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

The impact of indoor pollution on asthma-related outcomes: A systematic review for the EAACI guidelines on environmental science for allergic diseases and asthma

Systematic review using GRADE of the impact of exposure to volatile organic compounds (VOCs), cleaning agents, mould/damp, pesticides on the risk of (i) new-onset asthma (incidence) and (ii) adverse asthma-related outcomes (impact). MEDLINE, EMBASE and Web of Science were searched for indoor pollutant exposure studies reporting on new-onset asthma and critical and important asthma-related outcomes. Ninety four studies were included: 11 for VOCs (7 for incidenceand 4 for impact), 25 for cleaning agents (7 for incidenceand 8 for impact), 48 for damp/mould (26 for incidence and 22 for impact) and 10 for pesticides (8 for incidence and 2 for impact). Exposure to damp/mould increases the risk of new-onset wheeze (moderate certainty evidence). Exposure to cleaning agents may be associated with a higher risk of new-onset asthma and with asthma severity (low level of certainty). Exposure to pesticides and VOCs may increase the risk of new-onset asthma (very low certainty evidence). The impact on asthma-related outcomes of all major indoor pollutants is uncertain. As the level of certainty is low or very low for most of the available evidence on the impact of indoor pollutants on asthma-related outcomes more rigorous research in the field is warranted.

Environmental Exposure and Pediatric Asthma Prevalence in Saudi Arabia: A Cross-Sectional Study

INTRODUCTION

Asthma is a chronic respiratory disease characterized by recurrent episodes of wheezing and shortness of breath. Currently, there is no cure for asthma. However, through accurate diagnosis, appropriate therapy, and effective management strategies, individuals with asthma can achieve a better quality of life. This study focused on determining the prevalence and environmental risk factors of pediatric asthma among children in Saudi Arabia.

METHODS

This cross-sectional study was undertaken from January 2023 to August 2023, encompassing five key regions in Saudi Arabia: Central, Eastern, Northern, Southern, and Western. A structured online questionnaire was disseminated to parents/guardians of children aged 2-18 with a confirmed diagnosis of asthma. The objective was to garner insights regarding pediatric asthma prevalence and associated risk factors within these regions. The questionnaire was designed with considerations for sociodemographic factors, environmental exposures, and known asthma triggers. From the survey's distribution, a total of 1666 responses were accumulated and processed for further analysis.

RESULTS

The survey saw the participation of 1666 respondents. The age bracket of 8-13 years had the highest representation, accounting for 52.5% of the total participants. From the total cohort, 26.9% had been diagnosed with pediatric asthma. It was also observed that 56.7% of the participants resided in areas marked by high traffic or were proximate to busy roads. Additionally, 30.7% of the respondents pinpointed specific times in the year when asthma symptoms intensified. When dissecting the data, it was discerned that there were statistically significant associations between the prevalence of pediatric asthma, gender, and the regions of Saudi Arabia with reference to air pollution exposure. Notably, gender had an odds ratio of 1.12, while the regional distribution held an odds ratio of 1.

CONCLUSION

Our study vividly highlights the intricate landscape of pediatric asthma across Saudi Arabia, indicating its prevalence and drawing attention to associated risk factors. Noteworthy observations include the pronounced impact of gender and regional variances, particularly concerning air pollution exposure, on asthma incidence. The insights gleaned from this research are invaluable in steering the formulation and implementation of strategic interventions geared towards bolstering children's health and enhancing their life quality in regions bearing the brunt of pediatric asthma.

Allergen Management in Children with Type 2-High Asthma

Children exposed to various indoor and outdoor allergens are placed at an increased risk of developing asthma in later life, with sensitization in these individuals being a strong predictor of disease morbidity. In addition, aeroallergen exposure influences asthma outcomes through an interplay with adverse determinants of health. The goal of this review is to provide an introductory overview of factors related to aeroallergen exposure in type 2-high childhood asthma. These include the relevance of exposure in asthma exacerbations and severity, and the evidence-base for avoidance and treatment for sensitization to these allergens. This review will focus on both indoor aeroallergens (house dust mite, pet, cockroach, mold, and rodent) and outdoor aeroallergens (pollens and molds). Treatment of aeroallergen sensitization in children with asthma includes avoidance and removal measures, although there is limited evidence of clinical benefit especially with single-strategy approaches. We will also address the interplay of aeroallergens and climate change, adverse social determinants, and the current COVID-19 pandemic, when we have seen a dramatic reduction in asthma exacerbations and emergency department visits among children. While there are many factors that are hypothesized to contribute to this reduction, among them is a reduced exposure to outdoor seasonal aeroallergens.

