Validation of the maximum symptom day among children with asthma

The role of CD24hiCD27+ regulatory B cells in human chronic rhinosinusitis with/without nasal polyps

BACKGROUND

Regulatory B cells (Bregs) reduce allergic and autoimmune inflammation. However, their role in chronic rhinosinusitis (CRS) remains unknown. This study investigated the frequency and function of Breg subsets in the peripheral blood of patients with CRS.

METHODS

The demographic and clinical characteristics were compared among control, CRSsNP, neCRSwNP, and eCRSwNP groups. The expression of various Breg subtypes was evaluated in peripheral blood mononuclear cells (PBMCs) of patients with eosinophilic CRS with nasal polyps (eCRSwNP), non-eosinophilic CRS with nasal polyps (neCRSwNP), CRS without nasal polyps (CRSsNP). CD19+CD24hiCD27+ B cells (B10 cells) were isolated by flow cytometry, followed by RNA sequencing (RNA-seq). Finally, IL-10 secreted by B10 cells were evaluated through the intracellular stain.

RESULTS

A higher number of eosinophils in peripheral blood and nasal polyps were found in eCRSwNP compared with neCRSwNP, CRSsNP, and control groups. The frequency of B10 in the peripheral blood B cells (B10%) of patients with eCRSwNP was significantly lower than that in the neCRSwNP and control groups. B10% was negatively correlated with the quantity of tissue eosinophils, and the percentage and absolute value of peripheral blood eosinophils. The eCRSwNP, neCRSwNP and control groups had 1403 differentially expressed genes, 35 of which were identified in four highly enriched pathways. Additionally, the frequency of IL-10+B10 cells in peripheral blood was lower in patients with eCRSwNP than in the neCRSwNP and control groups.

CONCLUSION

This study is the first to reveal differences in both the quantity and IL-10 secretion of B10 cells in patients with eCRSwNP and neCRSwNP. These variations were strongly negatively associated with eosinophils in nasal polyps and peripheral blood. IL-10+B10 cells may play a key role in the pathological mechanisms of CRS, particularly the recurrence of eCRSwNP.

An Update on Patient-Reported Outcomes in Asthma

TOPIC IMPORTANCE

Patient-reported outcomes (PROs) are information provided by patients on their condition, function, well-being, or experience. Instruments to quantify PROs, called patient-reported outcome measures (PROMs), allow standardized assessment of a unique dimension of health that cannot be measured physically. Herein, we discuss how to appraise PROMs critically and provide an update on their use in asthma clinical practice and research.

REVIEW FINDINGS

Asthma-specific PROMs have been developed to measure a wide array of disease characteristics, including symptoms, medication use, exacerbations, and impairments to emotional and physical function. Some PROMs also include spirometry or expand questions to overlap with rhinitis symptoms. Use of PROMs to understand asthma control is included in management guidelines, yet real-world evidence of their effectiveness in improving asthma care remains limited. These instruments may be less accurate in characterizing patients with poorly controlled asthma and have modest correlation with exacerbation risk. Two new PROMs are highlighted, the Asthma Impairment and Risk Questionnaire as an instrument to assess asthma control that incorporates domains related to exacerbation risk and impairment, and the CompEx as a composite of daily diary reporting combined with exacerbation events as an early efficacy signal for interventional trials.

SUMMARY

PROMs are fundamental to asthma assessment. Novel instruments may improve the detection of patients at risk for poor outcomes and shorten the drug discovery pipeline. However, urgent research is needed to understand their practical utility in clinical settings.

Effect of radon exposure on asthma morbidity in the School Inner-City Asthma study

BACKGROUND

Radon may have a role in obstructive lung disease outside its known carcinogenicity. Little is known about radon's effects on asthma morbidity.

OBJECTIVE

To determine the effect of radon on fractional exhaled nitric oxide (FE NO), asthma symptom-days, and lung function in inner-city asthmatic school children.

METHODS

Two hundred ninety-nine school-aged asthmatic children enrolled in the School Inner-City Asthma Study (SICAS-1) were followed. One and two-month averaged radon was assessed using a spatiotemporal model predicting zip code-specific monthly exposures. FE NO and spirometry were measured twice during the academic year. Asthma symptoms were assessed four times during the academic year. The interaction between indoor radon exposure (Bq/m3 ) and seasonality predicting log-transformed FE NO, forced expiratory volume in 1 s (FEV1 ) % predicted, forced vital capacity (FVC) % predicted, FEV1 /FVC, and asthma symptom-days was evaluated.

