Modifiable exposures to air pollutants related to asthma phenotypes in the first year of life in children of the EDEN mother-child cohort study

Exposure to Disinfectants and Cleaning Products and Respiratory Health of Workers and Children in Daycares: The CRESPI Cohort Protocol

Although cleaning tasks are frequently performed in daycare, no study has focused on exposures in daycares in relation to respiratory health. The CRESPI cohort is an epidemiological study among workers (n~320) and children (n~540) attending daycares. The purpose is to examine the impact of daycare exposures to disinfectants and cleaning products (DCP) on the respiratory health of workers and children. A sample of 108 randomly selected daycares in the region of Paris has been visited to collect settled dust to analyze semi-volatile organic compounds and microbiota, as well as sample indoor air to analyze aldehydes and volatile organic compounds. Innovative tools (smartphone applications) are used to scan DCP barcodes in daycare and inform their use; a database then matches the barcodes with the products' compositions. At baseline, workers/parents completed a standardized questionnaire, collecting information on DCP used at home, respiratory health, and potential confounders. Follow-up regarding children's respiratory health (monthly report through a smartphone application and biannual questionnaires) is ongoing until the end of 2023. Associations between DCP exposures and the respiratory health of workers/children will be evaluated. By identifying specific environments or DCP substances associated with the adverse respiratory health of workers and children, this longitudinal study will contribute to the improvement of preventive measures.

Exposure to indoor and outdoor air pollution from solid fuel combustion and respiratory outcomes in children in developed countries: a systematic review and meta-analysis

Epidemiological studies have shown a positive association between exposure to outdoor and indoor solid fuel combustion and adverse health effects. We reviewed the epidemiological evidence from Europe, North America, Australia and New Zealand on the association between outdoor and indoor exposure to solid fuel combustion and respiratory outcomes in children. We performed a systematic review and meta-analysis. Pooled relative risks (RRs) and 95% confidence intervals (CI) were calculated using random-effects models. We identified 74 articles. Due to limited evidence on other exposures and outcomes, we performed meta-analyses on the association between indoor wood burning exposure and respiratory outcomes. The RR for the highest vs the lowest category of indoor wood exposure was 0.90 (95% CI 0.77-1.05) considering asthma as an outcome. The corresponding pooled RRs for lower respiratory infection (LRI) and upper respiratory infection (URI) were 1.11 (95% CI 0.88, 1.41) and 1.11 (95% CI 0.85, 1.44) respectively. No association was found between indoor wood burning exposure and risk of wheeze and cough. Inconsistent and limited results were found considering the relationship between indoor wood burning exposure and other respiratory outcomes (rhinitis and hay fever, influenza) as well as indoor coal burning exposure and respiratory outcomes in children. Results from epidemiological studies that evaluated the relationship between the exposure to outdoor emissions derived from indoor combustion of solid fuels are too limited to allow firm conclusions. We found no association between indoor wood burning exposure and risk of asthma. A slight, but not significant, increased risk of LRI and URI was identified, although the available evidence is limited. Epidemiological studies evaluating the relationship between indoor coal burning exposure and respiratory outcomes, as well as, studies considering exposure to outdoor solid fuels, are too limited to draw any firm conclusions.

Associations of Preconception Exposure to Air Pollution and Greenness with Offspring Asthma and Hay Fever

We investigated if greenness and air pollution exposure in parents’ childhood affect offspring asthma and hay fever, and if effects were mediated through parental asthma, pregnancy greenness/pollution exposure, and offspring exposure. We analysed 1106 parents with 1949 offspring (mean age 35 and 6) from the Respiratory Health in Northern Europe, Spain and Australia (RHINESSA) generation study. Mean particulate matter (PM_2.5 and PM₁₀), nitrogen dioxide (NO₂), black carbon (BC), ozone (O₃) (µg/m³) and greenness (normalized difference vegetation index (NDVI)) were calculated for parents 0–18 years old and offspring 0–10 years old, and were categorised in tertiles. We performed logistic regression and mediation analyses for two-pollutant models (clustered by family and centre, stratified by parental lines, and adjusted for grandparental asthma and education). Maternal medium PM_2.5 and PM₁₀ exposure was associated with higher offspring asthma risk (odds ratio (OR) 2.23, 95%CI 1.32–3.78, OR 2.27, 95%CI 1.36–3.80), and paternal high BC exposure with lower asthma risk (OR 0.31, 95%CI 0.11–0.87). Hay fever risk increased for offspring of fathers with medium O₃ exposure (OR 4.15, 95%CI 1.28–13.50) and mothers with high PM₁₀ exposure (OR 2.66, 95%CI 1.19–5.91). The effect of maternal PM₁₀ exposure on offspring asthma was direct, while for hay fever, it was mediated through exposures in pregnancy and offspring’s own exposures. Paternal O₃ exposure had a direct effect on offspring hay fever. To conclude, parental exposure to air pollution appears to influence the risk of asthma and allergies in future offspring.

