Natural progression of childhood asthma symptoms and strong influence of sex and puberty

Reporting of asthma mobile health data for clinical practice: a qualitative study of pediatric provider perspectives

OBJECTIVE

Mobile health (mHealth), defined as the use of mobile phones or applications in healthcare, has been developed to enhance asthma care; yet implementation is inconsistent, and few studies have focused on provider perspectives on use in daily practice. The purpose of this study was to explore primary care pediatric provider perspectives regarding mHealth use in clinical practice for children with asthma.

METHODS

A qualitative, descriptive approach was utilized to perform semi-structured interviews on asthma mHealth use with providers caring for children with asthma. Interview transcripts were coded by two independent investigators and any differences were reconciled. Interviews continued until thematic saturation was achieved.

RESULTS AND CONCLUSIONS

Seventeen pediatric providers were recruited and interviewed. Three themes identified included implementation benefits, implementation barriers, and reporting desires, with 11 subthemes. Many subthemes were consistent across providers (e.g. self-management benefits and electronic medical record integration), while others such as provider clinical burden and approach to integrating mHealth data reports into daily workflow demonstrated variability. Provider perspectives highlight the potential of mHealth applications in asthma self-management while offering challenges related to clinical burden and suggestions for reporting and workflow integration. These results provide valuable perspectives on mHealth use and reporting to ensure provider efficiency and technology-enhanced asthma care. This study investigates pediatric provider perspectives on asthma mobile health use and reporting in daily practice, a topic that has not sufficiently been explored within the literature. Results can guide best practices, encourage more consistent use, and maximize the benefits of asthma mHealth tools by providers.

Association between dietary choline intake and asthma and pulmonary inflammation and lung function: NHANES analysis 2009-2018

BACKGROUND

Asthma is a chronic inflammatory condition, and choline may alleviate airway inflammation and oxidative stress but studies on the association between dietary choline and asthma remain limited. The purpose of this study is to investigate the associations between dietary choline intake and asthma, as well as pulmonary inflammation and lung function in children and adults.

METHODS

In our research, we employed the data of the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2018, including 7,104 children and 16,580 adults. We used fractional exhaled nitric oxide (FENO) to assess pulmonary inflammation and forced expiratory volume in one second (FEV1), forced vital capacity (FVC), the FEV1/FVC ratio, peak expiratory flow rate (PEF), predicted FEV1% and predicted FVC% to assess lung function. Binary logistic regression, linear regression, and the restricted cubic splines were used to analyze the associations between dietary choline intake and asthma and pulmonary inflammation and lung function.

RESULTS

In children, we observed the positive associations between the natural logarithmic transformation of choline (ln-choline) and ln-FEV1 [ β:0.011; 95%CI: (0.004,0.018)] and ln-FVC [ β:0.009; 95%CI: (0.002,0.016)]. In adult males, the ln-choline was positively associated with ln-FEV1[ β:0.018; 95%CI: (0.011,0.024)], ln-FVC [ β:0.020; 95%CI: (0.014,0.026)], ln-PEF [ β:0.014; 95%CI: (0.007,0.022)], ln-predicted FEV1% [ β: 0.007; 95%CI: (0.001, 0.013)] and ln-predicted FVC%[ β: 0.010; 95%CI: (0.005, 0.015)] and negatively associated with FENO [ β: -0.029; 95%CI: (-0.049, -0.009)]. In unadjusted and partially adjusted models, adult females with ln-choline in the highest quartile had 25.2% (95%CI:9.4-38.3%) and 23.8% (95%CI:7.6-37.1%) decreased odds of asthma compared to those with the lowest quartile group. In the dose-response relationships of dietary choline and pulmonary inflammation and lung function indicators in adults, there existed threshold and saturation effects.

CONCLUSION

The associations between dietary choline and lung function indicators such as FEV1 and FVC are positive in children and adults. The association between dietary choline and pulmonary inflammation is negative only in adults.

Current Challenges in Pediatric Asthma

Asthma is a chronic lung disease characterized by reversible bronchoconstriction and inflammation of the bronchi. Its increasing prevalence in childhood as well as different triggers make asthma a challenging disease in several ways: defining its phenotype/endotype, the diagnostic approach (especially in younger children), therapeutic options, and systematic follow-up. Considering these problems, this review approaches the current status and limitations of guidelines used for asthma management in children. It also emphasizes the key points which could lead to a better understanding and the direction to take in future studies.

Sex differences in tissue immunity

Androgen signaling skews skin immunity toward reduced inflammation in male mice.

Winds of change a tale of: asthma and microbiome

The role of the microbiome in asthma is highlighted, considering its influence on immune responses and its connection to alterations in asthmatic patients. In this context, we review the variables influencing asthma phenotypes from a microbiome perspective and provide insights into the microbiome's role in asthma pathogenesis. Previous cohort studies in patients with asthma have shown that the presence of genera such as Bifidobacterium, Lactobacillus, Faecalibacterium, and Bacteroides in the gut microbiome has been associated with protection against the disease. While, the presence of other genera such as Haemophilus, Streptococcus, Staphylococcus, and Moraxella in the respiratory microbiome has been implicated in asthma pathogenesis, indicating a potential link between microbial dysbiosis and the development of asthma. Furthermore, respiratory infections have been demonstrated to impact the composition of the upper respiratory tract microbiota, increasing susceptibility to bacterial diseases and potentially triggering asthma exacerbations. By understanding the interplay between the microbiome and asthma, valuable insights into disease mechanisms can be gained, potentially leading to the development of novel therapeutic approaches.

Obstructive sleep apnea in asthmatic children: a cross-sectional study about prevalence and risk factors

OBJECTIVES

Primary objectives were to analyze the prevalence of obstructive sleep apnea in (1) boys and girls, and (2) severe asthma versus moderate and mild cases. The authors hypothesized that girls and severe asthma would have a higher prevalence of obstructive sleep apnea.

METHODS

Cross-sectional evaluation of asthmatic children attending a tertiary Pediatric Pulmonology clinic. The authors performed a history, physical examination, pulmonary function test, and home sleep apnea test.

RESULTS

The authors studied 80 consecutive patients, 7-18 years old, mean age of 11.6 years (standard deviation 2.7), 51.3% female, and 18.5% obese. Pulmonary function tests were obtained from 80 volunteers, 45% with obstruction pattern. Home sleep apnea tests were available from 76 volunteers, with a mean obstructive respiratory index of 1.8 events/h. Obstructive sleep apnea was found in 49 volunteers (61.2%). The authors did not find associations between obstructive sleep apnea and sex or asthma severity.

CONCLUSIONS

Obstructive sleep apnea was frequent among these asthmatic children. Sex and asthma severity were not risk factors. Considering the interrelationship of both diseases, it is worth keeping in mind the possibility of obstructive sleep apnea among children and teenagers with asthma.

Androgen receptor signaling protects male mice from the development of immune response to peanut

OBJECTIVES

Peanut (PN) allergy is a major public health concern. Recent research has brought clarity about how individuals become sensitized to PN allergen with routes known through the skin, as well as the airway. Still unclear, however, is the role of sex hormones on the development of allergic immune responses to PN. This study examines the role of androgen receptor (AR) signaling in regulating PN-specific immune responses.

METHODS

We utilized a 4-week inhalation mouse model of PN allergy that is known to drive the production of PN-specific antibodies and elicit systemic anaphylaxis following PN challenge. Wildtype (WT) male, female, and androgen receptor-deficient testicular feminization mutant (ARTfm) male mice were examined using this model to document sex differences in PN allergy. To determine if sex differences also existed in the cellular immune response, this study utilized a 3-day inhalation mouse model of PN to examine the response of group 2 innate lymphoid cells (ILC2s). WT male and female mice were examined using this model to document sex differences in ILC2 response within the lungs.

RESULTS

AR use is critical in regulating PN-specific antibody levels. We found that ARTfm males have a higher antibody response and significantly worse anaphylactic response following PN challenge relative to WT males. WT males also exhibit a less severe anaphylactic response compared to ARTfm male and female mice. Lastly, we discovered that lung ILC2s from female mice respond more robustly to PN compared to ILC2s within WT male mice.

CONCLUSIONS

Taken together, this study suggests that male sex hormones, namely androgens, negatively regulate allergic immune responses to PN.