RESULTS

Participants with high radon exposure had greater change in FE NO from warm to cold periods compared to low radon exposure (interaction p = 0.0013). Participants with >50th percentile radon exposure experience significant FE NO increase from warm to cold weather (β $\beta $  = 0.29 [95% confidence interval [CI]: 0.04-0.54], p = 0.0240). We report a positive association between radon 1-month moving average (incidence rate ratio [IRR] = 1.01, p = 0.0273) and 2-month moving average (IRR = 1.01, p = 0.0286) with maximum asthma symptom-days (n = 299, obs = 1167).

CONCLUSIONS

In asthmatic children, radon may be associated with increased asthma morbidity, suggesting radon may be a modifiable environmental risk factor for airway inflammation.

Association of a Housing Mobility Program With Childhood Asthma Symptoms and Exacerbations

Importance

Structural racism has been implicated in the disproportionally high asthma morbidity experienced by children living in disadvantaged, urban neighborhoods. Current approaches designed to reduce asthma triggers have modest impact.

Objective

To examine whether participation in a housing mobility program that provided housing vouchers and assistance moving to low-poverty neighborhoods was associated with reduced asthma morbidity among children and to explore potential mediating factors.

Design, Setting, and Participants

Cohort study of 123 children aged 5 to 17 years with persistent asthma whose families participated in the Baltimore Regional Housing Partnership housing mobility program from 2016 to 2020. Children were matched to 115 children enrolled in the Urban Environment and Childhood Asthma (URECA) birth cohort using propensity scores.

Exposure

Moving to a low-poverty neighborhood.

Main Outcomes

Caregiver-reported asthma exacerbations and symptoms.

Results

Among 123 children enrolled in the program, median age was 8.4 years, 58 (47.2%) were female, and 120 (97.6%) were Black. Prior to moving, 89 of 110 children (81%) lived in a high-poverty census tract (>20% of families below the poverty line); after moving, only 1 of 106 children with after-move data (0.9%) lived in a high-poverty tract. Among this cohort, 15.1% (SD, 35.8) had at least 1 exacerbation per 3-month period prior to moving vs 8.5% (SD, 28.0) after moving, an adjusted difference of -6.8 percentage points (95% CI, -11.9% to -1.7%; P = .009). Maximum symptom days in the past 2 weeks were 5.1 (SD, 5.0) before moving and 2.7 (SD, 3.8) after moving, an adjusted difference of -2.37 days (95% CI, -3.14 to -1.59; P < .001). Results remained significant in propensity score-matched analyses with URECA data. Measures of stress, including social cohesion, neighborhood safety, and urban stress, all improved with moving and were estimated to mediate between 29% and 35% of the association between moving and asthma exacerbations.

Conclusions and Relevance

Children with asthma whose families participated in a program that helped them move into low-poverty neighborhoods experienced significant improvements in asthma symptom days and exacerbations. This study adds to the limited evidence suggesting that programs to counter housing discrimination can reduce childhood asthma morbidity.

Phthalate biomarkers and associations with respiratory symptoms and healthcare utilization among low-income urban children with asthma

BACKGROUND

Phthalates are synthetic chemicals present in building materials, personal care products and other consumer goods. Limited studies link phthalates to pediatric asthma incidence; however, their effects on respiratory-related outcomes among those with pre-existing asthma remains unclear.

OBJECTIVE

We examined associations between phthalates and asthma symptoms, healthcare use, lung function, and lung inflammation among children with asthma.

METHODS

We collected repeated measures of urinary biomarkers for select phthalates and phthalate replacements (MBzP, MCINP, MCIOP, MCPP, MECPTP, MEHHTP, molar sum of DEHP biomarkers [MECPP, MEHHP, MEHP, MEOHP], MEP, MiBP, MnBP) and asthma symptoms, healthcare utilization, lung function, and inflammation among 148 predominantly low-income Black children (5-17 years) with persistent asthma every 3 months for one year. We used generalized estimating equations to assess associations between biomarker concentrations and asthma-related measures adjusting for age, sex, race/ethnicity, caregiver's education level, presence of smokers in the home, and season. We also considered co-exposures to other contaminants previously associated with asthma morbidity.

