Environmental influences on childhood asthma: Climate change

Association of diurnal temperature range and childhood asthma: a population-based cross-sectional study in a Tropical City, China

BACKGROUND

Climate change has significantly impacted the diurnal temperature range (DTR), particularly in tropical regions of China, where DTR fluctuations are more frequent. While previous studies have primarily focused on the link between short-term DTR exposure and childhood asthma, there is limited information on the long-term effects from large-scale studies.

METHODS

In 2022, a cross-sectional survey involving 9,130 children aged 2-10 years was conducted using stratified cluster random sampling in tropical Sanya, Hainan Province, China. Data on demographics, and asthma symptoms were collected using the validated International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Temperature, precipitation and Normalized Difference Vegetation Index (NDVI) were obtained from remote sensing satellite. A generalized linear model (GLM) was employed to analyze the association between DTR exposure and asthma, and stratified analyses were conducted based on environmental and lifestyle factors.

RESULTS

The prevalence of childhood asthma was 7.57%, with the annual average DTR ranging from 5.15℃ to 7.26℃. After adjusting for potential confounders, each 1℃ increase in DTR was associated with a 65.9% higher risk of asthma (95% CI: 1.058, 2.602). Stratified analyses indicated that the impact of DTR on asthma risk was stronger among children living in areas with higher temperatures, higher precipitation, lower vegetation coverage (measured by NDVI), as well as those who were not breastfed, exposed to passive smoking, or whose mothers had pets during pregnancy.

CONCLUSIONS

In Sanya, increased annual DTR was significantly associated with a higher odds of childhood asthma, and this effect was influenced by environmental and lifestyle factors. Therefore, public health strategies could mitigate childhood asthma risk associated with DTR through urban greening, advocating for breastfeeding, reducing secondhand smoke, and avoiding pet ownership during pregnancy.

EAACI Guidelines on Environmental Science for Allergy and Asthma-Recommendations on the Impact of Indoor Air Pollutants on the Risk of New-Onset Asthma and on Asthma-Related Outcomes

The EAACI Guidelines used the GRADE approach to evaluate the impact of major indoor air pollutants (dampness and mould, cleaning agents, volatile organic compounds and pesticides) on the risk of new-onset asthma and on asthma-related outcomes. The guideline also acknowledges the synergies among indoor air pollutants and other components of the indoor exposome (allergens, viruses, endotoxins). Very low to low certainty of evidence was found for the association between exposure to indoor pollutants and increased risk of new-onset asthma and asthma worsening. Only for mould exposure there was moderate certainty of evidence for new-onset asthma. Due to the quality of evidence, conditional recommendations were formulated on the risk of exposure to all indoor pollutants. Recommendations are provided for prevention, patient care and mitigation in a framework supporting rational decisions for healthcare professionals and patients to individualize and improve asthma management. For policymakers and regulators this evidence-informed guideline supports setting legally binding standards and goals for indoor air quality at international, national and local levels. Asthma management counselled by the current EAACI guidelines can improve asthma-related outcomes but community and governmental measures for improved indoor air quality are needed to achieve significant impact.

Decreased childhood asthma hospitalizations linked to hotter, drier climate with lower wind speed in drylands

Climate change poses a significant threat to human health. Long-term climate effects on childhood asthma hospitalizations depend on the population's geographic region. These effects in tropical drylands are not well understood. The objective of this study is to examine the long-term association between childhood asthma hospitalizations and the climate of a tropical dryland. The study covered 14 municipalities in the Brazilian semiarid. Monthly trends in hospitalizations and climatic variables were calculated. A generalized additive model analyzed the association between these trends, and the Mann-Kendall test determined if trends were increasing, decreasing, or not significant. Thirteen municipalities showed a significant link between hospitalizations and climate variables, especially wind speed, maximum temperature, and humidity. Overall, hospitalizations decreased, correlating with decreasing wind speed and humidity, and increasing temperature. However, no discernable pattern was found between hospitalizations and precipitation. The study emphasizes the need for climate-health analysis to manage childhood asthma amid climate change.

