Trends in asthma prevalence and incidence in Ontario, Canada, 1996-2005: a population study

Sex-dependent regulation of mucin gene transcription and airway secretion and mechanics following intra-airway IL-13 in mice with conditional loss of club cell Creb1

Introduction: Interleukin 13 (IL-13) is an important effector molecule in allergic asthma. IL-13-mediated mucin hypersecretion requires conversion of secretoglobin-positive club cells into goblet cells through suppression of forkhead box A2 (FOXA2) and induction of SAM pointed domain containing ETS transcription factor (SPDEF). IL-13-mediated mucin hypersecretion may also include modulation of purinergic and muscarinic receptors that control basal and stimulated mucin secretion. We recently found that the transcription factor cAMP response element-binding protein (Creb1) inhibits FOXA2 and modulates mucus secretion in mice. Methods: We tested the hypothesis that loss of club cell Creb1 mitigates the pro-mucin effects of IL-13. We challenged male and female mice with conditional loss of club cell Creb1 and wild type littermates with intra-airway IL-13 or vehicle. We also studied human "club cell-like" NCI-H322 cells. Results: Loss of club cell Creb1 augmented IL-13-mediated increases in mRNA for the gel-forming mucins Muc5ac and Muc5b and prevented IL-13-mediated decreases in muscarinic 3 receptor (M3R) mRNA in male airways. In female airways, loss of club cell Creb1 reduced M3R mRNA and significantly blunted IL-13-mediated increases in purinergic receptor P2Y2 (P2ry2) mRNA but did not impact Muc5ac and Muc5b mRNA. Despite changes in mucins and secretion machinery, goblet cell density following cholinergic stimulation was not impacted by loss of club cell Creb1 in either sex. IL-13 treatment decreased basal airway resistance across sexes in mice with loss of club cell Creb1, whereas loss of club cell Creb1 augmented IL-13-mediated increases in airway elastance in response to methacholine. NCI-H322 cells displayed IL-13 signaling components, including IL-13Rα1 and IL-4Rα. Pharmacologic inhibition of CREB reduced IL-13Rα1 mRNA, whereas recombinant CREB decreased IL-4Rα mRNA. Application of IL-13 to NCI-H322 cells increased concentrations of cAMP in a delayed manner, thus linking IL-13 signaling to CREB signaling. Conclusion: These data highlight sex-specific regulation of club cell Creb1 on IL-13-mediated mucin hypersecretion and airway mechanics.

Phosphorylated p38 MAP kinase expression by leucocytes is increased in allergic humans and associated with IgE responses

Mitogen-activated protein kinases (MAPK) activate cascades that regulate cell proliferation, differentiation and death. Phosphorylated (phos-)p38 MAPK is a cell-signalling pathway associated with Th2 cytokine responses, which is required for immunoglobulin (Ig)E production. It is unknown whether MAPK are associated with IgE production. We examine the evidence linking p38 MAPK to inflammatory responses. Phos-p38, extracellular signal-related kinase (ERK) and c-JUN-n terminal (JNK) MAPK expression by blood leucocyte subsets and levels of serum Igs were measured in blood from adults with asthma and/or rhinoconjunctivitis (N = 28) and non-asthma (N = 10) (flow cytometry, microfluorenzymeimmunoassay). Peripheral blood mononuclear cells (PBMC) from allergic subjects were cultured for 10 days ± anti-CD40/recombinant IL-4 ± inhibitor of phos-P38. Culture supernatants were assayed for IgE (ELISA). Phos-p38 MAPK expression by all leucocyte subsets of allergic subjects was associated with serum IgE levels (p ≤ 0.01), after adjusting for cell counts, age, sex, race and smoking status (p ≤ 0.04). Leucocyte expression of phos-ERK and JNK did not correlate with IgE (p = 0.09-0.99). Instead, phos-ERK expression was associated with serum IgG. When PBMC from atopic subjects were cultured for 10 days with anti-CD40/rhIL-4, IgE levels were 26.2 ± 18 ng/mL. Inclusion of SB202190 (5-20 μg/mL), a specific inhibitor of phos-p38 MAPK, in culture suppressed IgE production in dose-dependent manner, with peak suppression obtained with SB202190 at 20 μg/mL (82.1% ± 11.8) (p = 0.0001), with virtually no cytotoxicity (<5%). Different MAPK pathways may be associated with IgE (p38) and IgG (ERK) responses. Phos-p38 MAPK can be a potential anti-allergy drug target.

Changes in industrial air pollution and the onset of childhood asthma in Quebec, Canada

Ambient air pollution has been associated with asthma onset and exacerbation in children. Whether improvement in air quality due to reduced industrial emissions has resulted in improved health outcomes such as asthma in some localities has usually been assessed indirectly with studies on between-subject comparisons of air pollution from all sources and health outcomes. In this study we directly assessed, within small areas in the province of Quebec (Canada), the influence of changes in local industrial fine particulate matter (PM2.5), nitrogen dioxide (NO2), and sulfur dioxide (SO2) concentrations, on changes in annual asthma onset rates in children (≤12 years old) with a longitudinal ecological design. We identified the yearly number of new cases of childhood asthma in 1282 small areas (census tracts or local community service centers) for the years 2002, 2004, 2005, 2006, and 2015. Annual average concentrations of industrial air pollutants for each of the geographic areas, and three sectors (i.e., pulp and paper mills, petroleum refineries, and metal smelters) were estimated by the Polair3D chemical transport model. Fixed-effects negative binomial models adjusted for household income were used to assess associations; additional adjustments for environmental tobacco smoke, background pollutant concentrations, vegetation coverage, and sociodemographic characteristics were conducted in sensitivity analyses. The incidence rate ratios (IRR) for childhood asthma onset for the interquartile increase in total industrial PM2.5, NO2, and SO2 were 1.016 (95% confidence interval, CI: 1.006-1.026), 1.063 (1.045-1.090), and 1.048 (1.031-1.080), respectively. Positive associations were also found with pollutant concentrations from most individual sectors. Results suggest that changes in industrial pollutant concentrations influence childhood asthma onset rates in small localities.