RESULTS

We observed consistent positive associations with individual DEHP biomarkers, the molar sum of DEHP, and BBzP with increased odds of asthma symptoms and with healthcare utilization (adjusted Odds Ratio for general asthma symptoms: ΣDEHP:1.49,95% Confidence Interval, CI:1.08-2.07; BBzP:1.34, CI:1.04-1.73). We observed similar associations between the DEHP phthalate replacement biomarker MEHHTP and most asthma symptoms evaluated; and with select low molecular weight phthalates (DiBP, DBP) and healthcare utilization. Results were similar when controlling for other environmental exposures (e.g., PM2.5, BPA). No associations were observed with lung function or inflammation, and overall, we did not observe consistent evidence of sexually dimorphic effects.

CONCLUSION

In the present study, we found evidence to suggest that exposure to select phthalates may be associated with asthma symptoms and healthcare utilization. These findings warrant confirmation given the high asthma burden and widespread and disparate phthalate exposures reported among select populations of color.

A response to COVID-19 school closures: The feasibility of a school-linked text message intervention as an adaptation to school-supervised asthma therapy

BACKGROUND

School-supervised asthma therapy improves asthma medication adherence and morbidity, particularly among low-income and underrepresented minority (URM) children. However, COVID-19-related school closures abruptly suspended this therapy. In response, we developed a school-linked text message intervention.

OBJECTIVE

The purpose of the study is to investigate the feasibility and acceptability of a school-linked text message intervention.

METHODS

In December 2020, children previously enrolled in school-supervised asthma therapy in Central Massachusetts were recruited into this school-linked text message intervention. We sent two-way, automated, daily text reminders in English or Spanish to caregivers of these children, asking if they had given their child their daily preventive asthma medicine. Our study team notified the school nurse if the caregiver did not consistently respond to text messages. School nurses performed weekly remote check-ins with all families. The primary outcome of the study was feasibility: recruitment, retention, and intervention fidelity. Secondarily we examined intervention acceptability and asthma health outcomes.

RESULTS

Twenty-six children (54% male, 69% Hispanic, 8% Black, 23% White, 93% Medicaid insured) and their caregivers were enrolled in the intervention with 96% participant retention at 6 months. Caregiver response rate to daily text messages was 81% over the study period. Children experienced significant improvements in asthma health outcomes. The intervention was well accepted by nurses and caregivers.

CONCLUSION

A school-linked text messaging intervention for pediatric asthma is feasible and acceptable. This simple, accessible intervention may improve health outcomes for low-income and URM children with asthma. It merits further study as a potential strategy to advance health equity.

Obesity, tidal volume, and pulmonary deposition of fine particulate matter in children with asthma

BACKGROUND

Obese children with asthma are more vulnerable to air pollution, especially fine particulate matter (PM_2.5), but reasons are poorly understood. We hypothesised that differences in breathing patterns (tidal volume, respiratory rate and minute ventilation) due to elevated body mass index (BMI) may contribute to this finding.

OBJECTIVE

To investigate the association of BMI with breathing patterns and deposition of inhaled PM_2.5.

METHODS

Baseline data from a prospective study of children with asthma were analysed (n=174). Tidal breathing was measured by a pitot-tube flowmeter, from which tidal volume, respiratory rate and minute ventilation were obtained. The association of BMI z-score with breathing patterns was estimated in a multivariable model adjusted for age, height, race, sex and asthma severity. A particle dosimetry model simulated PM_2.5 lung deposition based on BMI-associated changes in breathing patterns.

RESULTS

Higher BMI was associated with higher tidal volume (adjusted mean difference (aMD) between obese and normal-range BMI of 25 mL, 95% CI 5-45 mL) and minute ventilation (aMD 453 mL·min^-1, 95% CI 123-784 mL·min^-1). Higher tidal volumes caused higher fractional deposition of PM_2.5 in the lung, driven by greater alveolar deposition. This translated into obese participants having greater per-breath retention of inhaled PM_2.5 (aMD in alveolar deposition fraction of 3.4%, 95% CI 1.3-5.5%), leading to worse PM_2.5 deposition rates.

CONCLUSIONS

Obese children with asthma breathe at higher tidal volumes that may increase the efficiency of PM_2.5 deposition in the lung. This finding may partially explain why obese children with asthma exhibit greater sensitivity to air pollution.