Indoor Environmental Interventions for Furry Pet Allergens, Pest Allergens, and Mold: Looking to the Future

Over the last 2 to 3 decades, significant advances have been made in understanding the role that indoor allergen exposures play with regard to respiratory health. Multiple studies have confirmed that sensitization and exposure to indoor allergens can be a risk factor for asthma morbidity. Environmental interventions targeting key indoor allergens have been evaluated with the aims of examining their causal effects on asthma-related outcomes and identifying clinically efficacious interventions to incorporate into treatment recommendations. Historically, it appeared that the most successful intervention, as performed in the Inner-City Asthma Study, was individually tailored, targeting multiple allergens in a predominantly low-income, minority, and urban pediatric population. Recent studies suggest that single-allergen interventions may be efficacious when targeting the most clinically relevant allergen for a population. In this article, we review recent literature on home environmental interventions and their effects on specific indoor allergen levels and asthma-related outcomes.

Inner-City Asthma in Children

Asthma in inner-city children is often severe and difficult to control. Residence in poor and urban areas confers increased asthma morbidity even after adjusting for ethnicity, age, and gender. Higher exposure to household pests, such as cockroaches and mice, pollutants and tobacco smoke exposure, poverty, material hardship, poor-quality housing, differences in health care quality, medication compliance, and heath care access also contribute to increased asthma morbidity in this population. Since 1991, the National Institutes of Allergy and Infectious Diseases established research networks: the National Cooperative Inner-City Asthma Study (NCICAS), the Inner-City Asthma Study (ICAS), and the Inner-City Asthma Consortium (ICAC), to improve care for this at risk population. The most striking finding of the NCICAS is the link between asthma morbidity and the high incidence of allergen sensitization and exposure, particularly cockroach. The follow-up ICAS confirmed that reductions in household cockroach and dust mite were associated with reduction in the inner-city asthma morbidity. The ICAC studies have identified that omalizumab lowered fall inner-city asthma exacerbation rate; however, the relationship between inner-city asthma vs immune system dysfunction, respiratory tract infections, prenatal environment, and inner-city environment is still being investigated. Although challenging, certain interventions for inner-city asthma children have shown promising results. These interventions include family-based interventions such as partnering families with asthma-trained social workers, providing guidelines driven asthma care as well as assured access to controller medication, home-based interventions aim at elimination of indoor allergens and tobacco smoke exposure, school-based asthma programs, and computer/web-based asthma programs.

Indoors and health: results of a systematic literature review assessing the potential health effects of living in basements

A new law approved in March 2017 in the Lombardy Region makes it possible to live in basements. Basements are defined as buildings partly below curb level but with at least one-half of its height above the curb. Basements' features and structural characteristics might pose risks to human health. In this paper we adopt a multidisciplinary approach to assess the potential health effects of living in basements. In particular, we define a conceptual framework to describe basements' structural characteristics which are risk factors, as well as the mechanisms through which they impact on human health. We also conduct a systematic review on the scientific databases PubMed,Embase, DOAJ, Proquest and EBSCO to retrieve, pool and critically analyze all available research that quantified the risk of living in basements for different health outcomes. Available evidence suggests living in basements increases the risk of respiratory diseases (asthma and allergic disorders); more heterogeneous data are available for cancers and cardiovascular diseases. As more quantitative data need to be prospectively retrieved to assess and monitor the risk of living in basements for human health, clear minimum requirements for light, air, sanitation and egress are to be defined by technical experts and enforced by policy makers.