Zinc finger protein 33B demonstrates sex interaction with atopy-related markers in childhood asthma

BACKGROUND

Sex differences related to immune responses can influence atopic manifestations in childhood asthma. While genome-wide association studies have investigated a sex-specific genetic architecture of the immune response, gene-by-sex interactions have not been extensively analysed for atopy-related markers including allergy skin tests, IgE and eosinophils in asthmatic children.

METHODS

We performed a genome-wide gene-by-sex interaction analysis for atopy-related markers using whole-genome sequencing data based on 889 trios from the Genetic Epidemiology of Asthma in Costa Rica Study (GACRS) and 284 trios from the Childhood Asthma Management Program (CAMP). We also tested the findings in UK Biobank participants with self-reported childhood asthma. Furthermore, downstream analyses in GACRS integrated gene expression to disentangle observed associations.

RESULTS

Single nucleotide polymorphism (SNP) rs1255383 at 10q11.21 demonstrated a genome-wide significant gene-by-sex interaction (pinteraction=9.08×10-10) for atopy (positive skin test) with opposite direction of effects between females and males. In the UK Biobank participants with a history of childhood asthma, the signal was consistently observed with the same sex-specific effect directions for high eosinophil count (pinteraction=0.0058). Gene expression of ZNF33B (zinc finger protein 33B), located at 10q11.21, was moderately associated with atopy in girls, but not in boys.

CONCLUSIONS

We report SNPs in/near a zinc finger gene as novel sex-differential loci for atopy-related markers with opposite effect directions in females and males. A potential role for ZNF33B should be studied further as an important driver of sex-divergent features of atopy in childhood asthma.

Control of Immunity and Allergy by Steroid Hormones

Steroid hormones, especially glucocorticoids, androgens, and estrogens, have profound influence on immunity. Recent studies using cell-type specific steroid hormone receptor-deficient mice have revealed the precise roles of some of these hormones in the immune system. Glucocorticoids are known to have strong anti-inflammatory and immunosuppressive effects and pleiotropic effects on innate and adaptive immune responses. They suppress the production of inflammatory cytokines by macrophages and DCs and the production of IFN-γ by NK cells, thus inhibiting innate immunity. By contrast, glucocorticoids enhance the immune response by inducing the expression of IL-7R and CXCR4 in T cells and the accumulation of T cells in lymphoid organs in accordance with the diurnal change of the glucocorticoid concentration. Thus, glucocorticoids suppress innate immunity but enhance adaptive immunity. Androgens suppress the homeostasis and activation of ILC2s and the differentiation of Th2 and Th17 cells and enhance the suppressive function of Tregs, thereby alleviating allergic airway inflammation. Thus, these steroid hormones have pleiotropic functions in the immune system. Further investigations are awaited on the regulation of immunity and allergy by estrogens using cell-specific steroid hormone receptor-deficient mice.

Understanding sex differences in the allergic immune response to food

Food allergies are of great public health concern due to their rising prevalence. Our understanding of how the immune system reacts to food remains incomplete. Allergic responses vary between individuals with food allergies. This variability could be caused by genetic, environmental, hormonal, or metabolic factors that impact immune responses mounted against allergens found in foods. Peanut (PN) allergy is one of the most severe and persistent of food allergies, warranting examination into how sensitization occurs to drive IgE-mediated allergic reactions. In recent years, much has been learned about the mechanisms behind the initiation of IgE-mediated food allergies, but additional questions remain. One unresolved issue is whether sex hormones impact the development of food allergies. Sex differences are known to exist in other allergic diseases, so this poses the question about whether the same phenomenon is occurring in food allergies. Studies show that females exhibit a higher prevalence of atopic conditions, such as allergic asthma and eczema, relative to males. Discovering such sex differences in allergic diseases provide a basis for investigating the mechanisms of how hormones influence the development of IgE-mediated reactions to foods. Analysis of existing food allergy demographics found that they occur more frequently in male children and adult females, which is comparable to allergic asthma. This paper reviews existing allergic mechanisms, sensitization routes, as well as how sex hormones may play a role in how the immune system reacts to common food allergens such as PN.

Allergic Rhinitis and House Dust Mite Sensitization Determine Persistence of Asthma in Children

OBJECTIVE

To specify clinical and immunological parameters of the mechanisms, which may lead to development of persistent asthma, or regression of the disease symptoms.

METHODS

Eighty children with childhood asthma, diagnosed in the past by using the modified Asthma Predicted Index (mAPI), were divided into two groups: remission group and persistent group. There were 3 study visits (baseline, at 6 mo, and at 12 mo). Clinical remission of asthma was defined as the absence of asthma symptoms for at least 12 mo without treatment. The patients could switch from one group to another during the 12 mo of follow-up. Clinical, inflammatory, and immunoregulatory predictors of asthma remission/persistence were analyzed.

RESULTS

The presence of mAPI criteria as well as house dust mite (HDM) allergy and allergic rhinitis at 7-10 y, were associated with a reduced prevalence of asthma remission. The increased eosinophil blood count in mAPI criteria was associated with a lower expression of CD25 positive cells. HDM allergy was associated with a higher fractional exhaled nitric oxide (FeNO) level (p = 0.0061) and higher expression of CD25CD71 (p = 0.0232). Allergic rhinitis was associated with a higher expression of PPAR (p = 0.0493) and CD25CD71 (p = 0.0198), and lower expression of glycoprotein A repetitions predominant (GARP).

CONCLUSIONS

Persistence of childhood asthma was largely determined by the presence of allergic rhinitis and sensitization to HDM. Additionally, API criteria but not immunoregulation processes, were related to asthma persistence.

Longitudinal measures of phthalate exposure and asthma exacerbation in a rural agricultural cohort of Latino children in Yakima Valley, Washington

Phthalates are a class of widely used synthetic chemicals found in commonly used materials and products. Epidemiological studies suggest phthalate exposure is associated with asthma outcomes, though most studies have not investigated phthalates as triggers of exacerbations in children diagnosed with asthma. This study used data from the Home Air in Agriculture Pediatric Intervention Trial (HAPI) to examine relationships between phthalate exposure and outcomes related to childhood asthma exacerbation. We used measures of phthalate metabolites and respiratory health measures including fractional exhaled nitric oxide (FENO), the Asthma Control Test (ACT), caregiver report of symptoms, and urinary leukotriene E₄ (uLTE₄) to estimate longitudinal associations using mixed effects models, adjusted for covariates. For 100% (i.e., doubling) increases in mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-2-ethylhexyl phthalate (MEHP), and mono-ethyl phthalate (MEP), concentrations of FENO increased by 8.7% (95% CI: 0.7-17.3), 7.2% (95% CI: 0.0-14.9), and 6.4% (95% CI: 0.0-13.3), respectively. All phthalate metabolites demonstrated associations with uLTE₄, effect sizes ranging from an 8.7% increase in uLTE₄ (95% CI: 4.3-12.5) for a 100% increase in MEHP to an 18.1% increase in uLTE₄ (95% CI: 13.3-23.1) for a 100% increase in MNBP. In models of caregiver report of symptoms, no phthalate metabolites were significantly associated in primary models. No phthalate metabolites were associated with standardized ACT score. Our results suggest urinary phthalate metabolites are significant predictors of inflammatory biomarkers related to asthma exacerbation in children but not child and caregiver report of airway symptomatology.

Association Between Asthma Control Trajectories in Preschoolers and Long-Term Asthma Control

BACKGROUND

The potential influence of asthma control in early life on long-term outcomes in childhood remains largely unknown.

OBJECTIVE

To examine whether asthma control trajectories in the 2 years after diagnosis in preschoolers are associated with long-term unsatisfactory asthma control.

METHODS

We conducted a multicenter population-based retrospective cohort study, including four Canadian provincial birth cohorts derived from administrative databases. We included preschoolers (aged <5 years) with a diagnosis of asthma, defined as having one hospitalization or two physician visits for asthma within 2 years. Asthma control trajectories, ascertained over four 6-month periods after diagnosis using a validated index, were classified as controlled throughout, improving control, fluctuating control, worsening control, and out of control throughout. Long-term unsatisfactory control was defined as four or more short-acting β₂-agonist average doses per week or an exacerbation, measured within 6 months before index ages 6, 8, 10, 12, 14, and 16 years. Average risk ratios for long-term unsatisfactory control across all index ages were estimated using a robust Poisson model by province and meta-analyzed with a random effects model.

