-like and other growth factors, lack of the usual microbial infections in the early childhood (the so-called hygiene hypothesis), gender, diminished testosterone production, gastroesophageal reflux, adverse effects during pregnancy are discussed. A separate chapter deals with the role of central nervous system in the etiology and finally the most common allergizing and airway tissue damaging agents are listed in tabulated form.

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.

Gene-environment interactions and airway disease in children

Asthma is the most common chronic disease of childhood in the United States, affecting nearly 6.5 million children. The prevalence and severity of childhood asthma have continued to increase over the past 2 decades, despite major advances in the recognition and treatment of this condition. Representing a heterogeneous collection of airway diseases, asthma has multiple pathologic processes resulting from the interactions of genetic susceptibility and environmental exposures. Preventing and treating airway disease in children will require new research approaches to understanding these complex interactions.

Early-life environment, developmental immunotoxicology, and the risk of pediatric allergic disease including asthma

Incidence of childhood allergic disease including asthma (AD-A) has risen since the mid-20th century with much of the increase linked to changes in environment affecting the immune system. Childhood allergy is an early life disease where predisposing environmental exposures, sensitization, and onset of symptoms all occur before adulthood. Predisposition toward allergic disease (AD) is among the constellation of adverse outcomes following developmental immunotoxicity (DIT; problematic exposure of the developing immune system to xenobiotics and physical environmental factors). Because novel immune maturation events occur in early life, and the pregnancy state itself imposes certain restrictions on immune functional development, the period from mid-gestation until 2 years after birth is one of particular concern relative to DIT and AD-A. Several prenatal-perinatal risk factors have been identified as contributing to a DIT-mediated immune dysfunction and increased risk of AD. These include maternal smoking, environmental tobacco smoke, diesel exhaust and traffic-related particles, heavy metals, antibiotics, environmental estrogens and other endocrine disruptors, and alcohol. Diet and microbial exposure also significantly influence immune maturation and risk of allergy. This review considers (1) the critical developmental windows of vulnerability for the immune system that appear to be targets for risk of AD, (2) a model in which the immune system of the DIT-affected infant exhibits immune dysfunction skewed toward AD, and (3) the lack of allergy-relevant safety testing of drugs and chemicals that could identify DIT hazards and minimize problematic exposure of pregnant women and children.

Classroom aeroallergen exposure in Arkansas head start centers

BACKGROUND

The impact of preschool environmental conditions on classroom aeroallergen concentrations is not fully understood.

OBJECTIVE

To examine the relationship between school environmental conditions and classroom aeroallergen concentrations in the Pulaski County Head Start (HS) Program.

METHODS

Thirty-three HS centers in Pulaski County, Arkansas, underwent a detailed environmental evaluation. Classroom settled dust samples were analyzed for the presence of common indoor allergens.

RESULTS

Classroom eating (70%), wall-to-wall carpeting (58%), and water damage (33%) were common. Median classroom allergen levels were as follows: dust mite (Der p 1 and Der f 1), 0.6 microg/g; Fel d 1, 0.4 microg/g; Can f 1, 1.7 microg/g; cockroach, below detection; Mus m 1, 0.18 microg/g; and mold spores, 17,800 CFU/g. Can f 1 and Mus m 1 allergens were detected in 100% of HS centers. Facilities with carpeting, increased humidity, and single-use facilities showed trends toward increased dust mite concentrations. Detectable cockroach allergen was more common in classrooms cleaned by teachers than by professional housekeepers.

CONCLUSIONS

Aeroallergens were commonly detected in Pulaski County HS center classrooms, with dog and mouse allergens detected in 100% of centers. Median classroom allergen concentrations were low, and classroom characteristics were not strongly predictive of increased allergen exposure.