Environmental Determinants of Bronchial Asthma among Saudi School Children in Southwestern Saudi Arabia

The aim here was to study the possible environmental and dietary determinants of asthma among school-aged children in Southwestern Saudi Arabia. In a cross-sectional study on a representative sample in Najran in Southwestern Saudi Arabia using an Arabic version of the modified ISAAC Phase III, parent-administered questionnaire data were collected. Skin prick tests (SPTs) were performed. The study included 1700 school children, out of them 468 (27.5%) were diagnosed with, cases of bronchial asthma and 20.8% (353) reported a 12-month nocturnal cough (as a proxy of severe asthma). In multivariable analysis, the study identified the following risk factors for having asthma or severe asthma: having dogs in the house, being male, being exposed to dense truck traffic on the street, using wood as a cooking fuel, conducting vigorous exercise, consuming eggs, consuming vegetables, having an allergic sensitization to dog hair, and being exposed to Cladosporium, pigweed, and Bermuda grass. On the other hand, the following food stuffs were found to be protective: seafood, fruit, and dairy products. Comprehensive school educational programs for both children and their parents should be adopted to prevent the use of wood in cooking and heating, to ensure that house pets are properly cared for, and to encourage proper dietary habits. Physicians should be informed of the patterns of allergens in order to improve asthma diagnosis and management.

Determinants of longitudinal health-related quality-of-life change in children with asthma from low-income families: a report from the PROMIS® Pediatric Asthma Study

BACKGROUND

How the longitudinal asthma control status and other socio-demographic factors influence the changes of health-related quality of life (HRQOL) among asthmatic children, especially from low-income families, has not been fully investigated.

OBJECTIVES

This study aimed to describe the trajectories of asthma-specific HRQOL over 15 months and examine the effect of asthma control status on HRQOL by taking socio-demographic factors into consideration.

METHODS

A total of 229 dyads of asthmatic children and their parents enroled in public insurance programs were recruited for assessing asthma control status and HRQOL over four time points of assessment. Asthma control status was measured using the Asthma Control and Communication Instrument, and asthma-specific HRQOL was assessed using the Patient-Reported Outcomes Measurement Information System's Pediatric Asthma Impact Scale. Latent growth models (LGMs) were applied to examine the trajectory of HRQOL and the factors contributing to the changes of HRQOL.

RESULTS

Unconditional LGM revealed that HRQOL was improved over time. Conditional LGM suggested that accounting for asthma control and participants' socio-demographic factors, the variation in the initial level of HRQOL was significant, yet the rate of change was not. Conditional LGM also revealed that poorly controlled asthma status was associated with poor HRQOL at each time point (P's < 0.05). Lower parental education was associated with lower baseline HRQOL (P < 0.05). Hispanic children had a larger increase in HRQOL over time (P < 0.01) than non-Hispanic White children.

CONCLUSIONS

Vulnerable socio-demographic characteristics and poorly controlled asthma status affect HRQOL in children. This finding encourages interventions to improve asthma control status and HRQOL in minority children.

Severe and Moderate Asthma Exacerbations in Asthmatic Children and Exposure to Ambient Air Pollutants

BACKGROUND

It is well established that short-term exposure to ambient air pollutants can exacerbate asthma, the role of early life or long-term exposure is less clear. We assessed the association between severe asthma exacerbations with both birth and annual exposure to outdoor air pollutants with a population-based cohort of asthmatic children in the province of Quebec (Canada).

METHOD

Exacerbations of asthma occurring between 1 April 1996 and 31 March 2011 were defined as one hospitalization or emergency room visit with a diagnosis of asthma for children (<13 years old) already diagnosed with asthma. Annual daily average concentrations of ozone (O₃) and nitrogen dioxide (NO₂) were estimated at the child's residential postal code. Satellite based levels of fine particulate (PM2.5) estimated for a grid of 10 km by 10 km were also assigned to postal codes of residence for the whole province. Hazard ratios (HRs) were estimated from Cox models with a gap time approach for both birth and time-dependant exposure.