Neighborhoods, Caregiver Stress, and Children's Asthma Symptoms

BACKGROUND

Neighborhood and caregiver characteristics have each been linked to children's asthma outcomes, but less is known about how caregiver psychosocial functioning may explain the link between neighborhood characteristics and asthma outcomes.

OBJECTIVE

To examine associations between neighborhood safety, caregiver stress and depressive symptoms, and children's asthma outcomes, and to evaluate whether caregiver stress and depressive symptoms mediate the relationship between neighborhood safety and asthma outcomes.

METHODS

We analyzed baseline data from a prospective cohort study of the effects of a housing mobility program on children's asthma-related outcomes. Age- and sex-adjusted models evaluated associations of neighborhood safety, and caregiver stress and depressive symptoms, with children's asthma symptoms and exacerbations.

RESULTS

Participants were 140 low-income children with persistent asthma (98% Black participants; 53% males; mean age, 9.0 years) with an average of 7.1 ± 5.3 maximum symptom days per 2 weeks. Lower neighborhood safety, and higher caregiver stress and depressive symptoms, were associated with higher asthma symptoms, but not exacerbations, in adjusted models (eg, for neighborhood safety, maximum symptom days: odds ratio, 1.41; 95% CI, 1.07-1.88; for caregiver stress, maximum symptom days: odds ratio, 1.08; 95% CI, 1.01-1.15; for depressive symptoms, maximum symptom days: odds ratio, 1.05; 95% CI, 1.00-1.11). Exploratory analyses suggested that caregiver stress partially mediated associations between neighborhood safety and asthma symptoms for children in unsafe neighborhoods.

CONCLUSIONS

Neighborhood safety was associated with children's asthma symptoms independent from caregiver stress and depressive symptoms, although for children in unsafe neighborhoods, caregiver stress may partially mediate this association. Findings suggest the importance of targeting multiple systems to improve children's asthma outcomes.

Indoor Environmental Factors May Modify the Response to Mouse Allergen Reduction Among Mouse-Sensitized and Exposed Children with Persistent Asthma

BACKGROUND

Whether concomitant home exposures modify the effectiveness of mouse allergen reduction among mouse-sensitized children with asthma is unknown.

OBJECTIVE

To determine whether a lower baseline home mouse allergen level, lower particulate matter 10 μ or less (PM₁₀), and the absence of sensitization and exposure to other indoor allergens are associated with greater improvements in asthma associated with mouse allergen reduction.

METHODS

A secondary analysis of a randomized clinical trial of a home mouse allergen intervention was performed to examine the effect of 3 indoor factors on the relationship between mouse allergen reduction and a range of asthma outcomes.

RESULTS

Participants (N = 297) were predominantly minority (78% African American, 22% Hispanic) and publicly insured (88%). Higher baseline mouse allergen levels were associated with a greater response to mouse allergen reduction for several symptom and exacerbation outcomes. Lower indoor PM₁₀ levels were associated with a greater response to mouse allergen reduction for several symptom outcomes, but not exacerbation outcomes. Overall, sensitization and exposure to other indoor allergens did not appear to modify the effect of mouse allergen reduction.

CONCLUSIONS

In this population of predominantly low-income children with persistent asthma and mouse sensitization, mouse allergen reduction was associated with improvements in asthma, especially among those with high baseline mouse allergen exposure. Lower indoor PM₁₀ was associated with greater improvements in asthma symptoms.

Effect of School Integrated Pest Management or Classroom Air Filter Purifiers on Asthma Symptoms in Students With Active Asthma: A Randomized Clinical Trial

IMPORTANCE

School and classroom allergens and particles are associated with asthma morbidity, but the benefit of environmental remediation is not known.

OBJECTIVE

To determine whether use of a school-wide integrated pest management (IPM) program or high-efficiency particulate air (HEPA) filter purifiers in the classrooms improve asthma symptoms in students with active asthma.

DESIGN, SETTING, AND PARTICIPANTS

Factorial randomized clinical trial of a school-wide IPM program and HEPA filter purifiers in the classrooms was conducted from 2015 to 2020 (School Inner-City Asthma Intervention Study). There were 236 students with active asthma attending 41 participating urban elementary schools located in the Northeastern US who were randomized to IPM by school and HEPA filter purifiers by classroom. The date of final follow-up was June 20, 2020.