Sex-Specific Associations between Prenatal Exposure to Di(2-ethylhexyl) Phthalate, Epigenetic Age Acceleration, and Susceptibility to Early Childhood Upper Respiratory Infections

Di(2-ethylhexyl) phthalate (DEHP) is a common plasticizer that can affect immune system development and susceptibility to infection. Aging processes (measured as epigenetic age acceleration (EAA)) may mediate the immune-related effects of prenatal exposure to DEHP. This study's objective was to examine associations between prenatal DEHP exposure, EAA at three months of age, and the number of upper respiratory infections (URIs) from 12 to 18 months of age using a sample of 69 maternal-child pairs from a Canadian pregnancy cohort. Blood DNA methylation data were generated using the Infinium HumanMethylation450 BeadChip; EAA was estimated using Horvath's pan-tissue clock. Robust regressions examined overall and sex-specific associations. Higher prenatal DEHP exposure (B = 6.52, 95% CI = 1.22, 11.81) and increased EAA (B = 2.98, 95% CI = 1.64, 4.32) independently predicted more URIs. In sex-specific analyses, some similar effects were noted for boys, and EAA mediated the association between prenatal DEHP exposure and URIs. In girls, higher prenatal DEHP exposure was associated with decreased EAA, and no mediation was noted. Higher prenatal DEHP exposure may be associated with increased susceptibility to early childhood URIs, particularly in boys, and aging biomarkers such as EAA may be a biological mechanism. Larger cohort studies examining the potential developmental immunotoxicity of phthalates are needed.

Developmental health of Canadian kindergarten children with teacher-reported asthma between 2010 and 2015: A population-level cross-sectional study

Asthma can impact children's quality of life. It is unclear how asthma is associated with the developmental health (i.e. a broad range of skills and abilities associated with growth and development) of young children at school entry. The goals of this cross-sectional, population-level study were to: (1) investigate the association between teacher-reported asthma and children's concurrent indicators of developmental health (developmental vulnerability); and (2) explore whether school absences and functional impairments modified this association. Participants were a Canadian population-based sample of 564 582 kindergarten children (Mage = 5.71 years, SD = 0.32, 51.3 % male) with data on the Early Development Instrument (EDI) collected between 2010 and 2015. Adjusted binary logistic regressions were conducted to address the objectives. From the sample, 958 (0.2 %) children were identified as having a diagnosis of asthma. These children were absent on average 9.4 days and 53.5 % had functional impairments (vs. 6.7 days absent and 15.9 % with functional impairments in children without asthma). After controlling for demographic characteristics, children with asthma had between 1.51 and 2.42 higher odds of being developmentally vulnerable. Only the presence of functional impairments modified this relationship and only for physical health and well-being. In this large, population-based sample of Canadian kindergarten children, few teachers reported knowledge of their students' asthma diagnosis. Among teacher-reported cases, asthma was a risk factor for developmental vulnerability in the domain of physical health and well-being only. Functional impairments may therefore be more detrimental for child development at school entry than asthma alone.

Previous Ischemic Stroke Significantly Alters Stroke Risk in Newly Diagnosed Cancer Patients

BACKGROUND

Previous ischemic stroke (IS) is a risk factor for subsequent IS in the general population; it is unclear if this relationship remains true in patients with cancer. Our objective was to examine the association between previous IS and risk for future IS in individuals newly diagnosed with cancer.

METHODS

We conducted a retrospective population-based matched cohort study of newly diagnosed adult cancer patients (excluding nonmelanoma skin cancers and primary central nervous system tumors) in Ontario, Canada from 2010 to 2020; those with prior IS were matched (1:4) by age, sex, year of cancer diagnosis, cancer stage, and cancer site to those without a history of stroke. Cumulative incidence function curves were created to estimate the incidence of IS. Subdistribution adjusted hazard ratios (aHRs) and 95% CIs were calculated, where death was treated as a competing event. Multivariable analysis was adjusted for imbalanced baseline characteristics.

RESULTS

We examined 65 525 individuals with cancer, including 13 070 with a history of IS. The median follow-up duration was 743 days (interquartile range, 177-1729 days). The incidence of IS following cancer diagnosis was 261.3/10 000 person-years in the cohort with prior IS and 75.3/10 000 person-years in those without prior IS. Individuals with prior IS had an increased risk for IS after cancer diagnosis compared with those without a history (aHR, 2.68 [95% CI, 2.41-2.98]); they also had more prevalent cardiovascular risk factors. The highest risk for stroke compared with those without a history of IS was observed in the gynecologic cancer (aHR, 3.84 [95% CI, 2.15-6.85]) and lung cancer (aHR, 3.18 [95% CI, 2.52-4.02]) subgroups. The risk of IS was inversely correlated with lag time of previous stroke; those with IS 1 year before their cancer diagnosis had the highest risk (aHR, 3.68 [95% CI, 3.22-4.22]).

CONCLUSIONS

Among individuals with newly diagnosed cancer, those with IS history were almost 3× more likely to experience a stroke after cancer diagnosis, especially if the prediagnosis stroke occurred within 1 year preceding cancer diagnosis.

Villeneuve P, Kaiser DJ, Smargiassi A. The influence of urban trees and total vegetation on asthma development in children

Objective

We aimed to assess whether the influence of urban vegetation on asthma development in children (<13 years) varies by type (e.g., total vegetation, tree type, and grass) and season.

Methods

We used a cohort of all children born in Montreal, Canada, between 2000 and 2015. Children and cases were identified from linked medico-administrative databases. Exposure to residential vegetation was estimated using the Normalized Difference Vegetation Index (NDVI) for total vegetation and using the total area covered by deciduous and evergreen crowns for trees in 250 m buffers centered on residential postal codes. Seasonal variations in vegetation were modeled by setting values to zero on days outside of pollen and leaf-on seasons. Cox models with vegetation exposures, age as a time axis, and adjusted for sex, material deprivation, and health region were used to estimate hazard ratios (HR) for asthma development.

Results

We followed 352,946 children for a total of 1,732,064 person-years and identified 30,816 incident cases of asthma. While annual vegetation (total and trees) measures did not appear to be associated with asthma development, models for pollen and leaf-on seasons yielded significant nonlinear associations. The risk of developing asthma was lower in children exposed to high levels (>33,300 m2) of deciduous crown area for the leaf-on season (HR = 0.69; 95% confidence interval [CI] = 0.67, 0.72) and increased for the pollen season (HR = 1.07; 95% CI =1.02, 1.12), compared with unexposed children. Similar results were found with the Normalized Difference Vegetation Index.

Conclusion

The relationship between urban vegetation and childhood asthma development is nonlinear and influenced by vegetation characteristics, from protective during the leaf-on season to harmful during the pollen season.

Validation of adult asthma case definitions for primary care sentinel surveillance

BACKGROUND

Most asthma diagnoses and patient care take place in primary care settings. Electronic medical records (EMRs) offer an opportunity to utilize technology to improve asthma diagnosis and care. The purpose of this study was to create and validate separate case definitions for suspected and confirmed asthma in primary care EMRs, to enable surveillance, benchmarking, and quality improvement in primary care settings. The objective of this study was to develop a case definition for suspected and confirmed asthma for use in a primary care sentinel surveillance system.