RESULTS

In 50,188 preschoolers with asthma, the pooled average risk of having unsatisfactory control at any index age was 42% (95% confidence interval, 34.6-49.4). Compared with children who were controlled throughout, incrementally higher average risk ratios (95% confidence interval) of long-term unsatisfactory control were observed in each trajectory: improving control, 1.38 (1.28-1.49); fluctuating control, 1.54 (1.40-1.68); worsening control, 1.70 (1.55-1.86) and out of control throughout, 2.00 (1.80-2.21).

CONCLUSIONS

Suboptimal asthma control trajectories shortly after a preschool diagnosis were associated with long-term unsatisfactory asthma control. Early control trajectories appear to be promising for predicting the risk for long-term adverse outcomes.

[Asthma and suicidal behavior in adolescents: a literature review]

INTRODUCTION

Adolescence is a difficult time in life and asthma has major psychological consequences for adolescents.

OBJECTIVES

This systematic literature review focused on the association between asthma and suicidal behaviors (suicidal ideations [SI], suicide plans [SP] and suicide attempts [SA]) among adolescents in the general population.

METHOD

Research on Medline for the 1980-2021 period. Objectives This systematic literature review focused on the association between asthma and suicidal behaviors (suicidal ideations [SI], suicide plans [SP] and suicide attempts [SA]) among adolescents in the general population.

RESULTS

An overwhelming majority of the studies taken into consideration demonstrated a significant positive association between asthma and suicidal behaviors. Among the 10 studies assessing SI (with or without SP), 9 of them found a significant positive association between asthma and SI. Eight studies assessed SA; five cross-sectional studies and one prospective study demonstrated a significant positive association between asthma and SA. Only one case-control study did not find a significant positive association between asthma and SA after hospitalization for asthma. The two cross-sectional studies assessing suicidal risk taken as a whole (SI, SP and SA) demonstrated a significant positive association between asthma and at least one suicidal behavior. (OR=1.71; P<0.001). However, several studies did not include depression as an adjustment factor.

CONCLUSION

It is important that healthcare professionals assess suicide risk in adolescent suffering from asthma, the objective being to avoid SA or death from SA.

Predicting the course of asthma from childhood until early adulthood

PURPOSE OF REVIEW

To communicate recent insights about the natural history of childhood asthma, with a focus on prediction of persistence and remission of childhood asthma, up to early adulthood.

RECENT FINDINGS

Lung function around the age of 8-9 years is the strongest predictor: obstructive lung function predicts asthma persistence up to early adulthood, whereas normal lung function predicts remission. The ability to predict asthma remission improves when lung function is combined with blood eosinophil levels and degree of bronchial hyperresponsiveness. Interventions, such as inhaled corticosteroids and immunotherapy do not appear to alter the course of asthma. Epigenetic studies have revealed potential novel biomarkers of asthma remission, such as micro-RNA patterns in blood. Specifically, lower serum levels of mi-R221-5p, which is associated with lower IL-6 release and eosinophilic inflammation, predict remission. Higher levels of blood DNA-methylation of a CpG site in Peroxisomal Biogenesis Factor 11 Beta were associated with asthma remission.

SUMMARY

Lung function, allergic comorbidity and polysensitization in childhood predict the course of asthma. Recent epigenetic studies have provided a better understanding of underlying pathological processes in asthma remission, which may be used to improve prediction or develop novel treatments aimed at altering the course of asthma.

Sex Disparities in Asthma Development and Clinical Outcomes: Implications for Treatment Strategies

A gender-related disparity exists in asthma morbidity and mortality, which shifts at around puberty from a male predominance to a female predominance. This is clinically reflected in the fact that asthma that occurs in childhood (childhood-onset asthma) mainly affects boys, and that asthma that occurs in adulthood (adult-onset asthma) mainly affects women. Adult-onset asthma is often non-atopic, more severe, and associated with a poorer prognosis, thus posing a marked burden to women’s health and healthcare system. Many factors have been indicated to explain this gender-related disparity, including sociocultural and environmental factors as well as biological sex differences (genetic, pulmonary and immunological factors). It has long been suggested that sex hormones may be implicated in at least these biological sex differences. Overall, the evidence remains equivocal for the role of most sex hormones in asthma pathogenesis and clinical outcomes. Well-designed randomized clinical trials are required assessing the potential preventive or therapeutic effects of hormonal contraceptives on asthma in women, thereby helping to advance the evidence to inform future practice guidelines. The mechanisms underlying the role of sex hormones in asthma are complex, and our understanding is not yet complete. Additional mechanistic studies elucidating sex hormone signaling pathways and their interactions involved in the pathogenesis and clinical manifestations of asthma will help to identify potential sex hormone-driven asthma endotypes and novel therapeutic targets, providing the basis for a more personalized asthma management strategy.

Targeting androgen signaling in ILC2s protects from IL-33-driven lung inflammation, independently of KLRG1

BACKGROUND

Allergic asthma is more severe and frequent in women than in men. In male mice, androgens negatively control group 2 innate lymphoid cell (ILC2) development and function by yet unknown mechanisms.

OBJECTIVES

We sought to investigate the impact of androgen on ILC2 homeostasis and IL-33-mediated inflammation in female lungs. We evaluated the role of androgen receptor (AR) signaling and the contribution of the putative inhibitory receptor killer cell lectin-like receptor G1 (KLRG1).

METHODS

Subcutaneous pellets mimicking physiological levels of androgen were used to treat female mice together with mice expressing a reporter enzyme under the control of androgen response elements and mixed bone marrow chimeras to assess the cell-intrinsic role of AR activation within ILC2s. We generated KLRG1-deficient mice.

RESULTS

We established that lung ILC2s express a functionally active AR that can be in vivo targeted with exogenous androgens to negatively control ILC2 homeostasis, proliferation, and function. Androgen signaling upregulated KLRG1 on ILC2s, which inhibited their proliferation on E-cadherin interaction. Despite evidence that KLRG1 impaired the competitive fitness of lung ILC2s during inflammation, KLRG1 deficiency neither alters in vivo ILC2 numbers and functions, nor did it lead to hyperactive ILC2s in either sexes.

CONCLUSIONS

AR agonists can be used in vivo to inhibit ILC2 homeostatic numbers and ILC2-dependent lung inflammation through cell-intrinsic AR activation. Although androgen signals in ILC2s to upregulate KLRG1, we demonstrate that KLRG1 is dispensable for androgen-mediated inhibition of pulmonary ILC2s.

Role of Sex Hormones at Different Physiobiological Conditions and Therapeutic Potential in MBD2 Mediated Severe Asthma

Sex hormone has become a “hot topic” to evaluate the hormonal therapeutic potential in severe asthma. Th17 cell is one of the main influencing factors involved in the pathogenesis of severe asthma, hence also called as kernel of severe asthma, and Th17 subtype of non-T2 asthma is less responsive (resistance) to inhaled corticosteroid (ICS), so severe in nature. Methyl-CpG binding domain protein 2 (MBD2) is overexpressed and regulates the Th17 differentiation, showing the possibility of therapeutic target in treating Th17 mediated severe asthma. Sex hormone fluctuates at the different physiobiological conditions of the human body and affects the asthma pathobiology showing its role in asthma prevalence, severity, remission, and therapy. This review briefly overviews the sex hormones, their influence in asthma at the different physiobiological conditions of human body, and MBD2 severe asthma connection with the possible therapeutic potential of sex steroids in MBD2 mediated Th17 predominant severe asthma. Male sex hormone tends to show a beneficial effect and possibly downregulates the expression of Th17 cells via regulating MBD2 through a mechanism distinct from corticosteroid treatment and guides us towards discovery of new therapeutic agent, reduces the asthma-related complications, and promotes long-term survival by lowering the risk of therapy-resistant issues of old age severe asthma.