Indoor mould exposure, asthma and rhinitis: findings from systematic reviews and recent longitudinal studies

Starting from the Institute of Medicine (IOM) and World Health Organization (WHO) reports, this review provides an overview of the literature published from 2006 to 2017 on the associations between indoor mould exposure and asthma and rhinitis separately in children and adults with a focus on longitudinal epidemiological studies.A systematic search of peer-reviewed literature was performed, including systematic reviews and meta-analyses, longitudinal, incident case-control and panel studies. 61 publications were identified reporting visible mould or mould odour or quantitative assessment of culturable fungi or mould species.In children, visible mould and mould odour were associated with the development and exacerbations of asthma, providing sufficient evidence of a causal relationship. Results from population-based studies in adults were too few and divergent to conclude at more than a limited level of evidence. Exposure to mould in a work building was associated with the incidence and exacerbations of occupational asthma, and we concluded at a sufficient evidence for an association. Systematic reviews, meta-analyses and longitudinal studies on the relationships between mould exposure and allergic rhinitis provide sufficient evidence of an association.This review extended the conclusions of the IOM and WHO reports, and highlighted the need for further longitudinal studies on asthma in adults, and on rhinitis.

Pollution and respiratory disease: can diet or supplements help? A review

Pollution is known to cause and exacerbate a number of chronic respiratory diseases. The World Health Organisation has placed air pollution as the world's largest environmental health risk factor. There has been recent publicity about the role for diet and anti-oxidants in mitigating the effects of pollution, and this review assesses the evidence for alterations in diet, including vitamin supplementation in abrogating the effects of pollution on asthma and other chronic respiratory diseases. We found evidence to suggest that carotenoids, vitamin D and vitamin E help protect against pollution damage which can trigger asthma, COPD and lung cancer initiation. Vitamin C, curcumin, choline and omega-3 fatty acids may also play a role. The Mediterranean diet appears to be of benefit in patients with airways disease and there appears to be a beneficial effect in smokers however there is no direct evidence regarding protecting against air pollution. More studies investigating the effects of nutrition on rapidly rising air pollution are urgently required. However it is very difficult to design such studies due to the confounding factors of diet, obesity, co-morbid illness, medication and environmental exposure.

Wood Stove Pollution in the Developed World: A Case to Raise Awareness Among Pediatricians

Use of wood for residential heating is regaining popularity in developed countries. Currently, over 11 million US homes are heated with a wood stove. Although wood stoves reduce heating costs, wood smoke may adversely impact child health through the emission of gaseous and particulate air pollutants. Our purpose is to raise awareness of this environmental health issue among pediatricians. To summarize the state of the science, we performed a narrative review of articles published in PubMed and Web of Science. We identified 36 studies in developed countries that reported associations of household wood stove use and/or community wood smoke exposure with pediatric health outcomes. Studies primarily investigated respiratory outcomes, with no evaluation of cardiometabolic or neurocognitive health. Studies found community wood smoke exposure to be consistently associated with adverse pediatric respiratory health. Household wood stove use was less consistently associated with respiratory outcomes. However, studies of household wood stoves always relied on participant self-report of wood stove use, while studies of community wood smoke generally assessed air pollution exposure directly and more precisely in larger study populations. In most studies, important potential confounders, such as markers of socioeconomic status, were unaccounted for and may have biased results. We conclude that studies with improved exposure assessment, that measure and account for confounding, and that consider non-respiratory outcomes are needed. While awaiting additional data, pediatricians can refer patients to precautionary measures recommended by the US Environmental Protection Agency (EPA) to mitigate exposure. These include replacing old appliances with EPA-certified stoves, properly maintaining the stove, and using only dry, well-seasoned wood. In addition, several studies have shown mechanical air filters to effectively reduce wood stove pollution exposure in affected homes and communities.

Respiratory Morbidity in Infants Born With a Congenital Lung Malformation

BACKGROUND AND OBJECTIVES

The actual frequency of respiratory symptoms related to congenital pulmonary malformations (CPMs) remains undetermined. The goal of this study was to prospectively evaluate the respiratory symptoms occurring in infants with prenatally diagnosed CPMs, identify factors associated with the occurrence of these symptoms, and evaluate their resolution after surgery.

METHODS

Infectious and noninfectious respiratory symptoms were prospectively collected in a French multicenter cohort of children with CPMs.

RESULTS

Eighty-five children were followed up to the mean age of 2.1 ± 0.4 years. Six children (7%) underwent surgery during the first 28 days of life. Of the 79 remaining children, 33 (42%) had respiratory symptoms during infancy before any surgery. Wheezing was the dominant symptom (24 of 79 [30%]), and only 1 infant had documented infection of the cystic lobe. Symptoms were more frequent in children with noncystic CPMs, prenatally (P = .01) or postnatally (P < .03), and with postnatally hyperlucent CPMs (P < .01). Sixty-six children underwent surgery during the follow-up period, and 40% of them displayed symptoms after the intervention. Six children had documented pneumonia during the postoperative period. At the end of the follow-up, pectus excavatum was observed in 10 children, significantly associated with thoracotomy (P < .02) or with surgery before the age of 6 months (P < .002).