METHODS

A single chart abstractor conducted a manual audit of 776 randomly selected patient charts from an academic primary care practice EMR in Kingston, Ontario. Following the single chart abstractor classification, a consensus on chart classification as "not asthma", "suspected asthma", or "confirmed asthma" was achieved between the abstractor, a family physician, and a respirologist using Canadian Thoracic Society (CTS) criteria. Case definition algorithms based on billing codes, clinical data elements and medications were applied to the site's Canadian Primary Care Sentinel Surveillance Network (CPCSSN) data for the same charts and compared to abstractor classifications to determine each algorithm's measurement properties.

RESULTS

The prevalence of suspected and confirmed asthma were 7.3% (n = 54) and 2.4% (n = 18), respectively. None of the proposed case definitions could differentiate between suspected and confirmed asthma. One algorithm consisting of billing, clinical, and medication elements had the highest Youden's Index for either suspected or confirmed asthma. The algorithm had a sensitivity of 81%, a specificity of 96%, positive predictive value of 71%, negative predictive value of 98%, and a Youden's Index of 0.77 for combined suspected or confirmed asthma cases.

CONCLUSION

An EMR case definition for suspected or confirmed adult asthma has been validated for use in CPCSSN. Implementation of this case definition will enable the development of a surveillance electronic tool (eTool) for adult asthma that can foster quality improvement.

Ascertaining asthma status in epidemiologic studies: a comparison between administrative health data and self-report

BACKGROUND

Studies have suggested that agreement between administrative health data and self-report for asthma status ranges from fair to good, but few studies benefited from administrative health data over a long period. We aimed to (1) evaluate agreement between asthma status ascertained in administrative health data covering a period of 30 years and from self-report, and (2) identify determinants of agreement between the two sources.

METHODS

We used administrative health data (1983-2012) from the Quebec Birth Cohort on Immunity and Health, which included 81,496 individuals born in the province of Quebec, Canada, in 1974. Additional information, including self-reported asthma, was collected by telephone interview with 1643 participants in 2012. By design, half of them had childhood asthma based on health services utilization. Results were weighted according to the inverse of the sampling probabilities. Five algorithms were applied to administrative health data (having ≥ 2 physician claims over a 1-, 2-, 3-, 5-, or 30-year interval or ≥ 1 hospitalization), to enable comparisons with previous studies. We estimated the proportion of overall agreement and Kappa, between asthma status derived from algorithms and self-reports. We used logistic regression to identify factors associated with agreement.

RESULTS

Applying the five algorithms, the prevalence of asthma ranged from 49 to 55% among the 1643 participants. At interview (mean age = 37 years), 49% and 47% of participants respectively reported ever having asthma and asthma diagnosed by a physician. Proportions of agreement between administrative health data and self-report ranged from 88 to 91%, with Kappas ranging from 0.57 (95% CI: 0.52-0.63) to 0.67 (95% CI: 0.62-0.72); the highest values were obtained with the [≥ 2 physician claims over a 30-year interval or ≥ 1 hospitalization] algorithm. Having sought health services for allergic diseases other than asthma was related to lower agreement (Odds ratio = 0.41; 95% CI: 0.25-0.65 comparing ≥ 1 health services to none).

CONCLUSIONS

These findings indicate good agreement between asthma status defined from administrative health data and self-report. Agreement was higher than previously observed, which may be due to the 30-year lookback window in administrative data. Our findings support using both administrative health data and self-report in population-based epidemiological studies.

Association of clinically significant obstructive sleep apnoea with risks of contracting COVID-19 and serious COVID-19 complications: a retrospective population-based study of health administrative data

RATIONALE/OBJECTIVES

Despite plausible pathophysiological mechanisms, more research is needed to confirm the relationship between obstructive sleep apnoea (OSA) and the risk of COVID-19 infection or COVID-19-related serious complications.

METHODS

We conducted a retrospective population-based cohort study using provincial health administrative data (Ontario, Canada). Adults with physician-diagnosed OSA who received positive airway pressure therapy in the 5 years prepandemic (OSA group) were propensity score matched by baseline characteristics to individuals in the general population at low risk of OSA (non-OSA group) using inverse probability of treatment weighting. Weighted HRs of (1) a positive COVID-19 test and (2) COVID-19-related emergency department (ED) visits, hospitalisations, intensive care unit (ICU) admissions and mortality, within 12 months of pandemic onset, were compared between groups. We also evaluated the impact of comorbid cardiometabolic or chronic airways disease.

RESULTS

We identified and matched 324 029 individuals in the OSA group to 4 588 200 individuals in the non-OSA group. Compared with the non-OSA group, those in the OSA group were at a greater hazard of testing positive for COVID-19 (HR=1.17, 95% CI 1.13 to 1.21), having a COVID-19-related ED visit (HR=1.62, 95% CI 1.51 to 1.73), hospitalisation (HR=1.50, 95% CI 1.37 to 1.65) or ICU admission (HR=1.53, 95% CI 1.27 to 1.84). COVID-19-related 30-day mortality was not different (HR=0.98, 95% CI 0.82 to 1.16).We found that for the OSA group, comorbid airways disease but not cardiometabolic conditions increased the hazards of COVID-19-related outcomes, including mortality.

CONCLUSION

In this large population-based study, we demonstrated that a recent diagnosis of OSA requiring treatment was associated with an increased hazard of testing positive for COVID-19 and serious COVID-19-related complications, particularly in those with co-existing chronic airways disease.

Incidence of cardiovascular disease and mortality in childhood solid organ transplant recipients: a population-based study

BACKGROUND

With improved survival among children after transplantation, our understanding of the risk for developing other comorbidities is improving, yet little is known about the long-term risk of cardiovascular events and mortality after solid organ transplantation.

METHODS

In a cohort study using health administrative data, we compared cardiovascular events in children (n = 615) with liver, lung, kidney, small bowel, or multi-organ transplant at the Hospital for Sick Children, Toronto, Canada, with asthmatic children (n = 481,697) between 1996 and 2014. Outcomes included non-fatal cardiovascular events, cardiovascular death, all-cause mortality, and a composite of non-fatal and fatal cardiovascular events. Time-stratified Cox proportional hazards models were used.