Associations of Exposure to Nitrogen Oxides with Prevalent Asthma and Other Atopic Diseases in Israel

Childhood exposure to nitrogen oxides (NOx) is considered a risk factor for the onset of asthma. However, associations of this exposure with other atopic diseases and factors that modify this association are less clear. We aimed to study associations between exposure to NOx and the prevalence of atopic diseases in Israeli adolescents using a cross-sectional design. The study population comprised all Israeli-born adolescents whose medical status was evaluated for mandatory military recruitment during 1967–2017 (n = 2,523,745), of whom 5.9% had prevalent asthma. We based the exposure assessments on a land-use regression model and estimated associations using multivariable logistic regression models. Across all periods, mean exposure to NOx from birth to adolescence was associated with prevalent asthma at the examination in a dose-response manner, with an odds ratio for the upper quintile of 1.61 (95% CI: 1.56–1.67), in comparison to the lowest quintile. Associations were stronger in males and in lower socioeconomic strata. We found the strongest associations for asthma with comorbid rhinitis, with an almost twofold increase in the odds of upper versus lower quintile of exposure (odds ratio = 1.96, 95% CI: 1.82–2.11). Rhino-conjunctivitis and allergic atopic dermatitis suggested a possible threshold level with NOx. Capsule Summary: Research indicates that half of the global population will suffer from an allergic condition at some point in life. Childhood exposure to nitrogen oxides is a risk factor for the onset of asthma. The association between exposure and allergic diseases other than asthma is unclear. We demonstrate a strong, dose-response relationship between exposure and a group of allergic outcomes, using data comprising 2.5 million subjects over 50 years. The large health benefits from clean air should motivate governments to prioritize mitigation measures.

Sex, Cells, and Asthma

There are marked sex differences in asthma prevalence and severity. Sex hormones play a central role in these sex biases and directly interact with multiple key cells involved in the pathogenesis of asthma. Here we review the known effects of estrogen, progesterone, and testosterone on airway epithelial cells, airway smooth muscle cells, the mononuclear phagocyte system, innate lymphoid cells, eosinophils, mast cells, T cells, and B cells, all in the context of asthma. Furthermore, we explore unresolved clinical questions, such as the role of sex hormones in the link between asthma and obesity.

Predicting Treatment Outcomes Using Explainable Machine Learning in Children with Asthma

Asthma in children is a heterogeneous disease manifested by various phenotypes and endotypes. The level of disease control, as well as the effectiveness of anti-inflammatory treatment, is variable and inadequate in a significant portion of patients. By applying machine learning algorithms, we aimed to predict the treatment success in a pediatric asthma cohort and to identify the key variables for understanding the underlying mechanisms. We predicted the treatment outcomes in children with mild to severe asthma (N = 365), according to changes in asthma control, lung function (FEV1 and MEF50) and FENO values after 6 months of controller medication use, using Random Forest and AdaBoost classifiers. The highest prediction power is achieved for control- and, to a lower extent, for FENO-related treatment outcomes, especially in younger children. The most predictive variables for asthma control are related to asthma severity and the total IgE, which were also predictive for FENO-based outcomes. MEF50-related treatment outcomes were better predicted than the FEV1-based response, and one of the best predictive variables for this response was hsCRP, emphasizing the involvement of the distal airways in childhood asthma. Our results suggest that asthma control- and FENO-based outcomes can be more accurately predicted using machine learning than the outcomes according to FEV1 and MEF50. This supports the symptom control-based asthma management approach and its complementary FENO-guided tool in children. T2-high asthma seemed to respond best to the anti-inflammatory treatment. The results of this study in predicting the treatment success will help to enable treatment optimization and to implement the concept of precision medicine in pediatric asthma treatment.

T2-"Low" Asthma: Overview and Management Strategies

Although the term "asthma" has been applied to all patients with airway lability and variable chest symptoms for centuries, phenotypes of asthma with distinct clinical and molecular features that may warrant different treatment approaches are well recognized. Patients with type 2 (T2)-"high" asthma are characterized by upregulation of T2 immune pathways (ie, IL-4 and IL-13 gene sets) and eosinophilic airway inflammation, whereas these features are absent in patients with T2-"low" asthma and may contribute to poor responsiveness to corticosteroid treatment. This review details definitions and clinical features of T2-"low" asthma, potential mechanisms and metabolic aspects, pediatric considerations, and potential treatment approaches. Priority research questions for T2-"low" asthma are also discussed.

Testosterone-to-estradiol ratio and lung function in a prospective study of Puerto Rican youth

BACKGROUND

Age- and sex-related differences in asthma may be due to changes in sex hormone levels.

OBJECTIVE

To evaluate whether a change in free testosterone or free testosterone-to-estradiol ratio is associated with changes in lung function and eosinophils in the Puerto Rican youth.

METHODS

We tested for the association between the change in sex hormone levels and change in lung function or change in eosinophils in a prospective study of 317 children (with and without asthma) followed up from ages 6 to 14 years to ages 10 to 20 years (146 females, 171 males) in San Juan, Puerto Rico. Serum levels of testosterone, estradiol, sex hormone-binding globulin, and progesterone were measured at 2 study visits, approximately 4.9 years apart. Using testosterone and sex hormone-binding globulin levels, we derived free testosterone and the free testosterone-to-estradiol ratio. Multivariable linear regression was used for the analysis of change in lung function and eosinophils, conducted separately by sex.

RESULTS

In girls, each quartile increment in the free testosterone-to-estradiol ratio was associated with a 2.03% increment in percent predicted forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) between study visits. In males, each quartile increment in the free testosterone-to-estradiol ratio was associated with a 3.27% increment in percent predicted FEV₁ and a 1.81% increment in percent predicted FEV₁/FVC between study visits. In girls with asthma, an increased free testosterone-to-estradiol ratio was significantly associated with decreased eosinophils between visits (P=0.03).

CONCLUSION

In Puerto Rican youth, increased free testosterone-to-estradiol ratio over time was associated with an increased FEV₁/FVC in both sexes, and with an increased FEV₁ in males.

The impact of obesity on immune function in pediatric asthma

PURPOSE OF REVIEW

Pediatric obese asthma is a complex disease that remains poorly understood. The increasing worldwide incidence of both asthma and obesity over the last few decades, their current high prevalence and the challenges in treating obese asthmatic patients all highlight the importance of a better understanding of the pathophysiological mechanisms in obese asthma. While it is well established that patients with obesity are at an increased risk of developing asthma, the mechanisms by which obesity drives the onset of asthma, and modifies existing asthma, remain unclear. Here, we will focus on mechanisms by which obesity alters immune function in asthma.

RECENT FINDINGS

Lung parenchyma has an altered structure in some pediatric obese asthmatics, known as dysanapsis. Central adiposity is linked to reduced pulmonary function and a better predictor of asthma risk in children than BMI. Obesity in young children is associated with an increased risk of developing asthma, as well as early puberty, and hormonal alterations are implicated in obese asthma. Obesity and asthma each yield immunometabolic dysregulation separately and we are learning more about alterations in these pathways in pediatric obese asthma and the potential impact of bariatric surgery on those processes.

SUMMARY

The recent progress in clarifying the connections between childhood obesity and asthma and their combined impacts on immune function moves us closer to the goals of improved understanding of the pathophysiological mechanisms underpinning obese asthma and improved therapeutic target selection. However, this common inflammatory disease remains understudied, especially in children, and much remains to be learned.

Does the use of inhaled corticosteroids in asthma benefit lung function in the long-term? A systematic review and meta-analysis

While asthma is known to be associated with an increased risk of progressive lung function impairments and fixed airflow obstruction, there is ongoing debate on whether inhaled corticosteroids (ICS) modify these long-term risks. Searches were performed of the PubMed, Embase and CENTRAL databases up to 22 July 2019 for studies with follow-up ≥1 year that investigated the effects of maintenance ICS on changes in lung function in asthma.Inclusion criteria were met by 13 randomised controlled trials (RCTs) (n=11 678) and 11 observational studies (n=3720). Median (interquartile range) follow-up was 1.0 (1-4) and 8.4 (3-28) years, respectively. In the RCTs, predominantly in individuals with mild asthma, ICS use was associated with improved pre-bronchodilator (BD) forced expiratory volume in 1 s (FEV1) across all age groups (2.22% predicted (95% CI 1.32-3.12), n=8332), with similar estimates of strength in association for children and adults. Improvements in post-BD FEV1 were observed in adults (1.54% (0.87-2.21), n=3970), but not in children (0.20% (-0.49-0.90), n=3924) (subgroup difference, p=0.006). Estimates were similar between smokers and nonsmokers. There were no RCT data on incidence of fixed airflow obstruction. In the observational studies, ICS use was associated with improved pre-BD FEV1 in children and adults. There were limited observational data for post-BD outcomes.In patients with mild asthma, maintenance ICS are associated with modest, age-dependent improvements in long-term lung function, representing an added benefit to the broader clinical actions of ICS in asthma. There is currently insufficient evidence to determine whether treatment reduces incidence of fixed airflow obstruction in later life.