RESULTS

Of the 162,752 asthmatic children followed (1,020,280 person-years), 35,229 had at least one asthma exacerbation. The HRs stratified by age groups and adjusted for the year of birth, the ordinal number of exacerbations, sex, as well as material and social deprivation, showed an interquartile range increase in the time-dependant exposure to NO₂ (4.95 ppb), O₃ (3.85 ppb), and PM2.5 (1.82 μg/m³) of 1.095 (95% CI 1.058-1.131), 1.052 (95% CI 1.037-1.066) and 1.025 (95% CI 1.017-1.031), respectively. While a positive association was found to PM2.5, no associations were found between exposure at birth to NO₂ or O₃.

CONCLUSIONS

Our results support the conclusion, within the limitation of this study, that asthma exacerbations in asthmatic children are mainly associated with time dependent residential exposures less with exposure at birth.

Childhood Exposure to Ambient Air Pollutants and the Onset of Asthma: An Administrative Cohort Study in Québec

BACKGROUND

Although it is well established that air pollutants can exacerbate asthma, the link with new asthma onset in children is less clear.

OBJECTIVE

We assessed the association between the onset of childhood asthma with both time of birth and time-varying exposures to outdoor air pollutants.

METHOD

An open cohort of children born in the province of Québec, Canada, was created using linked medical-administrative databases. New cases of asthma were defined as one hospital discharge with a diagnosis of asthma or two physician claims for asthma within a 2 year period. Annual ozone (O3) levels were estimated at the child's residence for all births 1999-2010, and nitrogen dioxide (NO2) levels during 1996-2006 were estimated for births on the Montreal Island. Satellite based concentrations of fine particles (PM2.5) were estimated at a 10 km × 10 km resolution and assigned to residential postal codes throughout the province (1996-2011). Hazard ratios (HRs) were assessed with Cox models for the exposure at the birth address and for the time-dependent exposure. We performed an indirect adjustment for secondhand smoke (SHS).

RESULTS

We followed 1,183,865 children (7,752,083 person-years), of whom 162,752 became asthmatic. After controlling for sex and material and social deprivation, HRs for an interquartile range increase in exposure at the birth address to NO2 (5.45 ppb), O3 (3.22 ppb), and PM2.5 (6.50 μg/m3) were 1.04 (95% CI: 1.02, 1.05), 1.11 (95% CI: 1.10, 1.12), and 1.31 (95% CI: 1.28, 1.33), respectively. Effects of O3 and PM2.5 estimated with time-varying Cox models were similar to those estimated using exposure at birth, whereas the effect of NO2 was slightly stronger (HR = 1.07; 95% CI: 1.05, 1.09).

CONCLUSIONS

Asthma onset in children appears to be associated with residential exposure to PM2.5, O3 and NO2.

CITATION

Tétreault LF, Doucet M, Gamache P, Fournier M, Brand A, Kosatsky T, Smargiassi A. 2016. Childhood exposure to ambient air pollutants and the onset of asthma: an administrative cohort study in Québec. Environ Health Perspect 124:1276-1282; http://dx.doi.org/10.1289/ehp.1509838.

Surveillance of social and geographic inequalities in housing-related issues: the case of the Eastern Townships, Quebec (Canada)

Even though health inequalities are conditioned by many aspects of the environment, much of the existing research focuses on the social environment. This emphasis has the effect to neglect other environmental aspects such as its physical dimension. The physical environment, which is linked to housing conditions, may contribute to the uneven distribution of health. In this study, we examined 19 housing-related issues among a representative sample of 2,000 adults residing in a Quebec (Canada) health region characterized by a mix of rural, semi-rural, and urban areas. The distribution of these issues was examined according to socioeconomic and geographic indicators of social position. Summary measures of inequalities were assessed. Our results showed that the prevalence of nearly all housing-related issues was higher among low-income households compared to more affluent ones. Highly educated individuals showed better housing conditions, whereas different issues tended to cluster in deprived or densely populated areas. To conclude, we observed steep gradients between social class and poor housing conditions. This may explain a substantial part of health inequality on the regional scale. The surveillance of housing-related issues is therefore essential to properly inform and mobilize local stakeholders and to develop interventions that target vulnerable groups on this level.