RESULTS

Among 615 children, 317 (52%) were recipients of kidneys, 253 (41%) of livers, and the remaining 45 (7%) had lung, small bowel, or multi-organ transplants. Median follow-up was 12.1 [7.2, 16.7] years. Non-fatal incident cardiovascular events were 34 times higher among solid organ transplant recipients than non-transplanted children (incidence rate ratio (IRR) 34.4, 95% CI: 25.5, 46.4). Among transplant recipients, the cumulative incidence of non-fatal and fatal cardiovascular events was 2.3% and 13.0%, 5 and 15 years after transplantation, respectively.

CONCLUSIONS

Increased rate of cardiovascular events in children after transplantation highlights the need for surveillance during transition into adulthood and beyond. A higher resolution version of the Graphical abstract is available as Supplementary information.

Patient and physician factors associated with symptomatic undiagnosed asthma or COPD

BACKGROUND

It remains unclear why some symptomatic individuals with asthma or COPD remain undiagnosed. Here, we compare patient and physician characteristics between symptomatic individuals with obstructive lung disease (OLD) who are undiagnosed and individuals with physician-diagnosed OLD.

METHODS

Using random-digit dialling and population-based case finding, we recruited 451 participants with symptomatic undiagnosed OLD and 205 symptomatic control participants with physician-diagnosed OLD. Data on symptoms, quality of life and healthcare utilisation were analysed. We surveyed family physicians of participants in both groups to elucidate differences in physician practices that could contribute to undiagnosed OLD.

RESULTS

Participants with undiagnosed OLD had lower mean pre-bronchodilator forced expiratory volume in 1 s percentage predicted compared with those who were diagnosed (75.2% versus 80.8%; OR 0.975, 95% CI 0.963-0.987). They reported greater psychosocial impacts due to symptoms and worse energy and fatigue than those with diagnosed OLD. Undiagnosed OLD was more common in participants whose family physicians were practising for >15 years and in those whose physicians reported that they were likely to prescribe respiratory medications without doing spirometry. Undiagnosed OLD was more common among participants who had never undergone spirometry (OR 10.83, 95% CI 6.18-18.98) or who were never referred to a specialist (OR 5.92, 95% CI 3.58-9.77). Undiagnosed OLD was less common among participants who had required emergency department care (OR 0.44, 95% CI 0.20-0.97).

CONCLUSIONS

Individuals with symptomatic undiagnosed OLD have worse pre-bronchodilator lung function and present with greater psychosocial impacts on quality of life compared with their diagnosed counterparts. They were less likely to have received appropriate investigations and specialist referral for their respiratory symptoms.

A cross-sectional study of community-level physician retention and hospitalization in rural Ontario, Canada

PURPOSE

Many rural communities experience poor family physician retention. We examined the association between community-level physician retention and hospitalization for all causes and ambulatory care-sensitive conditions (ACSCs) in 2017 among residents of rural communities in Ontario, Canada.

METHODS

We conducted a population-based cross-sectional study by linking administrative data from the public health insurance program in Ontario. To create the physician retention measure for each rural community, we divided the number of family physicians who worked in the community in both 2016 and 2017 by the total number of unique family physicians in the community in either year. We grouped retention level by tertile and added a fourth category, "no physician" to include communities that did not have any residing physicians in either 2016 or 2017. Outcomes were all-cause hospitalization and ACSC hospitalization between April 1, 2017 and March 31, 2018.

FINDINGS

Among 1,436,794 rural residents, there were 93,752 all-cause hospitalizations and 8,691 ACSC hospitalizations in 2017. After controlling for other predictors, compared to residents in low-retention communities, residents of medium- and high-retention communities were 0.888 (95% CI: 0.868-0.909) and 0.937 (95% CI: 0.915-0.960) times as likely to have all-cause hospitalization, and residents of high-retention communities were 0.918 (95% CI: 0.858-0.981) times as likely to have ACSC hospitalization in 2017.

CONCLUSIONS

Community-level physician retention is significantly associated with all cause and ACSC hospitalization in rural communities in Ontario, and may serve as an alternate measure to assess the impact of disrupted continuity of care.

Association of weight-adjusted-waist index with asthma prevalence and the age of first asthma onset in United States adults

OBJECTIVE

The objective of this study was to assess whether the weight-adjusted-waist index(WWI) is associated with the prevalence of asthma and age when first asthma onset appears in US adults.

METHODS

For analysis we selected participants from the National Health and Nutrition Examination Survey(NHANES)database between 2001 and 2018. A dose-response curve was calculated using logistic regression,subgroup analysis,and a dose-response curve.

RESULTS

The study included 44480 people over the age of 20,including 6061 reported with asthma, and the increase in asthma prevalence was 15% associated with each unit increase in the WWI, after adjusting for all confounders(odds ratio(OR)=1.15,95% CI:1.11,1.20). The sensitivity analysis was performed by trichotomizing the WWI, and compared to the lowest tertile, the highest tertile WWI group displayed a 29% increase in asthma prevalence(OR=1.29,95% CI:1.19,1.40). A nonlinear correlation was found between the WWI index and the risk of asthma onset, with a threshold saturation effect indicating an inflection point of 10.53 (log-likelihood ratio test, P<0.05), as well as a positive linear correlation with age at first asthma onset.

CONCLUSIONS

A higher WWI index was associated with an increased prevalence of asthma and an older age of first asthma onset.

Optimizing pediatric asthma education using virtual platforms during the COVID-19 pandemic

Background

We compared patient and caregiver knowledge and confidence for managing asthma, and participant experiences when comprehensive asthma education was delivered in person versus in the virtual setting.

Methods

We performed a multi-methods study using structured surveys and qualitative interviews to solicit feedback from patients and caregivers following participation in a comprehensive asthma education session between April 2018 and October 2021. We compared participant knowledge and confidence for managing asthma as well as user experience when the education was attended in-person or virtually. Quantitative responses were summarized descriptively, and qualitative feedback was analyzed for major themes.

Results

Of 100 caregivers/patients who completed post education satisfaction surveys and interviews, 52 attended in person and 48 virtually, with the mean age of patients being 6.7 years (range: 1.2–17.0). Participant reported gains in knowledge and confidence for asthma management were not different between groups and 65.2% preferred attending virtual asthma education. The majority of participants described virtual education as a safer modality that was more convenient and accessible.

Conclusions

We demonstrated the successful implementation of a novel, virtual asthma education program for patients and caregivers of children with asthma. Both virtual and in-person delivered asthma education were equally effective for improving perceived knowledge and confidence for asthma self-management and virtual education was considered safer, more convenient and accessible. Virtual asthma education offers an attractive and effective option for improving the reach of quality asthma education programs and may allow more children/patients to benefit.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-022-00713-y.