Trends in School Attendance for Low-Income Children with Chronic Health Conditions: Results from a Randomized Controlled Trial

BACKGROUND

In this study, we aimed to determine how school attendance changed over time for children on Medicaid with chronic health conditions enrolled in a comprehensive care coordination program called Coordinated HEalthcare for Complex Kids (CHECK).

METHODS

Medicaid beneficiaries from one managed care organization were randomized into 2 arms: CHECK program services or usual care. The final sample was 1322.

RESULTS

The mean age was 10.9 (SD = 3.7) years old and children were mostly non-Hispanic Black (62.6%) or Hispanic (34.9%). The median school attendance at baseline was 94.9% (IQR 88.9, 97.9); over one-fourth of children (28.4%) were chronically absent. School attendance was not associated with race/ethnicity, risk level, and health condition. In a model including a significant time/grade interaction, school attendance increased over time for children in pre-kindergarten (OR = 1.52, 95% CI: 1.38, 1.68; p < .001) and kindergarten to 5th grade (OR = 1.21, 95% CI: 1.17, 1.26; p < .001), and decreased for children in 6th to 8th grade (OR = 0.80, 95% CI: 0.77, 0.83; p < .001). No differences were seen in school attendance or chronic absenteeism associated with enrollment in the CHECK program.

CONCLUSIONS

School attendance improved for most of the low-income children with chronic health conditions in our cohort, except for children in middle school.

A novel locus for exertional dyspnoea in childhood asthma

Most children diagnosed with asthma have respiratory symptoms such as cough, dyspnoea and wheezing, which are also important markers of overall respiratory function. A decade of genome-wide association studies (GWAS) have investigated genetic susceptibility to asthma itself, but few have focused on important respiratory symptoms that characterise childhood asthma.Using whole-genome sequencing (WGS) data for 894 asthmatic trios from a Costa Rican cohort, we performed family-based association tests (FBATs) to assess the association between genetic variants and multiple asthma-relevant respiratory phenotypes: cough, phlegm, wheezing, exertional dyspnoea and exertional chest tightness. We tested whether genome-wide significant associations were replicated in two additional studies: 1) 286 asthmatic trios from the Childhood Asthma Management Program (CAMP), and 2) 2691 African American current or former smokers from the COPDGene study.In the 894 Costa Rican trios, we identified a genome-wide significant association (p=2.16×10-9) between exertional dyspnoea and the single nucleotide polymorphism (SNP) rs10165869, located on chromosome 2q37.3, that was replicated in the CAMP cohort (p=0.023) with the same direction of association (combined p=3.28×10-10). This association was not found in the African American participants from COPDGene. We also found suggestive evidence for an association between SNP rs10165869 and the atypical chemokine receptor 3 (ACKR3).Our finding encourages the secondary association analysis of a wider range of phenotypes that characterise respiratory symptoms in other airway diseases/studies.

Heterogeneity of Childhood Asthma in Korea: Cluster Analysis of the Korean Childhood Asthma Study Cohort

PURPOSE

Asthma is a heterogeneous airway disease occurring in children, and it has various clinical phenotypes. A clear differentiation of the clinical phenotypes can provide better asthma management and prediction of asthma prognosis. Little is currently known about asthma phenotypes in Korean children. This study was designed to identify asthma phenotypes in school-aged Korean children.

METHODS

This study enrolled 674 children with physician-diagnosed asthma from the Korean childhood Asthma Study (KAS) cohort. The physicians verified the relevant histories of asthma and comorbid diseases, as well as airway lability and hyper-responsiveness from the results of pulmonary function tests and bronchial provocation tests. Questionnaires regarding the participants' baseline characteristics, their environment and self-rating of asthma control were collected at the time of enrollment. Laboratory tests were performed to assess allergy and airway inflammation. Children with asthma were classified by hierarchical cluster analysis.

RESULTS

Of the 674 patients enrolled from the KAS cohort, 447 were included in the cluster analysis. Cluster analysis of these 447 children revealed 4 asthma phenotypes: cluster 1 (n = 216, 48.3%) which was characterized by male-dominant atopic asthma; cluster 2 (n = 79, 17.7%) which was characterized by early-onset atopic asthma with atopic dermatitis; cluster 3 (n = 47, 10.5%) which was characterized by puberty-onset, female-dominant atopic asthma with the low lung function; and cluster 4 (n = 105, 23.5%) which was characterized by early-onset, non-atopic dominant asthma.

CONCLUSIONS

The asthma phenotypes among Korean children can be classified into 4 distinct clusters. Long-term follow-up with these phenotypes will be needed to define their prognosis and response to treatment.

Prevalence and Risk Factors of Asthma in Preschool Children in Shanghai, China: A Cross-Sectional Study

BACKGROUND

Previous studies have shown the increasing prevalence of childhood asthma around the world as well as in China. Nevertheless, little is known about the epidemiology of asthma in preschool children. Thus, the present study investigated the prevalence and severity of asthma in Shanghai, China, and identified related risk factors for asthma in children at the age of 3-6.

METHODS

Information was obtained through the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Risk factor analysis was carried out using univariate and multivariate logistic regression. The odds ratio (OR)/adjusted odds ratio (aOR) and the 95% confidence interval (CI) were determined.

RESULTS

A total of 6,183 children (3,165 boys and 3,018 girls) covering 12 communities were included in our study, with an average age of 4.2 ± 0.7 years. The prevalence of ever asthma, current asthma, and physician-diagnosed asthma was 16.0, 11.2, and 5.3%, respectively. Parental allergic history, including rhinitis and asthma, was significantly associated with asthma symptoms. The strongest association with current asthma was paternal asthma (aOR = 5.91, 95% CI 3.87-9.01), and maternal asthma had the second strongest association with current asthma (3.85; 2.40-6.17). Among personal factors, allergic rhinitis history, eczema history, food allergy history, and antibiotic use in the first year of life were significantly associated with current asthma (aOR = 1.89, 95% CI 1.52-2.34; aOR = 1.34, 95% CI 1.09-1.64; aOR = 1.68, 95% CI 1.37-2.06; aOR = 1.53, 95% CI 1.25-1.87, respectively). More than once paracetamol use per year and per month were associated with current asthma in a dose-response manner. Additionally, female sex was an independent protective factor for ever asthma (0.82; 0.70-0.96). Among environmental factors, dampness or mildew at home was an independent risk factor for ever asthma (1.50; 1.15-1.97) and current asthma (1.63; 1.21-2.19). Floor heating system was significantly associated with ever asthma (1.57; 1.25-1.98) and current asthma (1.36; 1.04-1.78). Furthermore, dampness or mildew, infrequent house cleaning, and truck traffic in residential streets were significantly associated with asthma symptoms only in old communities, while paracetamol use in the first year of life and flooring materials were significant factors only in new communities.

CONCLUSION

The prevalence of asthma has increased among preschool children in Shanghai over the past three decades. The identified risk factors indicated the combined effects of genetic, personal, and environmental factors on asthma symptoms. Differentiated strategies should be taken for preventing asthma in old and new communities.

