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

Glimpses of diagnostic tools and treatment of asthma in Sweden, Norway, and Finland from a medico-historical perspective

During the last decades, there has been an accelerating development of diagnostic and treatment possibilities. This paper aims to remind readers of significant milestones in the medical history of asthma. In the early 1800s, important tools for auscultation of the lungs and assessment of vital capacity were developed when Laennec invented the stethoscope and Hutchinson the spirometer. Tests of allergic sensitisation were developed later; the skin prick test in the 1920s, while immunoglobulin E, IgE, was discovered in the 1960s. Dating back to ancient times, asthma has been treated using the sympathomimetic ephedrine and the anticholinergic belladonna. Asthma cigarettes act via anticholinergic effects of Datura stramonium (common name thorn apple), which contains hyoscyamine, scopolamine, and atropine. From the 1930s, ephedrine was replaced by adrenergic agents (e.g., adrenaline) and its further developments. The first selective β2-agonist, salbutamol, was introduced in 1969, followed by long-acting β2-agonists. From the 1920s until 1990, theophylline was frequently used as a bronchodilator, while cromolyn was used as a non-corticosteroid treatment of asthma in the 1970s and 1980s. Introducing inhaled corticosteroids (ICS) in the mid-1970s revolutionised asthma treatment. The use of ICS gathered momentum in the mid-1980s, with improved asthma morbidity and reduced need for hospital treatment. Recent introduction of ICS-formoterol in all treatment steps of asthma further contribute to improved adherence, asthma control and lower risk of exacerbations. At last, in management of severe asthma, monoclonal antibodies targeting IgE or different T2-cytokines, provide significant improvements in symptom control, exacerbation rate, and quality of life for patients.

The relationship between MUC5AC levels in lung and asthma: a meta-analysis based on animal experiments

INTRODUCTION

Asthma is one of the severe respiratory diseases and affects the health of people globally. Animal studies have found that the mucin 5ac (Muc5ac) levels in the lung are associated with asthma. This paper aimed to systematically evaluate the relationship between Muc5ac levels in lung and asthma by extracting relevant data from animal experiments.

METHODS

Literatures published before September 2022 in PubMed, Web of Science, Embase and Cochrane databases were collected. Literatures screening and data extraction were performed according to the criteria and the risks of bias were assessed for the included literatures according to the SYRCLE tool. Type 2 inflammatory asthma model was applied in this paper. Meta-analysis was performed using Stata 16.0 software.

RESULTS

A total of 40 publications containing 347 control mice and 337 mice with asthma were included in this study. Meta-analysis results showed the levels of Muc5ac in BALF of mice in asthma group were significantly higher than that in control group [SMD = 3.50, 95%CI(1.45, 5.54)], and the heterogeneity test results showed I2 = 93.0%, p < 0.05. The mRNA expression levels of Muc5ac in lung tissue of mice in asthma group showed a higher level than that in control group [SMD = 4.46, 95%CI (3.38, 5.55)], and the heterogeneity test results showed I2 = 84.3%, p < 0.01. The protein expression levels of Muc5ac in lung tissue of mice in asthma group were significantly higher than those in control group [SMD = 5.70, 95%CI (4.09,7.31)], and the heterogeneity test results showed I2 = 89.7%, p < 0.01.

CONCLUSION

The meta-analysis clarified the positive relationship between Muc5ac in lung and asthma.

Global, regional, and national burden of asthma and atopic dermatitis, 1990-2021, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021

BACKGROUND

Asthma and atopic dermatitis are common allergic conditions that contribute to substantial health loss, economic burden, and pain across individuals of all ages worldwide. Therefore, as a component of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, we present updated estimates of the prevalence, disability-adjusted life-years (DALYs), incidence, and deaths due to asthma and atopic dermatitis and the burden attributable to modifiable risk factors, with forecasted prevalence up to 2050.

METHODS

Asthma and atopic dermatitis prevalence, incidence, DALYs, and mortality, with corresponding 95% uncertainty intervals (UIs), were estimated for 204 countries and territories from 1990 to 2021. A systematic review identified data from 389 sources for asthma and 316 for atopic dermatitis, which were further pooled using the Bayesian meta-regression tool. We also described the age-standardised DALY rates of asthma attributable to four modifiable risk factors: high BMI, occupational asthmagens, smoking, and nitrogen dioxide pollution. Furthermore, as a secondary analysis, prevalence was forecasted to 2050 using the Socio-demographic Index (SDI), air pollution, and smoking as predictors for asthma and atopic dermatitis. To assess trends in the burden of asthma and atopic dermatitis before (2010-19) and during (2019-21) the COVID-19 pandemic, we compared their average annual percentage changes (AAPCs).