A longitudinal analysis of early lung function trajectory in survivors of childhood Hodgkin lymphoma

BACKGROUND

Childhood Hodgkin lymphoma survivors suffer from long-term effects decades after treatment completion with a prevalence of pulmonary dysfunction of up to 65.2%.

AIMS

This study explored the early trajectory of pulmonary function in pediatric cancer patients with Hodgkin lymphoma who received pulmonary toxic therapy.

METHODS AND RESULTS

In this single-center, 20-year retrospective cohort study, we included patients who were <18 years old at diagnosis of Hodgkin lymphoma between January 1994 and December 2014, and received bleomycin or thoracic radiation. We measured pulmonary function and reported on percent predicted values for forced expiratory volume in 1 s, total lung capacity, and diffusing capacity of the lungs. We used linear mixed models to identify the association of clinical factors with longitudinal changes in lung function at time points before and after treatment completion. Of 80 children who met inclusion criteria, all were treated with bleomycin, and 83.8% received thoracic radiation. More than half (51.2%) of patients had any abnormalities in lung function measures during the study observation period which averaged 24.2 months (±31.1SD). Females, younger age at diagnosis and treatment with radiation were associated with lower lung function measurements at various time points. While the majority of children experienced a recovery of their lung function within 1-2 years after treatment completion, some children with these risk factors did not.

CONCLUSION

Pulmonary function abnormalities begin early in children treated for Hodgkin lymphoma. While the majority of children demonstrate a slow and continuous improvement in lung function back to baseline over time, we recommend routine asymptomatic screening of pulmonary function in certain childhood cancer survivors, particularly females, those diagnosed young and patients who received radiation therapy.

Facilitators and barriers to the implementation of the Primary Care Asthma Paediatric Pathway: a qualitative analysis

OBJECTIVE

The aim of this qualitative study was to use a theory-based approach to understand the facilitators and barriers that impacted the implementation of the Primary Care Asthma Paediatric Pathway.

DESIGN

Qualitative semistructured focus groups following a randomised cluster-controlled design.

SETTING

22 primary care practices in Alberta, Canada.

PARTICIPANTS

37 healthcare providers participated in four focus groups to discuss the barriers and facilitators of pathway implementation.

INTERVENTION

An electronic medical record (EMR) based paediatric asthma pathway, online learning modules, in-person training for allied health teams in asthma education, and a clinical dashboard for patient management.

MAIN OUTCOME MEASURES

Our qualitative findings are organised into three themes using the core constructs of the normalisation process theory: (1) Facilitators of implementation, (2) Barriers to implementation, and (3) Proposed mitigation strategies.

RESULTS

Participants were positive about the pathway, and felt it served as a reminder of paediatric guideline-based asthma management, and an EMR-based targeted collection of tools and resources. Barriers included a low priority of paediatric asthma due to few children with asthma in their practices. The pathway was not integrated into clinic flow and there was not a specific process to ensure the pathway was used. Sites without project champions also struggled more with implementation. Despite these barriers, clinicians identified mitigation strategies to improve uptake including developing a reminder system within the EMR and creating a workflow that incorporated the pathway.

CONCLUSION

This study demonstrated the barriers and facilitators shaping the asthma pathway implementation. Our findings highlighted that if team support of enrolment (establishing buy-in), legitimisation (ensuring teams see their role in the pathway) and activation (an ongoing plan for sustainability) there may have been greater uptake of the pathway.

TRIAL REGISTRATION NUMBER

This study was registered at clinicaltrials.gov on 25 June 2015; the registration number is: NCT02481037, https://clinicaltrials.gov/ct2/show/NCT02481037?term=andrew+cave&cond=Asthma+in+Children&cntry=CA&city=Edmonton&draw=2&rank=1.

Rising Healthcare Costs and Utilization among Young Adults with Cirrhosis in Ontario: A Population-Based Study

OBJECTIVES

Chronic diseases account for the majority of healthcare spending. Cirrhosis is a chronic disease whose burden is rising, especially in young adults. This study aimed at describing the direct healthcare costs and utilization in young adults with cirrhosis compared to other chronic diseases common to this age group.

METHODS

Retrospective population-based study of routinely collected healthcare data from Ontario for the fiscal years 2007-2016 and housed at ICES. Young adults (aged 18-40 years) with cirrhosis, inflammatory bowel disease (IBD), and asthma were identified based on validated case definitions. Total and annual direct healthcare costs and utilization were calculated per individual across multiple healthcare settings and compared based on the type of chronic disease. For cirrhosis, the results were further stratified by etiology and decompensation status.

RESULTS

Total direct healthcare spending from 2007 to 2016 increased by 84% for cirrhosis, 50% for IBD, and 41% for asthma. On a per-patient basis, annual costs were the highest for cirrhosis ($6,581/year) compared to IBD ($5,260/year), and asthma ($2,934/year) driven by acute care in cirrhosis and asthma, and drug costs in IBD. Annual costs were four-fold higher in patients with decompensated versus compensated cirrhosis ($20,651/year vs. $5,280/year). Patients with cirrhosis had greater use of both ICU and mental health services.

CONCLUSION

Healthcare costs in young adults with cirrhosis are rising and driven by the use of acute care. Strategies to prevent the development of cirrhosis and to coordinate healthcare in this population through the development of chronic disease prevention and management strategies are urgently needed.

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.

Examining the role of pre-pregnancy weight and gestational weight gain in allergic disease development among offspring: A population-based cohort study in Ontario, Canada

BACKGROUND

Studies suggest maternal weight and weight gain during pregnancy may influence foetal immunological development. However, their role in the aetiology of allergic disease is unclear.

OBJECTIVES

We sought to examine the impact of maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) on the incidence of four common paediatric allergic diseases.

METHODS

We conducted a retrospective, population-based cohort study of all singleton live births in Ontario, Canada between 2012 and 2014, using maternal-newborn records from the provincial birth registry linked with health administrative databases. Neonates were followed up to 7 years for anaphylaxis, asthma, dermatitis and rhinitis, identified through validated algorithms based on healthcare encounters. We multiply imputed missing data and employed Cox proportional-hazards models to calculate adjusted hazard ratios (aHR) with 95% confidence intervals (CI). To test the robustness of our findings, we also conducted several sensitivity analyses, including probabilistic bias analyses for exposure and outcome misclassification. All methods were prespecified in a published protocol.