Recurrent wheezing after bronchiolitis caused by respiratory syncytial virus in children younger than 3 years: A 1-year follow-up study

We analysis the frequency and risk factors of wheezing in infants. We chose children with initial wheezing before 3 years of age who were hospitalized for medical treatment. Wheezing frequency was determined by follow-up at 1 week, 1 month, 3 months, 6 months, and 1 year. Information such as birth status, age, sex, preterm, mode of delivery, birth order, eczema history, personal allergy history, family allergy history, passive smoking, and place of residence (urban/rural) was collected. Total serum IgE level, serum allergen testing, routine blood tests, C-reactive protein level, procalcitonin level, respiratory pathogens tests, sputum culture, chest radiography or computed tomography were performed in all patients. The correlation between each factor and wheezing recurrence was evaluated. A total of 259 children were included in the study. They were divided into single recurrence, multiple recurrences, and no recurrence groups. The recurrence rate of wheezing was 56.8% (30.5% had a single recurrence and 26.3% had 2 or more recurrences). The percentage of children with a personal allergy history in the multiple recurrences group was significantly higher than in the single recurrence and no recurrence groups ( P = 0.031 and 0.008, respectively). The age of the children in the multiple recurrences group was significantly lower than that in the single recurrence group ( P < 0.001). Clinical severity scores were higher in the multiple recurrences group than in the single recurrence and no recurrence groups ( P = 0.002 and <0.001, respectively). Most children did not experience multiple recurrent wheezing. Children with young age, serious condition, and allergic constitution were prone to recurrent wheezing.

Effectiveness of Pediatric Asthma Pathways in Community Hospitals: A Multisite Quality Improvement Study

Pathways guide clinicians through evidence-based care of specific conditions. Pathways have been demonstrated to improve pediatric asthma care, but mainly in studies at tertiary children's hospitals. Our global aim was to enhance the quality of asthma care across multiple measures by implementing pathways in community hospitals.

Methods

This quality improvement study included children ages 2-17 years with a primary diagnosis of asthma. Data were collected before and after pathway implementation (total 28 mo). Pathway implementation involved local champions, educational meetings, audit/feedback, and electronic health record integration. Emergency department (ED) measures included severity assessment at triage, timely systemic corticosteroid administration (within 60 mins), chest radiograph (CXR) utilization, hospital admission, and length of stay (LOS). Inpatient measures included screening for secondhand tobacco and referral to cessation resources, early administration of bronchodilator via metered-dose inhaler, antibiotic prescription, LOS, and 7-day readmission/ED revisit. Analyses were done using statistical process control.

Results

We analyzed 881 ED visits and 138 hospitalizations from 2 community hospitals. Pathways were associated with increases in the proportion of children with timely systemic corticosteroid administration (Site 1: 32%-57%, Site 2: 62%-75%) and screening for secondhand tobacco (Site 1: 82%-100%, Site 2: 54%-89%); and decreases in CXR utilization (Site 1: 44%-29%), ED LOS (Site 1: 230-197 mins), and antibiotic prescription (Site 2: 23%-3%). There were no significant changes in other outcomes.

Conclusions

Pathways improved pediatric asthma care quality in the ED and inpatient settings of community hospitals.

Pharmacotherapeutic management of asthma in pregnancy and the effect of sex hormones

INTRODUCTION

Asthma is a common medical condition that can frequently affect pregnancy, and thus optimal management of asthma in pregnancy is important for both mother and baby. This article reviews recent developments of asthma pharmacotherapy and provides emerging data on the safety of asthma controller medications and biological therapies in pregnancy. The authors highlight the clinical outcomes of asthma during pregnancy, and summarize emerging new data related to the influence of sex hormones and fetal sex on asthma severity.

AREAS COVERED

This review of asthma pharmacotherapy during pregnancy examines the recent guidelines and reports the most pertinent publications on safety data and asthma management.

EXPERT OPINION

Asthma management during pregnancy follows the same principles as that of non-pregnant asthma. The available data for most asthma medications are reassuring, however there is a lack of adequate safety data available because pregnant women are generally excluded from clinical trials. More clarity is needed in guidelines regarding the management of asthma in pregnancy, and high-quality randomized control trials are required to strengthen the evidence base and inform future guidelines. In particular, safety studies examining biological therapies in pregnant women with severe asthma are needed.

Understanding the Interplay Between Health Disparities and Epigenomics

Social epigenomics has emerged as an integrative field of research focused on identification of socio-environmental factors, their influence on human biology through epigenomic modifications, and how they contribute to current health disparities. Several health disparities studies have been published using genetic-based approaches; however, increasing accessibility and affordability of molecular technologies have allowed for an in-depth investigation of the influence of external factors on epigenetic modifications (e.g., DNA methylation, micro-RNA expression). Currently, research is focused on epigenetic changes in response to environment, as well as targeted epigenetic therapies and environmental/social strategies for potentially minimizing certain health disparities. Here, we will review recent findings in this field pertaining to conditions and diseases over life span encompassing prenatal to adult stages.

Are We Meeting the Promise of Endotypes and Precision Medicine in Asthma?

While the term asthma has long been known to describe heterogeneous groupings of patients, only recently have data evolved which enable a molecular understanding of the clinical differences. The evolution of transcriptomics (and other 'omics platforms) and improved statistical analyses in combination with large clinical cohorts opened the door for molecular characterization of pathobiologic processes associated with a range of asthma patients. When linked with data from animal models and clinical trials of targeted biologic therapies, emerging distinctions arose between patients with and without elevations in type 2 immune and inflammatory pathways, leading to the confirmation of a broad categorization of type 2-Hi asthma. Differences in the ratios, sources, and location of type 2 cytokines and their relation to additional immune pathway activation appear to distinguish several different (sub)molecular phenotypes, and perhaps endotypes of type 2-Hi asthma, which respond differently to broad and targeted anti-inflammatory therapies. Asthma in the absence of type 2 inflammation is much less well defined, without clear biomarkers, but is generally linked with poor responses to corticosteroids. Integration of "big data" from large cohorts, over time, using machine learning approaches, combined with validation and iterative learning in animal (and human) model systems is needed to identify the biomarkers and tightly defined molecular phenotypes/endotypes required to fulfill the promise of precision medicine.

New Perspectives on Difficult Asthma; Sex and Age of Asthma-Onset Based Phenotypes

BACKGROUND

Asthma is a diverse condition that differs with age and sex. However, it remains unclear how sex, age of asthma onset, and/or their interaction influence clinical expression of more problematic adult "difficult" asthma.

OBJECTIVES

To better understand the clinical features of difficult asthma within a real-world clinical setting using novel phenotypic classification, stratifying subjects by sex and age of asthma onset.

METHODS

Participants in a longitudinal difficult asthma clinical cohort study (Wessex AsThma CoHort of difficult asthma; WATCH), United Kingdom (n = 501), were stratified into 4 difficult asthma phenotypes based on sex and age of asthma onset (early <18 years or adult ≥18 years) and characterized in relation to clinical and pathophysiological features.

RESULTS

The cohort had more female participants (65%) but had similar proportions of participants with early- or adult-onset disease. Early-onset female disease was commonest (35%), highly atopic, with good spirometry and strong associations with some physical comorbidities but highest psychophysiologic comorbidities. Adult-onset females also had considerable psychophysiologic comorbidities and highest obesity, and were least atopic. Amongst male subjects, proportionately more had adult-onset disease. Early-onset male disease was rarest (14%) but associated with worst lung function, high smoking, atopy, and fungal sensitization. Despite shortest disease duration, adult-onset males had highest use of maintenance oral corticosteroid, poor lung function, and highest fractional exhaled nitrogen oxide in spite of highest smoking prevalence.

CONCLUSIONS

This study shows that sex, age of asthma onset, and their interactions influence different clinical manifestations of difficult asthma and identifies a greater risk for lung function loss and oral corticosteroid dependence associated with smoking in adult-onset male subjects.

Timing of Maternal Asthma Diagnosis in Relation to Adverse Perinatal Outcomes

BACKGROUND

It is unclear if asthma diagnosed during pregnancy puts the fetus at a higher risk of poor perinatal outcomes than pre-existing asthma.

OBJECTIVE

To assess if the risks of prematurity, major malformations, and small-for-gestational age (SGA) are higher in women with asthma diagnosed during versus pre-pregnancy.

METHODS

We retrospectively analyzed a cohort of pregnant women aged ≥15 years with and without incident asthma, constructed from health administrative databases. Follow-up began 24 months before pregnancy onset (cohort entry) and ended at delivery. Incident asthma was defined as a first diagnosis among those without asthma in the 8 years before cohort entry. Time was classified into pre-pregnancy and each trimester until delivery. We fit inverse probability weighted Poisson models to estimate marginal relative risks (RRs) for prematurity (delivery <37th week), major malformations, and SGA (birth weight <10th percentile) comparing women with and without asthma, assessing the asthma timing of diagnosis interaction term via a Wald test.