Indoor water and dampness and the health effects on children: a review

Exposure to dampness and mold in indoor environments has received significant attention in recent research. This review focuses on studies looking at the impact of dampness, moisture and microbial agents on children's health. We then look more broadly at how research studies have tried to describe dampness and exposure to moisture. Papers published from 2010 onwards were reviewed and are briefly summarized. Most of the papers using dampness as a proxy for microbial exposure focused on respiratory tract infections, especially asthma. This review highlights new findings and also discusses the variety of approaches used to assess dampness in indoor environments.

Intra-ethnic disparities in respiratory health problems among Hispanic residents impacted by a flood

OBJECTIVES

The primary objective of this article is to assess the respiratory health impacts of a flood disaster on Hispanic people residing in the United States, with a focus on intra-ethnic disparities related to age, sex, socioeconomic status, mold exposure, family conflict, English-language proficiency, and a lack of US citizenship.

METHODS

Data were collected in 2010 after a flood disaster (2006) in El Paso County (Texas), which has a Hispanic majority population. A mail-out population-based survey was used retrospectively to assess respiratory health impacts for 363 people residing in 176 self-identified Hispanic households impacted by the flood; logistic regression was utilized to assess intra-ethnic health disparities in flood impacts.

RESULTS

About 41% of individuals experienced one or more post-flood respiratory health problem. Lower income (OR = 0.532,p = .002), mold exposure (OR = 2.267, p < .001), increased family conflict (OR = 1.452, p = .025), English-language proficiency (OR = 4.023, p < .001) and a lack of US citizenship (OR = 13.111, p = .013) were significantly associated with higher odds of respiratory health problems in the regression model.

CONCLUSION

Statistical findings provide evidence of intra-ethnic disparities in post-flood respiratory health status. Specifically within this Hispanic sample, individuals with lower household incomes, whose homes were covered by larger surface areas of mold, and whose families were characterized by increased tension experienced higher odds of post-flood respiratory health problems. Interestingly, greater English-language proficiency and lacking US citizenship were also risk factors. Given that this is one of the first studies of intra-Hispanic disparities in health following a US-based disaster, the findings underscore the importance of considering diversity within the US Hispanic population when studying environmental and post-disaster respiratory health.

Risk of childhood asthma prevalence attributable to residential proximity to major roads in Montreal, Canada

OBJECTIVES

Exposure to traffic-related air pollutants plays a role in several health outcomes. A large body of evidence tends to link asthma in children with traffic exposure. Increasing asthma prevalence and incidence in children in Canadian cities has been of concern for public health authorities. The following study focuses on estimating the risk of asthma prevalence attributable to residing in proximity to major roads on the Island of Montreal, Canada.

METHODS

Risk functions pertaining to asthma in children and residential proximity to major roads were selected from the literature and applied to Montreal. Asthma prevalence was taken from population-based studies. Population data were retrieved from Canadian census. Exposure was estimated using the proximity to major road and highway category of the Desktop Mapping Technologies Inc. database (DMTI Spatial Inc.).

RESULTS

Based on different studies, the percentage of prevalent asthma cases attributable to residing within 50 metres of a major road or highway for children aged 2, 4 and 6 years varied between 2.4% (0-4.3), 5.6% (0.1-8.6) and 5.9% (0.1-9.0). For the 5-7 year age group residing within 75 m of a major road or highway, the percent of cases was 6.4% (2.6-9.3). For children aged 8 to 10 residing within 75 m of a highway only, the percent of cases was 0.7% (0.2-0.9).

CONCLUSION

These numbers represent the best crude estimates and are an indication of a possible range of cases linked to residential proximity to major roads. As there are uncertainties linked to the application of exposure-response functions, these estimates will be reassessed as new evidence is gathered through further research.

Pediatric asthma: natural history, assessment, and treatment

Wheezing and childhood asthma are not synonymous but rather comprise a heterogeneous group of conditions that have different outcomes over the course of childhood. Most infants who wheeze have a transient condition associated with diminished airway function at birth and have no increased risk of asthma later in life. However, children with persistent wheezing throughout childhood and frequent exacerbations represent the main challenge today. Studying the natural history of asthma is important for the understanding and accurate prediction of the clinical course of different phenotypes. To date, a great improvement has been achieved in reducing the frequency of asthma symptoms. However, neither decreased environmental exposure nor controller treatment, as recommended by the recent National Asthma Education And Prevention Program, can halt the progression of asthma in childhood or the development of persistent wheezing phenotype. This review focuses on the recent studies that led to the current understanding of asthma phenotypes in childhood and the recommended treatments.