Association of rs7216389 Polymorphism in Gasdermin B (GSDMB) With Childhood Asthma: A Case-Control Study

Objective This study examines the association between the gasdermin B (GSDMB) gene variant rs7216389 and childhood asthma, with a focus on gender-based differences, environmental factors, and lung function measurements in affected children. It highlights the growing prevalence of childhood asthma, its unique features compared to adult-onset asthma, and the substantial healthcare burden it imposes, especially during exacerbations. Methods A case-control study was conducted over 18 months at CMH Lahore, UHS, and Children's Hospital, including 200 participants (100 asthmatics, 100 controls) aged three to 18. Blood samples were analyzed for genetic factors. IBM SPSS Statistics for Windows, Version 25.0 (Released 2017; IBM Corp., Armonk, NY, USA) was used for statistical analysis, with significance at p < 0.05. Ethical approval and informed consent were obtained. Results The study identifies the GSDMB variant rs7216389 as a potential genetic marker for asthma, underscoring its association with the severity of the condition in children. It highlights the challenges of translating genetic findings into clinical practice while emphasizing the therapeutic potential of targeting these genetic markers. The study also sheds light on healthcare costs and the distinctive clinical features of pediatric asthma, further contextualizing its impact. Conclusions This article provides a comprehensive overview of asthma pathogenesis, emphasizing the significance of genetic markers like rs7216389 in the GSDMB gene. It advocates for further research to unravel the complex interplay of genetic, environmental, and immune factors in childhood asthma, intending to develop targeted therapeutic interventions.

Global change, climate change, and asthma in children: Direct and indirect effects - A WAO Pediatric Asthma Committee Report

The twenty-first century has seen a fundamental shift in disease epidemiology with anthropogenic environmental change emerging as the likely dominant factor affecting the distribution and severity of current and future human disease. This is especially true of allergic diseases and asthma with their intimate relationship with the natural environment. Climate change-related variables including increased ambient temperature, heat waves, extreme weather events, air pollution, and rainfall distribution, all can directly affect asthma in children, but each of these variables also indirectly affects asthma via alterations in pollen production and release, outdoor allergen exposure or the microbiome. Air pollution, with its many and varied respiratory consequences, is likely to have the greatest effect, as it has increased globally due to rapid increases in fossil fuel combustion, global population, crowding, and megacities, as well as forest burning and trees succumbing to an increasingly hostile environment. Human activities have also caused substantial deterioration of the global microbiome with reductions in biodiversity for molds, bacteria, and viruses. Reduced microbiome diversity has, in turn, been associated with increases in Th2 allergic responses and allergic disease. The collective effect of these changes has already shifted allergy and asthma disease patterns. Given that changes in climate have been relatively small to date, the unavoidable, much greater shifts in climate in the future are concerning. Determining the relative scale of the direct versus indirect effects of climate change variables is needed if effective avoidance and adaptive measures are to be implemented. This would also require much more basic, epidemiological, and clinical research to understand the causal mechanisms, the most relevant climate factors involved, the regions most affected and, most importantly, effective and actionable adaptation measures. We suggest that allergy and respiratory health workers should follow current guidance to reduce present risks related to climate change and watch for new recommendations to reduce future risks. Since the respiratory system is the one most affected by climate change, they also need to call for more research in this area and show strong leadership in advocating for urgent action to protect children by reducing or reversing factors that have led to our deteriorating climate.

Asthma Inception: Epidemiologic Risk Factors and Natural History Across the Life Course

Asthma is a descriptive label for an obstructive inflammatory disease in the lower airways manifesting with symptoms including breathlessness, cough, difficulty in breathing, and wheezing. From a clinician's point of view, asthma symptoms can commence at any age, although most patients with asthma-regardless of their age of onset-seem to have had some form of airway problems during childhood. Asthma inception and related pathophysiologic processes are therefore very likely to occur early in life, further evidenced by recent lung physiologic and mechanistic research. Herein, we present state-of-the-art updates on the role of genetics and epigenetics, early viral and bacterial infections, immune response, and pathophysiology, as well as lifestyle and environmental exposures, in asthma across the life course. We conclude that early environmental insults in genetically vulnerable individuals inducing abnormal, pre-asthmatic airway responses are key events in asthma inception, and we highlight disease heterogeneity across ages and the potential shortsightedness of treating all patients with asthma using the same treatments. Although there are no interventions that, at present, can modify long-term outcomes, a precision-medicine approach should be implemented to optimize treatment and tailor follow-up for all patients with asthma.

What molecular allergy teaches us about genetics and epidemiology of allergies

PURPOSE OF REVIEW

To delineate pertinent information regarding the application of molecular allergology within the realm of both genetic and epidemiological facets of allergic diseases.