RESULTS

Of the 248,017 infants followed, 52% were born to mothers with a pre-pregnancy BMI in the normal range and only 19% were born to mothers with adequate weight gain during pregnancy. Incidence rates (per 100,000 person-days) for anaphylaxis, asthma, dermatitis and rhinitis were 0.22, 6.80, 12.41 and 1.54, respectively. Compared with normal BMI, maternal obesity was associated with increased hazards of asthma in offspring (aHR 1.08, 95% CI 1.05, 1.11), but decreased hazards of anaphylaxis (aHR 0.83, 95% CI 0.69, 0.99) and dermatitis (aHR 0.97, 95% CI 0.94, 0.99). In contrast, maternal underweight was associated with increased hazards of dermatitis (aHR 1.06, 95% CI 1.02, 1.10). We found no associations between pre-pregnancy BMI and rhinitis or GWG and any allergic outcome, and no evidence of effect measures modification by infant sex.

CONCLUSIONS

These findings provide support for the involvement of maternal pre-pregnancy BMI in paediatric allergic disease development.

Pediatric asthma incidence rates in the United States from 1980 to 2017

BACKGROUND

Few studies have examined longitudinal asthma incidence rates (IRs) from a public health surveillance perspective.

OBJECTIVE

Our aim was to calculate descriptive asthma IRs in children over time with consideration for demographics and parental asthma history.

METHODS

Data from 9 US birth cohorts were pooled into 1 population covering the period from 1980 to 2017. The outcome was earliest parental report of a doctor diagnosis of asthma. IRs per 1,000 person-years were calculated.

RESULTS

The racial/ethnic backgrounds of the 6,283 children studied were as follows: 55% European American (EA), 25.5% African American (AA), 9.5% Mexican-Hispanic American (MA) and 8.5% Caribbean-Hispanic American (CA). The average follow-up was 10.4 years (SD = 8.5 years; median = 8.4 years), totaling 65,291 person-years, with 1789 asthma diagnoses yielding a crude IR of 27.5 per 1,000 person-years (95% CI = 26.3-28.8). Age-specific rates were highest among children aged 0 to 4 years, notably from 1995 to 1999, with a decline in EA and MA children in 2000 to 2004 followed by a decline in AA and CA children in 2010 to 2014. Parental asthma history was associated with statistically significantly increased rates. IRs were similar and higher in AA and CA children versus lower but similar in EA and MA children. The differential rates by sex from birth through adolescence principally resulted from a decline in rates among males but relatively stable rates among females.

CONCLUSIONS

US childhood asthma IRs varied dramatically by age, sex, parental asthma history, race/ethnicity, and calendar year. Higher rates in the 0- to 4-year-olds group, particularly among AA/CA males with a parental history of asthma, as well as changes in rates over time and by demographic factors, suggest that asthma is driven by complex interactions between genetic susceptibility and variation in time-dependent environmental and social factors.

Childhood food insecurity and incident asthma: A population-based cohort study of children in Ontario, Canada

BACKGROUND

Childhood food insecurity has been associated with prevalent asthma in cross-sectional studies. Little is known about the relationship between food insecurity and incident asthma.

METHODS

We used administrative databases linked with the Canadian Community Health Survey, to conduct a retrospective cohort study of children <18 years in Ontario, Canada. Children without a previous diagnosis of asthma who had a household response to the Household Food Security Survey Module (HFSSM) were followed until March 31, 2018 for new asthma diagnoses using a validated administrative coding algorithm. We used multivariable Cox proportional hazard models to examine the association between food insecurity and incident asthma, and adjusted models sequentially for clinical and clinical/socioeconomic risk factors. As additional analyses, we examined associations by HFSSM respondent type, severity of food insecurity, and age of asthma diagnosis. Moreover, we assessed for interaction between food security and child's sex, household smoking status, and maternal asthma on the risk of incident asthma.

RESULTS

Among the 27,746 included children, 5.1% lived in food insecure households. Over a median of 8.34 years, the incidence of asthma was 7.33/1000 person-years (PY) among food insecure children and 5.91/1000 PY among food secure children (unadjusted hazard ratio [HR] 1.24, 95% CI 1.00 to 1.54, p = 0.051). In adjusted analyses associations were similar (HR 1.16, 95% CI 0.91 to 1.47, p = 0.24 adjusted for clinical risk factors, HR 1.24, 95% CI 0.97 to 1.60, p = 0.09 adjusted for clinical/socioeconomic factors). Associations did not qualitatively change by HFSSM respondent type, severity of food insecurity, and age of asthma diagnosis. There was no evidence of interaction in our models.

CONCLUSIONS

Food insecure children have numerous medical and social challenges. However, in this large population-based study, we did not observe that childhood food insecurity was associated with an increased risk of incident asthma when adjusted for important clinical and socioeconomic confounders.

Comparison of childhood asthma incidence in 3 neighbouring cities in southwestern Ontario: a 25-year longitudinal cohort study

BACKGROUND

Air pollution is a known trigger for exacerbations among individuals with asthma, but its role in the development of new-onset asthma is unclear. We compared the rate of new asthma cases in Sarnia, a city with high pollution levels, with the rates in 2 neighbouring regions in southwestern Ontario, Canada.

METHODS

Using a population-based birth cohort design and linked health administrative data, we compared the hazard of incident asthma among children 0 to 10 years of age between those born in Lambton (Sarnia) and those born in Windsor and London-Middlesex, for the period Apr. 1, 1993, to Mar. 31, 2009. We used Cox proportional hazards models to adjust for year of birth and exposure to air pollutants (nitrogen dioxide, sulphur dioxide [SO₂], ozone and small particulate matter [PM_2.5]), as well as maternal, geographic and socioeconomic factors.

RESULTS

Among 114 427 children, the highest incidence of asthma was in Lambton, followed by Windsor and London-Middlesex (30.3, 24.4 and 19.8 per 1000 person-years, respectively; p < 0.001). Relative to Lambton, the hazard of asthma, adjusted for socioeconomic and perinatal factors, was lower in Windsor (hazard ratio [HR] 0.72, 95% confidence interval [CI] 0.67-0.77) and London-Middlesex (HR 0.65, 95% CI 0.61-0.69). Inclusion of air pollutants attenuated this relative difference in both Windsor (HR 0.79, 95% CI 0.62-1.01) and London-Middlesex (HR 0.89, 95% CI 0.64-1.24).

INTERPRETATION

We identified a higher incidence of asthma among children born in Lambton (Sarnia) relative to 2 other regions in southwestern Ontario. Higher levels of air pollution (particularly SO₂ and PM_2.5) in this region, as experienced by children in their first year of life, may be contributory.