Comparability of Internet and telephone data in a survey on the respiratory health of children

BACKGROUND

Mixing survey administration modes has generated concern about the comparability of responses between modes.

OBJECTIVE

To explore the differences in respondent profiles, and responses between Internet and telephone questionnaires in a survey on respiratory diseases.

METHODS

The data were generated from a mixed Internet and telephone survey of respiratory diseases among children in Montreal (Quebec), in 2006. Comparison of 12 selected questions was performed after standardization for respondent education and income. Stratification of analysis on education and income categories was also performed for the questions with significantly divergent responses.

RESULTS

Six questions showed significant differences in responses between modes after standardization. The largest differences among the closed-ended questions were observed for highly prevalent symptoms, dry cough during the night (difference of 9% for positive answer [P<0.01]) and symptoms of allergic rhinitis (difference of 7% for positive answer [P<0.01]). A large discrepancy was also found in the multiple choice question and with an open-ended response (ie, free answer). For the three potentially sensitive questions, a desirability bias was probably present in one question on smoking habits (difference of 2.6 % for positive answer [P<0.05]).

CONCLUSION

The differences observed between Internet and telephone responses to selected questions were not completely explained by socioeconomic disparities among the respondents. In a mixed-mode survey (Internet and telephone), caution should be used when formulating sensitive, complex, open-ended and long-ended questions, and those related to highly prevalent and nonspecific symptoms.

Prevalence of and risk factors for subjective symptoms in urban preschool children without a cause identified by the guardian

OBJECTIVE

The aim of this study was to explore the prevalence of and the risk factors for subjective symptoms without an identified cause by the guardian (SSWICG) in urban preschool children.

METHODS

A questionnaire was used to collect information from 661 urban preschool children. The subjective symptoms were cited from the MM075NA Indoor Environment Quality Investigation Questionnaire. Information about living conditions, kindergarten and outdoor environments was collected, as well as health information from each child.

RESULTS

The prevalence of SSWICG reached 31%, among which the prevalence of general symptoms in the central nervous system (CNS) reached 54.6%. Univariate analysis showed that the materials that made indoor furniture, walls and doors, indoor biological factors, outdoor pollution sources near the house and traffic pollution were associated with SSWICG and mucosal, dermal and general symptoms in the CNS subgroups. Multivariate analysis also showed that furniture materials, traffic pollution, kindergarten environment quality and allergies were associated.

CONCLUSIONS

The prevalence of SSWICG was relatively high. Possible risk factors include indoor furnishing materials, allergy, traffic pollution and kindergarten environmental pollution.

The indoor environment and its effects on childhood asthma

PURPOSE OF REVIEW

Indoor pollutants and allergens cause asthma symptoms and exacerbations and influence the risk of developing asthma. We review recent studies regarding the effects of the indoor environment on childhood asthma.

RECENT FINDINGS

Exposure to some indoor allergens and second hand smoke are causally related to the development of asthma in children. Many recent studies have demonstrated an association between exposure to indoor pollutants and allergens and airways inflammation, asthma symptoms, and increased healthcare utilization among individuals with established asthma. Genetic polymorphisms conferring susceptibility to some indoor exposures have also been identified, and recent findings support the notion that environmental exposures may influence gene expression through epigenetic modification. Recent studies also support the efficacy of multifaceted environmental interventions in childhood asthma.

SUMMARY

Studies have provided significant evidence of the association between many indoor pollutants and allergens and asthma morbidity, and have also demonstrated the efficacy of multifaceted indoor environmental interventions in childhood asthma. There is also a growing body of evidence suggesting that some indoor pollutants and allergens may increase the risk of developing asthma. Future studies should examine mechanisms whereby environmental exposures may influence asthma pathogenesis and expand the current knowledge of susceptibility factors for indoor exposures.