INTERVENTIONS

The school-wide IPM program consisted of application of rodenticide, sealing entry points, trap placement, targeted cleaning, and brief educational handouts for school staff. Infestation was assessed every 3 months, with additional treatments as needed. Control schools received no IPM, cleaning, or education. Classroom portable HEPA filter purifiers were deployed and the filters were changed every 3 months. Control classrooms received sham HEPA filters that looked and sounded like active HEPA filter purifiers. Randomization was done independently (split-plot design), with matching by the number of enrolled students to ensure a nearly exact 1:1 student ratio for each intervention with 118 students randomized to each group. Participants, investigators, and those assessing outcomes were blinded to the interventions.

MAIN OUTCOMES AND MEASURES

The primary outcome was the number of symptom-days with asthma during a 2-week period. Symptom-days were assessed every 2 months during the 10 months after randomization.

RESULTS

Among the 236 students who were randomized (mean age, 8.1 [SD, 2.0] years; 113 [48%] female), all completed the trial. At baseline, the 2-week mean was 2.2 (SD, 3.9) symptom-days with asthma and 98% of the classrooms had detectable levels of mouse allergen. The results were pooled because there was no statistically significant difference between the 2 interventions (P = .18 for interaction). During a 2-week period, the mean was 1.5 symptom-days with asthma after use of the school-wide IPM program vs 1.9 symptom-days after no IPM across the school year (incidence rate ratio, 0.71 [95% CI, 0.38-1.33]), which was not statistically significantly different. During a 2-week period, the mean was 1.6 symptom-days with asthma after use of HEPA filter purifiers in the classrooms vs 1.8 symptom-days after use of sham HEPA filter purifiers across the school year (incidence rate ratio, 1.47 [95% CI, 0.79-2.75]), which was not statistically significantly different. There were no intervention-related adverse events.

CONCLUSIONS AND RELEVANCE

Among children with active asthma, use of a school-wide IPM program or classroom HEPA filter purifiers did not significantly reduce symptom-days with asthma. However, interpretation of the study findings may need to consider allergen levels, particle exposures, and asthma symptoms at baseline.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02291302.

Obesity may enhance the adverse effects of NO2 exposure in urban schools on asthma symptoms in children

BACKGROUND

Sparse data address the effects of nitrogen dioxide (NO₂) exposure in inner-city schools on obese students with asthma.

OBJECTIVE

We sought to evaluate relationships between classroom NO₂ exposure and asthma symptoms and morbidity by body mass index (BMI) category.

METHODS

The School Inner-City Asthma Study enrolled students aged 4 to 13 years with asthma from 37 inner-city schools. Students had baseline determination of BMI percentile. Asthma symptoms, morbidity, pulmonary inflammation, and lung function were monitored throughout the subsequent academic year. Classroom NO₂ data, linked to enrolled students, were collected twice per year. We determined the relationship between classroom NO₂ levels and asthma outcomes by BMI stratification.

RESULTS

A total of 271 predominantly black (35%) or Hispanic students (35%) were included in analyses. Fifty percent were normal weight (5-84th BMI percentile), 15% overweight (≥85-94th BMI percentile), and 35% obese (≥95th BMI percentile). For each 10-parts per billion increase in NO₂, obese students had a significant increase in the odds of having an asthma symptom day (odds ratio [OR], 1.86; 95% CI, 1.15-3.02) and in days caregiver changed plans (OR, 4.24; 95% CI, 2.33-7.70), which was significantly different than normal weight students who exhibited no relationship between NO₂ exposure and symptom days (OR, 0.90; 95% CI, 0.57-1.42; pairwise interaction P = .03) and change in caregiver plans (OR, 1.37; 95% CI, 0.67-2.82; pairwise interaction P = .02). Relationships between NO₂ levels and lung function and fractional exhaled nitric oxide did not differ by BMI category. If we applied a conservative Holm-Bonferroni correction for 16 comparisons (obese vs normal weight and overweight vs normal weight for 8 outcomes), these findings would not meet statistical significance (all P > .003).

CONCLUSIONS

Obese BMI status appears to increase susceptibility to classroom NO₂ exposure effects on asthma symptoms in inner-city children. Environmental interventions targeting indoor school NO₂ levels may improve asthma health for obese children. Although our findings would not remain statistically significant after adjustment for multiple comparisons, the large effect sizes warrant future study of the interaction of obesity and pollution in pediatric asthma.