FINDINGS

In 2021, there were an estimated 260 million (95% UI 227-298) individuals with asthma and 129 million (124-134) individuals with atopic dermatitis worldwide. Asthma cases declined from 287 million (250-331) in 1990 to 238 million (209-272) in 2005 but increased to 260 million in 2021. Atopic dermatitis cases consistently rose from 107 million (103-112) in 1990 to 129 million (124-134) in 2021. However, age-standardised prevalence rates decreased-by 40·0% (from 5568·3 per 100 000 to 3340·1 per 100 000) for asthma and 8·3% (from 1885·4 per 100 000 to 1728·5 per 100 000) for atopic dermatitis. In 2021, there were substantial variations in the burden of asthma and atopic dermatitis across different SDI groups, with the highest age-standardised DALY rate found in south Asia for asthma (465·0 [357·2-648·9] per 100 000) and the high-income super-region for atopic dermatitis (3552·5 [3407·2-3706·1] per 100 000). During the COVID-19 pandemic, the decline in asthma prevalence had stagnated (AAPC pre-pandemic -1·39% [-2·07 to -0·71] and during the pandemic 0·47% [-1·86 to 2·79]; p=0·020); however, there was no significant difference in atopic dermatitis prevalence in the same period (pre-pandemic -0·28% [-0·33 to -0·22] and during the pandemic -0·35% [-0·78 to 0·08]; p=0·20). Modifiable risk factors were responsible for 29·9% of the global asthma DALY burden; among them, high BMI was the greatest contributor (39·4 [19·6-60·2] per 100 000), followed by occupational asthmagens (20·8 [16·7-26·5] per 100 000) across all regions. The age-standardised DALY rate of asthma attributable to high BMI was highest in high-SDI settings, whereas the contribution of occupational asthmagens was highest in low-SDI settings. According to our forecasting models, we expect 275 million (224-330) asthma cases and 148 million (140-158) atopic dermatitis cases in 2050, with population growth driving this increase. However, age-standardised prevalence rates are expected to remain stable (-23·2% [-44·4 to 5·3] for asthma and -1·4% [-9·1 to 7·0] for atopic dermatitis) from 2021 to 2050.

INTERPRETATION

Although the increases in the total number of asthma and atopic dermatitis cases will probably continue until 2050, age-standardised prevalence rates are expected to remain stable. A considerable portion of the global burden could be managed through efforts to address modifiable risk factors. Additionally, the contribution of risk factors to the burden substantially varied by SDI, which suggests the need for tailored initiatives for specific SDI settings. The growing number of individuals expected to be affected by asthma and atopic dermatitis in the future suggests that it is essential to improve our understanding of risk factors for asthma and atopic dermatitis and collect disease prevalence data that are globally generalisable.

FUNDING

Gates Foundation.

Managing childhood asthma with an eye toward environmental, social, and behavioral features

Discussions on asthma management tend to focus on the therapeutic aspects when updates on asthma strategies are released. However, many other components of asthma management are now receiving increased attention, as we seek to make right on health disparities and strive toward health equity. In addition, with the therapeutic aspects of asthma, we now realize that our anti-inflammatory approaches largely address the high T2 component of airway inflammation. However, we know very little about what we can do to control the other inflammatory features that contribute to asthma. Factors, such as environmental exposures, social determinants of health, and risk-taking behaviors may be at the root of asthma persistence, progression, and comorbidities. We will continue to learn methods to identify these issues and draw them into a shared decision-making approach for dialogue with patients and their caregivers. This review provides information and tools to address the nonpharmacologic aspects of asthma management.

Utilization of Dietary Supplements in People with the Atopic Triad in Korea: A Cross-Sectional Study Using KNHANES (2018-2021)

Background and Objectives: Studies investigating the types of dietary supplements associated with the atopic triad using large-scale data remain limited. We assessed the prevalence of the atopic triad, the types of dietary supplements used, and their associations in Korean adults using a 4-year national survey data. Materials and Methods: This cross-sectional study utilized data from the Korea National Health and Nutrition Examination Survey (2018-2021). Adults aged ≥ 19 years were included. Descriptive statistics were used to summarize participants' overall characteristics and estimate the national prevalence of the atopic triad, defined as a diagnosis of asthma, allergic rhinitis, or atopic dermatitis. Logistic regression analyses were conducted using each atopic condition as a dependent variable, with the types of dietary supplements currently used as independent variables. Covariates included socioeconomic status, lifestyle factors, frailty, and diet. Dietary supplements were categorized as multivitamins/minerals, vitamin C, vitamin D, vitamin A/lutein, propolis, omega-3, probiotics, red ginseng, calcium, or iron. Results: A total of 18,182 adults were analyzed, representing an estimated 52.8 million adults (mean age: 47 years; 50% male). Of these, 21% reported a history of any atopic triad, and 61% were current supplement users. Logistic regression showed significantly higher odds of all three atopic conditions among users of propolis (asthma: OR 1.90, 95% CI 1.04-3.47; allergic rhinitis: OR 1.64, 95% CI 1.25-2.17; atopic dermatitis: OR 2.04, 95% CI: 1.18-3.52), and higher odds of allergic rhinitis among users of probiotics (OR 1.21, 95% CI 1.06-1.38) and vitamin D (OR 1.43, 95% CI 1.16-1.75). Conclusions: A positive association was found between propolis use and all three atopic conditions. Also, a positive association was found between probiotics or vitamin D use and allergic rhinitis. We did not find significant associations with the other supplements. Further research in establishing causal relationships between the dietary supplements and atopic conditions are needed.