RECENT FINDINGS

The emergence of molecular allergy has facilitated the comprehension of the biochemical characteristics of allergens originating from diverse sources. It has allowed for the exploration of sensitization trajectories and provided novel insights into the influence of genetics and environmental exposure on the initiation and development of allergic diseases. This review delves into the primary discoveries related to the genetics and epidemiology of allergies, facilitated by the application of molecular allergy. It also scrutinizes the impact of environmental exposure across varied geoclimatic, socioeconomic, and lifestyle contexts. Additionally, the review introduces specific models of molecular allergy within the realms of plants and animals.

SUMMARY

The utilization of molecular allergy in clinical practice holds crucially acknowledged diagnostic and therapeutic implications. From a research standpoint, there is a growing need for the widespread adoption of molecular diagnostic tools to achieve a more profound understanding of the epidemiology and natural progression of allergic diseases.

Mediated Mendelian randomization analysis to determine the role of immune cells in regulating the effects of plasma metabolites on childhood asthma

Childhood asthma is a chronic inflammatory disease of the airways, the pathogenesis of which involves multiple factors including genetic predisposition, environmental exposure, and immune system regulation. To date, the causal relationships between immune cells, plasma metabolites, and childhood asthma remain undetermined. Therefore, we aim to utilize the Mendelian randomization approach to assess the causal relationships among immune cells, plasma metabolites, and childhood asthma. This study employed the Mendelian randomization approach to investigate how immune cells influenced the risk of childhood asthma by modulating the levels of plasma metabolites. Five Mendelian randomization methods-inverse variance weighted, weighted median, Mendelian randomization-Egger, simple mode, and weighted mode-were utilized to explore the causal relationships among 731 types of immune cells, 1400 plasma metabolites, and childhood asthma. The instrumental variables for the 731 immune cells and 1400 plasma metabolites were derived from a genome-wide association study meta-analysis. Additionally, sensitivity analyses were conducted to examine the robustness of the results, potential heterogeneity, and pleiotropy. The inverse variance weighted results indicated that HLA DR on dendritic cells (DC) is a risk factor for childhood asthma (OR: 1.08, 95% CI: 1.02-1.14). In contrast, HLA DR on DC acts as a protective factor against elevated catechol glucuronide levels (OR: 0.94, 95% CI: 0.91-0.98), while catechol glucuronide levels themselves serve as a protective factor for childhood asthma (OR: 0.73, 95% CI: 0.60-0.89). Thus, HLA DR on DC can exert a detrimental effect on childhood asthma through the negative regulation of catechol glucuronide levels. The mediating effect was 0.018, accounting for a mediation effect proportion of 23.4%. This study found that HLA DR on DC can exert a risk effect on childhood asthma through the negative regulation of catechol glucuronide levels, providing new strategies for the prevention and treatment of childhood asthma and guiding future research and clinical practice.

Air Quality Monitoring Using Low-Cost Sensors in Urban Areas of Jodhpur, Rajasthan

Air pollution poses a significant health hazard in urban areas across the globe, with India being one of the most affected countries. This paper presents environmental monitoring study conducted in Jodhpur, Rajasthan, India, to assess air quality in diverse urban environments. The study involved continuous indoor and outdoor air quality monitoring, focusing on particulate matter (PM2.5) levels, bioaerosols, and associated meteorological parameters. Laser sensor-based low-cost air quality monitors were utilized to monitor air quality and Anderson 6-stage Cascade Impactor & Petri Dish methods for bioaerosol monitoring. The study revealed that PM2.5 levels were consistently high throughout the year, highlighting the severity of air pollution in the region. Notably, indoor PM2.5 levels were often higher than outdoor levels, challenging the common notion of staying indoors during peak pollution. The study explored the spatial and temporal diversity of air pollution across various land-use patterns within the city, emphasizing the need for tailored interventions in different urban areas. Additionally, bioaerosol assessments unveiled the presence of pathogenic organisms in indoor and outdoor environments, posing health risks to residents. These findings underscore the importance of addressing particulate matter and bioaerosols in air quality management strategies. Despite the study's valuable insights, limitations, such as using low-cost air quality sensors and the need for long-term data collection, are acknowledged. Nevertheless, this research contributes to a better understanding of urban air quality dynamics and the importance of public awareness in mitigating the adverse effects of air pollution. In conclusion, this study underscores the urgent need for effective air quality management strategies in urban areas. The findings provide valuable insights for policymakers and researchers striving to address air pollution in rapidly urbanizing regions.

Climate change and its impact on asthma

ABSTRACT

Earth's climate is changing at an unprecedented pace, primarily due to anthropogenic causes including greenhouse gas emissions. Evidence shows a strong link between climate change and its effects on asthma. Healthcare professionals must be educated to advocate for and lead effective strategies to reduce the health risks of climate change.