Hot spots for pediatric asthma emergency department visits in Ottawa, Canada

OBJECTIVE

Pediatric asthma emergency department (ED) visits and repeat visits place a substantial burden on healthcare. National and provincial level studies demonstrate geographic variation in asthma ED visits and links to marginalization, but preclude translation into practical targeting of healthcare delivery. It is important to understand the relationship between pediatric asthma ED visits and marginalization at a more granular level. To map the city-level geographic variation in pediatric asthma ED visit and re-visit rates at the Children's Hospital of Eastern Ontario (CHEO) in Ottawa, Canada and the relationship with marginalization.

METHODS

We performed a single center retrospective cohort study of children ages 1-17 with one or more ED visits for asthma at the CHEO in Ottawa. Using postal codes, we linked patients to census tracts. Per census tract, we mapped pediatric asthma ED visit and re-visit rates within one year and identified overlap with the Ontario Marginalization Index.

RESULTS

Of 1,620 children with an index ED visit, 18.5% had a repeat ED visit. We identified 10 hot spot census tracts each for pediatric asthma ED visit and re-visit rates. We identified an overlap between urban hot spots and areas with high ethnic concentration or low dependency.

CONCLUSION

At a granular, city-wide level, pediatric asthma ED visit and re-visit rates are heterogeneous. Urban hot spots, in contrast to rural, have more overlap with marginalization, especially ethnic concentration. These methods can be used in other jurisdictions to inform practical community strategies for geographically-targeted prevention of pediatric asthma-related ED visits in vulnerable areas.Abbreviations:ED:Emergency department;CHEO:Children's Hospital of Eastern Ontario;PRAM:Pediatric Respiratory Assessment Measure;ON-Marg:Ontario Marginalization Index;SES:Socioeconomic status;US:United States.

Supplemental data for this article can be accessed at publisher's website.

Developments in asthma incidence and prevalence in Alberta between 1995 and 2015

BACKGROUND

Asthma is a chronic respiratory disease characterized by reversible bronchoconstriction and airway inflammation. According to Statistics Canada in 2014, 8.1% of Canadians aged 12 and older reported having asthma diagnosed by a health care professional. Therefore, in 2014 there were an estimated 274,661 persons with asthma in Alberta. Most epidemiological studies estimate prevalence and incidence using survey-based data, which has limitations. The Ontario Asthma Surveillance Information System (OASIS) group has developed and validated an algorithm for epidemiologic asthma studies using provincial health databases. In Alberta, there are some studies using provincial databases, but most are restricted to emergency department visits and do not represent the entire asthma population. Using the validated asthma definition for epidemiologic studies, we performed an analysis of the Alberta Health administrative databases to investigate and report province-wide asthma prevalence, incidence and mortality in Alberta from 1995 to 2015.

METHODS

Data from administrative databases, provided by Alberta Health, was analyzed to determine age and sex specific prevalence, incidence and mortality of the asthma population. The population cohort was all individuals residing in the province of Alberta, ages 0 to 99 from 1995-2015. Kendall's Tau coefficient test was used to ascertain whether the observed trends were statistically significant.

RESULTS

Between 1995 and 2015, the age-standardized incidence of asthma decreased by more than 50% in both males and females. Prevalence, however, increased threefold over the 20 years (for both genders) from 3.9 to 12.3% (Tau = 1.00, p < 0.0001) in females and from 3.5 to 11.6% (Tau = 1.00, p < 0.0001) in males. Thus, in 2015 there were 496,927 people with asthma in Alberta. All-cause mortality in the asthma population decreased over time, in both females (Tau = - 0.71, p < 0.0001) and males (Tau = - 0.69, p = 0.0001). For the last several years, all-cause mortality was higher in those with asthma. There were ~ 7 deaths/1000 in the population with asthma versus ~ 5 deaths/1000 in those without asthma.

CONCLUSIONS

The incidence of asthma decreased in both females and males while prevalence continued to increase, although at a slower rate than previously. All-cause mortality in asthma patients was higher than in those without asthma, but both decreased over time.

Effectiveness and Safety of Inhaled Corticosteroids in Older Individuals with Chronic Obstructive Pulmonary Disease and/or Asthma. A Population Study

Rationale: Inhaled corticosteroids (ICS) are established medications for the management of both asthma and chronic obstructive pulmonary disease (COPD), two common chronic airway diseases. However, there is still uncertainty with respect to their use in some cases, specifically in older adults with asthma, people with concurrent asthma and COPD, and some people with COPD (given the association of ICS with pneumonia).Objectives: To compare the effectiveness and safety of ICS in older adults with asthma, COPD, or features of both in a real-word setting.Methods: In this retrospective longitudinal population cohort study, individuals 66 years of age or older in Ontario, Canada, who met a validated case definition of physician-diagnosed COPD and/or asthma between 2003 and 2014 were followed until March 2015 through provincial health administrative data. Overlap in COPD and asthma diagnoses was permitted and stratified for in subgroup analyses. The exposure was new receipt of ICS. The primary effectiveness and safety outcomes were hospitalizations for obstructive lung disease (OLD) and hospitalizations for pneumonia, respectively. Propensity scores were used to adjust for confounders.Results: The study included 87,690 individuals with asthma (27% with concurrent COPD) and 150,593 individuals with COPD (25% with concurrent asthma). In terms of effectiveness, controlling for confounders, ICS was associated with fewer hospitalizations for OLD (hazard ratio [HR], 0.84; 95% confidence interval [CI], 0.79-0.88) in subjects with asthma alone, with concurrent COPD attenuating the benefit. A similar association was seen in subjects with COPD and concurrent asthma (HR, 0.88; 95% CI, 0.84-0.92), but not in those with COPD alone, where ICS receipt had little impact on hospitalizations. In terms of safety, ICS receipt was associated with a marginally increased risk of pneumonia hospitalizations in people with COPD and no asthma (HR, 1.03; 95% CI, 1.00-1.06), but not in the other groups.Conclusions: ICS was associated with fewer hospitalizations for OLD in older adults with asthma and concurrent asthma and COPD, but had little impact on OLD and pneumonia hospitalizations in those with COPD alone.

Air pollution from industries and asthma onset in childhood: A population-based birth cohort study using dispersion modeling

BACKGROUND

Despite evidence that ambient air pollution may play a role in the development of asthma, little is known about the potential contribution of industrial emissions.

OBJECTIVE

We used a population-based birth cohort to investigate the association between asthma onset in childhood and residential exposure to industrial emissions, estimated from atmospheric dispersion modeling.