Gut-lung Axis mediates asthma pathogenesis: Roles of dietary patterns and their impact on the gut microbiota

The gut-lung axis, a vital signaling network linking the gastrointestinal and pulmonary systems, regulates immune responses and the progression of respiratory diseases. Nutritional components can modulate the gut microbiome and regulate the synthesis of critical intestinal microbial metabolites, which are essential for maintaining immune homeostasis and supporting respiratory health. Conversely, poor dietary habits exacerbate asthma and other respiratory conditions through the modulation of systemic inflammation and immune responses. Dietary interventions, such as the Mediterranean diet, are reported to restore microbial balance and improve respiratory health by increasing the production of anti-inflammatory metabolites, potentiating immune responses, and preserving epithelial barrier integrity. In contrast, Western dietary patterns, which are characterized by high fat and low fiber intake, disrupt microbial diversity, resulting in increased levels of pro-inflammatory metabolites that aggravate airway inflammation and asthma severity. This review aimed to elucidate the mechanisms underlying the regulatory effects of gut microbes and their metabolites on asthma. Additionally, previous findings related to the gut-lung axis have been summarized, providing insights into potential therapeutic strategies for asthma management.

Multifunctional Boron-based 2D Nanoplatforms Ameliorate Severe Respiratory Inflammation by Targeting Multiple Inflammatory Mediators

Effective management of serious respiratory diseases, such as asthma and recalcitrant rhinitis, remains a global challenge. Here, it is shown that induced sputum supernatants (ISS) from patients with asthma contain higher levels of cell-free DNA (cfDNA) compared to that of healthy volunteers. Although cfDNA scavenging strategies have been developed for inflammation modulation in previous studies, this fall short in clinical settings due to the excessive neutrophil extracellular trap (NET) formation, reactive oxygen and nitrogen species (RONS) and bacterial infections in injured airway tissues. Based on this, a multifunctional boron-based 2D nanoplatform B-PM is designed by coating boron nanosheets (B-NS) with polyamidoamine generation 1 (PG1) dendrimer, which can simultaneously target cfDNA, NETs, RONS, and bacteria. The effects of B-PM in promoting mucosal repair, reducing airway inflammation, and mucus production have been demonstrated in model mice, and the therapeutic effect is superior to dexamethasone. Furthermore, flow cytometry with clustering analysis and transcriptome analysis with RNA-sequencing are adopted to comprehensively evaluate the in vivo anti-inflammation therapeutic effects. These findings emphasize the significance of a multi-targeting strategy to modulate dysregulated inflammation and highlight multifunctional boron-based 2D nanoplatforms for the amelioration of respiratory inflammatory diseases.

Monocyte CCL2 signaling possibly contributes to increased asthma susceptibility in type 2 diabetes

In recent years, the respiratory system has been increasingly recognized as a key target organ in diabetes. Although observational studies have established significant clinical associations between type 2 diabetes (T2D), antidiabetic medication use, and asthma, the causal relationships and underlying molecular mechanisms remain unclear. This study employed a bidirectional two-sample Mendelian randomization (MR) approach combined with bioinformatics analysis to explore the causal relationships between T2D and asthma subtypes and complications, with a focus on immune-regulatory mechanisms. The MR analysis utilized inverse-variance weighted (IVW) and meta-analysis methods to evaluate overall effects, with sensitivity analyses confirming the robustness of the findings. Bioinformatics analysis focused on differential gene expression and pathway enrichment to identify potential molecular networks. The MR analysis showed that T2D has a significant positive causal effect on asthma (P < 0.05), with severe autoimmune T2D showing strong associations with specific asthma subtypes (eosinophilic and mixed asthma) and complications (e.g., acute respiratory infections and pneumonia) (P < 0.05). Bioinformatics analysis identified the monocyte-CCL2 signaling axis as a key mechanism linking T2D and asthma, where hyperglycemia-induced monocyte activation may promote asthma development. These findings reveal shared inflammatory pathways and deepen our understanding of the molecular mechanisms linking these two chronic diseases.