CONCLUSIONS

CPMs are frequently associated with wheezing episodes. Surgery had no significant impact on these symptoms but was associated with a paradoxical increase in pulmonary infections, as well as an increased risk of pectus excavatum after thoracotomy.

Air Pollution During Pregnancy and Cord Blood Immune System Biomarkers

OBJECTIVES

We aimed to determine whether average and trimester-specific exposures to ambient measures of nitrogen dioxide (NO2) and particular matter (PM2.5) were associated with elevated cord blood concentrations of immunoglobulin E (IgE) and two epithelial cell produced cytokines: interleukin-33 (IL-33) and thymic stromal lymphopoietin (TSLP).

METHODS

This study utilized data and biospecimens from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. There were 2001 pregnant women recruited between 2008 and 2011 from 10 Canadian cities. Maternal exposure to NO2 and PM2.5 was estimated using land use regression and satellite-derived models.

RESULTS

We observed statistically significant associations between maternal NO2 exposure and elevated cord blood concentrations of both IL-33 and TSLP among girls but not boys.

CONCLUSIONS

Maternal NO2 exposure may impact the development of the newborn immune system as measured by cord blood concentrations of two cytokines.

Epigenomics and allergic disease

Allergic disease development is affected by both genes and the environment, and epigenetic mechanisms are hypothesized to mediate these environmental effects. In this article, we discuss the link between the environment, DNA methylation and allergic disease, as well as questions of causality inherent to analyses of DNA methylation. From the practical side, we describe characteristics of allergic phenotypes and contrast different epidemiologic study designs used in epigenetic research. We examine methodological considerations, how best to conduct preprocessing and analysis of DNA methylation data sets, and the latest methods, technologies and discoveries in this rapidly advancing field. DNA methylation and other epigenetic marks are firmly entwined with allergic disease, a link that may hold the basis for future allergic disease diagnosis and treatment.

Outdoor air pollution and asthma

Traffic and power generation are the main sources of urban air pollution. The idea that outdoor air pollution can cause exacerbations of pre-existing asthma is supported by an evidence base that has been accumulating for several decades, with several studies suggesting a contribution to new-onset asthma as well. In this Series paper, we discuss the effects of particulate matter (PM), gaseous pollutants (ozone, nitrogen dioxide, and sulphur dioxide), and mixed traffic-related air pollution. We focus on clinical studies, both epidemiological and experimental, published in the previous 5 years. From a mechanistic perspective, air pollutants probably cause oxidative injury to the airways, leading to inflammation, remodelling, and increased risk of sensitisation. Although several pollutants have been linked to new-onset asthma, the strength of the evidence is variable. We also discuss clinical implications, policy issues, and research gaps relevant to air pollution and asthma.

Host and environmental predictors of exhaled breath temperature in the elderly

BACKGROUND

Exhaled breath temperature has been suggested as a new method to detect and monitor pathological processes in the respiratory system. The putative mechanism of this approach is based upon changes in the blood flow. So far potential factors that influence breath temperature have not been studied in the general population.

METHODS

The exhaled breath temperature was measured in 151 healthy non-smoking elderly (aged: 60-80 years) at room temperature with the X-halo device with an accuracy of 0.03°C. We related exhaled breath temperature by use of regression models with potential predictors including: host factors (sex, age) and environmental factors (BMI, physical activity, and traffic indicators).

RESULTS

Exhaled breath temperature was lower in women than in men and was inversely associated with age, physical activity. BMI and daily average ambient temperature were positively associated with exhaled breath temperature. Independent of the aforementioned covariates, exhaled breath temperature was significantly associated with several traffic indicators. Residential proximity to major road was inversely associated with exhaled breath temperature: doubling the distance to the nearest major intense road was observed a decrease of 0.17°C (95% CI: -0.33 to -0.01; p=0.036).

CONCLUSIONS

Exhaled breath temperature has been suggested as a noninvasive method for the evaluation of airway inflammation. We provide evidence that several factors known to be involved in proinflammatory conditions including BMI, physical activity and residential proximity to traffic affect exhaled breath temperature. In addition, we identified potential confounders that should be taken into account in clinical and epidemiological studies on exhaled breath temperature including sex, age, and ambient temperature.

Is the asthma epidemic still ascending?

Asthma is a phenotypically heterogeneous disorder of multifactorial origins that affects 300 million people suffering from asthma and more than 250,000 asthma-related deaths each year. Although treatment for asthma has improved, its prevalence continues to increase, particularly in low and middle income countries, or in some ethnic groups in which prevalence was previously low. Observed spatio-temporal variations in the increased prevalence of asthma depend on exposure to environmental factors. Recently, several arguments are also in favor of the involvement of host susceptibility and stress in the observed increase of asthma prevalence. Further investigations are warranted to better understand mechanisms underlying asthma increase or stagnation.