RESULTS

In a cohort of 122,880 deliveries, the increased risk of prematurity, but not SGA, due to incident asthma was higher in those diagnosed during the second (RR, 1.34; 95% confidence interval [CI], 1.08-1.65; Wald P = .05) and third (RR, 1.93; 95% CI, 1.62-2.29; Wald P < .01) trimesters relative to pre-pregnancy (RR, 1.06; 95% CI, 0.98-1.15). A trend toward an increased risk of major malformations was observed in those diagnosed during the first trimester (RR, 1.18; 95% CI, 0.94-1.49; Wald P = .15) than pre-pregnancy (RR, 0.99; 95% CI, 0.92-1.07).

CONCLUSIONS

Asthma diagnosed during, versus before, pregnancy was associated with a greater prematurity risk, suggesting an important role of preconception and prenatal screening.

Test for respiratory and asthma control in preschool kids in the emergency department as a predictor of wheezing exacerbations

OBJECTIVE

The test for respiratory and asthma control in kids (TRACK score) is a standardized questionnaire tool validated to identify poor symptom control in children with stable preschool wheeze. This study determined if TRACK score measured within 5 days of an Emergency Department (ED) visit for acute wheezing predicts a subsequent wheezing exacerbation requiring an ED visit and/or treatment with systemic corticosteroids within 3 months.

METHODS

This was a single-center prospective cohort study of children aged 36 to 71 months who presented to the ED with an acute episode of wheezing and had TRACK score measured at a clinic visit within 5 days of the index ED encounter, focused on information about symptoms occurring before the onset of the current acute episode. The outcomes were the independent association of a repeat wheezing exacerbation with the overall TRACK score (primary) and with mutually uncorrelated TRACK items (secondary), adjusted for sex and atopy.

RESULTS

We enrolled 102 children; median age 52.3 (44.1, 59.9) months, 59% males. Of these, 33 (32.4%) had further wheezing exacerbations. For each 10 unit decrease in TRACK, the odds of a future exacerbation was 1.38 (95% CI, 1.10-1.75); male sex demonstrated OR, 5.13 (1.84-14.33). A model that included TRACK items reflecting more than equal to 1 awakenings for wheezing in the past 4 weeks, receipt of more than equal to 2 courses of corticosteroids in the last year and male sex was predictive of wheezing exacerbations: OR, 6.43 (2.18-19.00).

CONCLUSION

In preschoolers with acute wheezing episodes in the ED, we have identified the TRACK score components which, together with male sex, can be used to identify children at risk of future exacerbations requiring referral for specialized care. These results need to be confirmed and validated in other populations enrolled at multiple sites before they can be implemented in practice.

Sex Steroid Hormones and Asthma in a Nationwide Study of U.S. Adults

Rationale: Women have a higher burden of asthma than men. Although sex hormones may explain sex differences in asthma, their role is unclear.Objectives: To examine sex hormone levels and asthma in adults.Methods: Cross-sectional study of serum levels of free testosterone and estradiol and current asthma in 7,615 adults (3,953 men and 3,662 women) aged 18-79 years who participated in the 2013-2014 and 2015-2016 U.S. National Health and Nutrition Examination Survey. Logistic regression was used for the multivariable analysis of sex hormones and current asthma, which was conducted separately in women and men.Measurements and Main Results: Free testosterone levels in the fourth quartile were associated with lower odds of current asthma in women (odds ratio [OR] for the fourth quartile [Q4] vs. Q1, 0.56; 95% confidence interval [CI], 0.39-0.80). Given an interaction between obesity and sex hormones on current asthma, we stratified the analysis by obesity. In this analysis, elevated free testosterone (OR for Q4 vs. Q1, 0.59; 95% CI, 0.37-0.91) and estradiol (OR for Q4 vs. Q1, 0.43; 95% CI, 0.23-0.78) levels were associated with reduced odds of current asthma in obese women, and an elevated serum estradiol was associated with lower odds of current asthma in nonobese men (OR for Q4 vs. Q1, 0.44; 95% CI, 0.21-0.90).Conclusions: Our findings suggest that sex hormones play a role in known sex differences in asthma in adults. Moreover, our results suggest that obesity modifies the effects of sex hormones on asthma in adults.

Impaired Respiratory Function in Women With PCOS Compared With Matched Controls From a Population-Based Study

CONTEXT

Increased prevalence of asthma has been reported from epidemiological studies in women with polycystic ovary syndrome (PCOS).

OBJECTIVE

To investigate respiratory function in women with PCOS compared with controls in a clinical setting.

DESIGN

An 8-year clinical follow-up study including self-reported asthma diagnoses and spirometry of women with PCOS randomized to metformin or placebo during pregnancy in the original studies (the Pilot and the PregMet-study), compared with matched controls from a population-based cohort study (The HUNT Study).

SETTING

Secondary and tertiary care centers.

PARTICIPANTS

A total of 145 women with PCOS (54% of original cohort) were matched 1:3 to controls, on gender, age, and smoking-status.

MAIN OUTCOMES AND MEASURES

Self-reported doctor-diagnosed asthma (DDA), percentage of predicted forced expiratory volume in the first second of expiration (FEV1 % predicted), percentage of predicted forced vital capacity (FVC % predicted).

RESULTS

Women with PCOS reported more DDA compared with controls (19% vs 9%; P < 0.01). Spirometry indicated a combined obstructive (FEV1 % predicted, 93.7 vs 102.0; P < 0.01) and restrictive (FVC % predicted, 94.5 vs 103.7; P < 0.01) respiratory impairment in PCOS compared with controls. Metformin in pregnancy did not affect respiratory function at follow-up.

CONCLUSION

Women with PCOS reported higher prevalence of DDA compared with controls matched for age and smoking status. In addition, respiratory function was decreased, with both obstructive and restrictive components. Further insight to the underlying pathogenesis of these observations is needed.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: The PregMet study: NCT00159536. The Pilot study: NCT03259919.

17β-Estradiol affects lung function and inflammation following ozone exposure in a sex-specific manner

Inflammatory lung diseases affect men and women disproportionately, suggesting that fluctuations of circulating hormone levels mediate inflammatory responses. Studies have shown that ozone exposure contributes to lung injury and impairment of innate immunity with differential effects in men and women. Here, we hypothesized that 17β-estradiol enhances inflammation and airway hyperresponsiveness (AHR), triggered by ozone exposure, in the female lung. We performed gonadectomy and hormone treatment (17β-estradiol, 2 wk) in C57BL/6J female and male mice and exposed animals to 1 ppm of ozone or filtered air for 3 h. Twenty-four hours later, we tested lung function, inflammatory gene expression, and changes in bronchoalveolar lavage fluid (BALF). We found increased AHR and expression of inflammatory genes after ozone exposure. These changes were higher in females and were affected by gonadectomy and 17β-estradiol treatment in a sex-specific manner. Gonadectomized male mice displayed higher AHR and inflammatory gene expression than controls exposed to ozone; 17β-estradiol treatment did not affect this response. In females, ovariectomy reduced ozone-induced AHR, which was restored by 17β-estradiol treatment. Ozone exposure also increased BALF lipocalin-2, which was reduced in both male and female gonadectomized mice. Treatment with 17β-estradiol increased lipocalin-2 levels in females but lowered them in males. Gonadectomy also reduced ozone-induced expression of lung IL-6 and macrophage inflammatory protein-3 in females, which was restored by treatment with 17β-estradiol. Together, these results indicate that 17β-estradiol increases ozone-induced inflammation and AHR in females but not in males. Future studies examining diseases associated with air pollution exposure should consider the patient's sex and hormonal status.

Prevalence and clinical associations of wheezes and crackles in the general population: the Tromsø study

BACKGROUND

Wheezes and crackles are well-known signs of lung diseases, but can also be heard in apparently healthy adults. However, their prevalence in a general population has been sparsely described. The objective of this study was to determine the prevalence of wheezes and crackles in a large general adult population and explore associations with self-reported disease, smoking status and lung function.