Causal relationships between allergic diseases and significant declines in lung function: a multivariable Mendelian randomization study

BACKGROUND

Asthma and other allergic diseases are increasing globally each year, with some patients experiencing the co-occurrence of two or more conditions, significantly impacting their quality of life. While these diseases may share certain immune mechanisms, the independent causal relationships between them and lung function remain unclear.

OBJECTIVE

This study aims to investigate the independent and interactive effects of allergic asthma, atopic dermatitis, allergic rhinitis, and allergic conjunctivitis on significant declines in lung function. By elucidating the potential causal relationships between these allergic diseases and reduced lung function, we hope to provide valuable scientific evidence for managing asthma patients who are co-morbid with multiple allergic conditions.

METHODS

In this study, we conducted Mendelian randomization (MR) analysis using data from the FinnGen database and the UK Biobank. We rigorously selected instrumental variables (IVs) based on established criteria and employed both univariable and multivariable MR approaches to investigate the relationship between various allergic diseases and significant declines in lung function.

RESULTS

In univariable MR analysis, the inverse variance-weighted (IVW) method or the weighted median approach indicated a causal relationship between allergic conjunctivitis, atopic dermatitis, and allergic asthma with significant declines in lung function. However, in multivariable MR analysis, the independent effects of atopic dermatitis and allergic conjunctivitis on lung function were no longer significant. Only allergic asthma continued to show a significant causal relationship with decreased lung function (OR [95%CI]: 1.019 [1.008-1.030], p < .001).

CONCLUSIONS

This study suggests that while atopic dermatitis and allergic conjunctivitis may indirectly affect lung function and lead to significant declines, their independent effects are not notable when asthma is well-controlled. Therefore, clinicians should recognize that acute exacerbations of allergic diseases are unlikely to be the primary reason for significant declines in lung function among asthma patients with multiple allergic conditions, provided that their asthma is well-managed.

Impact of Saharan Dust and SERPINA1 Gene Variants on Bacterial/Fungal Balance in Asthma Patients

The Canary Islands, a region with high asthma prevalence, are frequently exposed to Saharan Dust Intrusions (SDIs), as are a wide range of countries in Europe. Alpha-1 antitrypsin (SERPINA1 gene) regulates the airway's inflammatory response. This study analyzed the combined effect of SDI exposure and SERPINA1 variants on bacterial/fungal DNA concentrations in saliva and pharyngeal samples from asthmatic patients. Bacterial and fungal DNAs were quantified by qPCR in 211 asthmatic patients (GEMAS study), grouped based on their exposure to daily PM10 concentrations. Associations between SDI exposure, microbial DNA concentrations, and nine variants in SERPINA1 were tested using linear regression models adjusted for confounders. The ratio between bacterial and fungal DNA was similar in saliva and pharyngeal samples. SDI exposure for 1-3 days was enough to observe significant microbial DNA change. Increased bacterial DNA concentration was detected when SDI exposure occurred 4-10 days prior to sampling, while exposure between days 1 and 3 led to a reduction in the fungal DNA concentration. The T-allele of SERPINA1 SNV rs2854254 prevented the increase in the bacterial/fungal DNA ratio in pharyngeal samples after SDI exposure. The bacterial/fungal DNA ratio represents a potential tool to monitor changes in the microbiome of asthmatic patients.

Exposure to climate change-related extreme events in the first year of life and occurrence of infant wheezing

INTRODUCTION

Climate change increases the intensity and frequency of extreme events, which will most impact younger generations. Within the NINFEA birth cohort, we investigated the relationship between exposure to such events during the first year of life and infant respiratory health.

METHODS

The NINFEA cohort study recruited pregnant women across 11 years in Italy, allowing for climatic variability exploitation by birth place and time. We combined geocoded addresses with climate data, to derive children's cumulative exposure to the following extreme events during their first year: (i) heatwaves (i.e. 3 + consecutive days, with maximum temperature > 35 °C); (ii) days with wildfire PM2.5 >15 μg/m3 and (iii) daily precipitation > 100 mm; (iv) months with exceptional drought. Logistic regression models estimated the relationship between each exposure and wheezing at 6-18 months, adjusting for individual and contextual factors.

RESULTS

Wheezing prevalence in the cohort was 17.6%. The exposure to each additional heatwave in the first year of life increased wheezing risk by 16%, with an odds ratio (OR) of 1.16 and a 95% Confidence Interval (CI) of 1.00;1.35. The OR for each month of extreme drought exposure was 1.10, 95%CI 0.95; 1.26. Results for wildfire PM2.5 were unclear with wider confidence intervals (OR for each high exposure day:1.36, 95% CI 0.85; 2.16). Wheezing was not associated with extreme precipitation.

CONCLUSIONS

Exposure to multiple extreme events, especially heatwaves, in the first year of life is associated with later infant respiratory health suggesting the need to implement climate change mitigation policies to protect long-term health.