METHODS

We recorded lung sounds in 4033 individuals 40 years or older and collected information on self-reported disease. Pulse oximetry and spirometry were carried out. We estimated age-standardized prevalence of wheezes and crackles and associations between wheezes and crackles and variables of interest were analyzed with univariable and multivariable logistic regressions.

RESULTS

Twenty-eight percent of individuals had wheezes or crackles. The age-standardized prevalence of wheezes was 18.6% in women and 15.3% in men, and of crackles, 10.8 and 9.4%, respectively. Wheezes were mostly found during expiration and crackles during inspiration. Significant predictors of expiratory wheezes in multivariable analyses were age (10 years increase - OR 1.18, 95%CI 1.09-1.30), female gender (1.45, 1.2-1.8), self-reported asthma (1.36, 1.00-1.83), and current smoking (1.70, 1.28-2.23). The most important predictors of inspiratory crackles were age (1.76, 1.57-1.99), current smoking, (1.94, 1.40-2.69), mMRC ≥2 (1.79, 1.18-2.65), SpO₂ (0.88, 0.81-0.96), and FEV₁ Z-score (0.86, 0.77-0.95).

CONCLUSIONS

Nearly over a quarter of adults present adventitious lung sounds on auscultation. Age was the most important predictor of adventitious sounds, particularly crackles. The adventitious sounds were also associated with self-reported disease, current smoking and measures of lung function. The presence of findings in two or more auscultation sites was associated with a higher risk of decreased lung function than solitary findings.

Genetic and observational evidence supports a causal role of sex hormones on the development of asthma

INTRODUCTION

Males have a higher prevalence of asthma in childhood, whereas females have a higher prevalence in adolescence and adulthood. The 'adolescent switch' observed between sexes during puberty has been hypothesised to be due to fluctuating sex hormones. Robust evidence of the involvement of sex hormones in asthma could lead to development of therapeutic interventions.

METHODS

We combine observational evidence using longitudinal data on sex hormone-binding globulin (SHBG), total and bioavailable testosterone and asthma from a subset of males (n=512) in the Avon Longitudinal Study of Parents and Children, and genetic evidence of SHBG and asthma using two-sample Mendelian randomisation (MR), a method of causal inference. We meta-analysed two-sample MR results across two large data sets, the Trans-National Asthma Genetics Consortium genome-wide association study of asthma and UK Biobank (over 460 000 individuals combined).

RESULTS

Observational evidence indicated weak evidence of a protective effect of increased circulating testosterone on asthma in males in adolescence, but no strong pattern of association with SHBG. Genetic evidence using two-sample MR indicated a protective effect of increased SHBG, with an OR for asthma of 0.86 (95% CI 0.74 to 1.00) for the inverse-variance weighted approach and an OR of 0.83 (95% CI 0.72 to 0.96) for the weighted median estimator, per unit increase in natural log SHBG. A sex-stratified sensitivity analysis suggested the protective effect of SHBG was mostly evident in females.

CONCLUSION

We report the first suggestive evidence of a protective effect of genetically elevated SHBG on asthma, which may provide a biological explanation behind the observed asthma sex discordance. Further work is required to disentangle the downstream effects of SHBG on asthma and the molecular pathways involved.

Risk factors and prognosis of recurrent wheezing in Chinese young children: a prospective cohort study

Background

Nearly all the investigations into the risk factors for wheezing and asthma were conducted in developed countries with a high prevalence rate of asthma and allergy, but the studies in developing countries are limited. In this study, we aimed to investigate the risk factors for different wheezing phenotypes in Chinese young children and to explore the prognosis of recurrent wheezing.

Methods

This cohort study contained the recruitment stage and the follow-up stage conducted by phone questionnaire survey. According to the information collected at the follow-up for wheezing episodes and remission age, our cohort was divided into transient wheezing, persistent wheezing and late-onset wheezing. The wheezing symptoms and potential risk factors were compared between these three wheezing groups.

Results

From the initial 109 participants, 78.0% completed the follow-up survey. The frequency of current wheezing at followup was significantly reduced in all three groups compared to the recruitment stage (p < 0.01). We observe a trend that the rhinovirus (RV) and respiratory syncytial virus (RSV) infection rates were higher in the persistent wheezing group, and the overall infection rates appear to be the lowest in late-onset wheezing group at recruitment. At follow-up stage, the rates of rhinitis ever and current rhinitis were both higher in the persistent wheezing (63.0%, 50.0%) and late-onset wheezing groups (88.2%, 58.8%), compared to the transient wheezing group (14.3%, 14.3%). The incidence of current wheezing episodes increased cumulatively if the participant had concomitant risk factors of rhinitis ever, aeroallergens sensitization at recruitment, either alone or together with previous RV infection at the time of recruitment.

Conclusion

While the incidence of wheezing declined overall with age, but in addition to transient wheezers, additional subsets of children manifest persistent wheeze or late onset wheeze, and moreover the risk factors for wheezing display phenotypic variability between these subgroups. Rhinitis ever and aeroallergens sensitization, either alone or together with previous RV infection, were the most significant predictors for persistent wheezing in children in an eastern environment, such as in China.

Deconstructing the sex bias in allergy and autoimmunity: From sex hormones and beyond

Men and women differ in their susceptibility to develop autoimmunity and allergy but also in their capacity to cope with infections. Mechanisms responsible for this sexual dimorphism are still poorly documented and probably multifactorial. This review discusses the recent development in our understanding of the cell-intrinsic actions of biological factors linked to sex, sex hormones and sex chromosome complement, on immune cells, which may account for the sex differences in the enhanced susceptibility of women to develop immunological disorders, such as allergic asthma or systemic lupus erythematosus (SLE). We choose to more specifically discuss the impact of sex hormones on the development and function of immune cell populations directly involved in type-2 immunity, and the role of the X-linked Toll like receptor 7 (TLR7) in anti-viral immunity and in SLE. We will also elaborate on the recent evidence demonstrating that TLR7 escapes from X chromosome inactivation in the immune cells of women, and how this may contribute to endow woman immune system with enhanced responsiveness to RNA-virus and susceptibility to SLE.

Health risk behaviors, violence exposure, and current asthma among adolescents in the United States

BACKGROUND

Asthma may worsen during adolescence, due to both health risk behaviors and psychosocial stressors commonly encountered during this life stage.

METHODS

Cross-sectional study of 24 612 high school students who participated in the 2009 and 2011 National Youth Risk Behavior Survey. Multivariable logistic regression was used to examine the relation between self-reported health risk behaviors or psychosocial stressors and current asthma. Mediation analysis was performed to assess whether depressive symptoms or suicidal behavior contribute to the link between psychosocial stressors and asthma.

RESULTS

Current asthma was reported by 13.1% of the study participants. In a multivariable analysis, female sex, obesity, shorter sleep duration, frequent soda/pop consumption, and marijuana use were each significantly associated with 14-36% increased odds of asthma. Any violent behavior (adjusted odds ratio [OR] = 1.12, 95% confidence interval [CI] = 1.02-1.24), any victimization (OR = 1.43, 95%CI = 1.29-1.58), any suicidal behavior (OR = 1.41, 95%CI = 1.22-1.64) and having felt sad or hopeless in the past year (OR = 1.57, 95%CI = 1.40-1.75) were each associated with current asthma. In a mediation analyses, having felt sad/hopeless and suicidal behaviors accounted for 21% and 14%, respectively, of the victimization-asthma association.

CONCLUSION

Potentially modifiable risk factors, including obesity, short sleep duration, frequent soda/pop consumption, and psychosocial stressors are associated with asthma in US adolescents. Promoting healthier lifestyles, as well as screening for violence exposure and treating depressive symptoms, could help reduce asthma burden in this population.

Sex Bias in Asthma Prevalence and Pathogenesis

Sex-related differences in asthma prevalence are well established and change through the reproductive phases of life. As children, boys have increased prevalence of asthma compared to girls. However, as adults, women have increased prevalence of asthma compared to men. Many factors, including genetics, environment, immunological responses, and sex hormones, affect the sex disparity associated with the development and control of asthma and other allergic diseases. Fluctuations of hormones during puberty, menstruation, pregnancy, and menopause, alter asthma symptoms and severity. In this article, we review clinical and epidemiological studies that examined the sex disparity in asthma and other allergic diseases as well as the role of sex hormones on asthma pathogenesis.