METHODS

The study population comprised all children born in the province of Quebec, Canada, 2002-2011. Asthma onset were ascertained from health administrative databases with validated algorithms. We used atmospheric dispersion modeling to develop time-varying annual mean concentration of ambient PM_2.5, NO₂ and SO₂ at participants' residence from industries. For each pollutant, we assessed the association between industrial emissions exposure and childhood asthma onset using Cox proportional hazard model, adjusted for sex, material and social deprivation and calendar year. Sensitivity analysis included adjusting for long-term regional and traffic-related ambient PM_2.5 and NO₂, and assessing potential confounding by unmeasured secondhand smoke.

RESULTS

The cohort included 722,667 children and 66,559 incident cases of asthma. For all pollutants, we found a non-linear association between childhood asthma onset and residential ambient air pollutant concentration from industries, with stronger effects at lower concentrations. A change from 25th to the 75th percentile in the mean annual ambient concentration of PM_2.5 (0.13 μg/m³), NO₂ (1.0 μg/m³) and SO₂ (1.6 μg/m³) from industrial emissions was associated with a 19% (95% CI: 17-20%), 21% (95% CI: 19-23%) and 23% (95% CI: 21-24%) increase in the risk of asthma onset in children, respectively. For PM_2.5 and NO₂, associations were persisting after adjustments for long-term regional PM_2.5 and traffic-related NO₂ ambient concentration.

CONCLUSION

Residential exposure to industrial emissions estimated from dispersion modeling was associated with asthma onset in childhood. Importantly, associations were stronger at lower concentrations and independent from those of other sources, thus adding up to the burden of regional and traffic-related air pollution.

Adult Asthma among Workers in Ontario. Results from the Occupational Disease Surveillance System

Rationale: Given that approximately 15% of new-onset adult asthma cases originate because of exposures in the workplace, there is a need for systematic and ongoing monitoring of risk among workers. Objectives: To characterize the risk of new-onset adult asthma among workers in Ontario. Methods: We used 575,379 provincial accepted time-loss workers' compensation claimants data linked to physician billing data. Workers aged 15 to 65 years with a nonasthma compensation claim between January 1, 2002, and December 31, 2013, were eligible for inclusion. Cohort entry corresponded to the date of the claim. The case definition required two or more records for asthma within a 12-month period, within a 3-year time window after cohort entry. A 3-year washout period preceding cohort entry was used to exclude prevalent cases. Workers at risk of new-onset adult asthma were followed from cohort entry date to date of diagnosis, emigration, age 65 years, death, or end of study period. Cox regression models were used to generate birth year- and sex-adjusted hazard ratios (HRs) by occupation, industry, and exposures identified using a job exposure matrix. Sex-stratified risk estimates were also generated. Results: Increased risks were detected among well-recognized groups, including bakers (HR, 1.60; 95% confidence interval [CI], 1.22-2.09) and painters and decorators (HR, 1.67; 95% CI, 1.23-2.28). In the job exposure matrix analysis, flour and isocyanates were associated with increased risk of asthma. Concrete finishers (HR, 1.93; 95% CI, 1.12-3.32) and shipping and receiving clerks (HR, 1.21; 95% CI, 1.03-1.43) also showed elevated risk, whereas results varied across woodworker groups. Decreased risks were detected for nursing and farming groups. Conclusions: This practical data linkage approach was successful for examining associations across hundreds of jobs. Unexpected and previously unrecognized findings deserve further investigation and emphasize the importance of an ongoing system to guide research as well as prevention.

Generational Patterns of Asthma Incidence among Immigrants to Canada over Two Decades. A Population-based Cohort Study

RATIONALE

Canada, an industrialized country with high endemic asthma rates, is characterized by a large immigrant population.

OBJECTIVES

We sought to provide insight into the relative contribution of environmental exposure to asthma risk by comparing asthma rates among recent immigrants relative to long-term residents of Canada.

METHODS

This was a population-based, retrospective cohort study performed using provincial health administrative data for all residents of Ontario, Canada. Residents with and without a diagnosis of asthma from fiscal years 1996-2012 were included. Individuals were categorized as being immigrants (landed in Canada after 1985) or long-term residents of Ontario by linkage with the Immigration, Refugees, and Citizenship Canada's Permanent Resident Database. We calculated the age- and sex-standardized incidence of asthma among residents of Ontario, and compared the incidence of asthma among immigrants and long-term residents using incidence rate ratios (IRRs).

RESULTS

Analysis of approximately 11.7 million records showed that 2.2 immigrants arrived in Canada during the study period, with over 50% from East and South Asia and the Pacific. We found that asthma incidence was lower among immigrants compared with long-term residents (IRR = 0.30; 95% confidence interval = 0.30-0.30; P < 0.001). However, Ontario-born children of immigrants from most world regions had significantly higher asthma incidence compared with children of long-term residents (IRR = 1.44; 95% confidence interval = 1.43-1.45; P < 0.001). The overall incidence of asthma in Ontario decreased between 1996 and 2012 (P_trend < 0.001). Immigrants contributed to only a small proportion of the asthma incidence in Ontario, and changes within this group did not significantly affect trends in the overall Ontario population asthma incidence.

CONCLUSIONS

The higher asthma incidence seen among children of immigrants, but not in their parents, suggests that being born in Canada was critical for determining asthma risk. These findings support the importance of in utero and/or early life exposures on asthma development.

What have we learnt about asthma control from trials of budesonide/formoterol as maintenance and reliever?

Despite improvements in medications, devices and understanding of the disease, about half of all asthma patients worldwide remain inadequately controlled, suggesting the need for a new approach to asthma management. Poor adherence to prescribed maintenance therapy and over-reliance on SABA reliever medication is a common cause of inadequate control. This article reviews published data from 6- to 12-month, double-blind, RCT and open-label real-world studies involving budesonide/formoterol maintenance and reliever therapy (MART) and relevant comparator approaches to asthma management, and considers how these compare in achieving the treatment goals described in guidelines. The data confirm that patients with asthma treated with budesonide/formoterol MART achieved the same or better asthma symptom control compared with ICS/LABA plus SABA regimens at similar or higher ICS doses, with consistently lower rates of exacerbations and considerably lower annual requirement for oral corticosteroids. These findings have been confirmed across a range of severities of persistent asthma. With the MART approach, maintenance dosing ensures coverage for day-to-day control, and the use of a reliever with anti-inflammatory properties (budesonide/formoterol) provides extra doses of ICS as soon as symptoms prompt the use of reliever, resulting in a 40-50% reduction of exacerbations compared with an ICS-based treatment approach plus as-needed SABA as reliever. As-needed, budesonide/formoterol has also recently been shown to be more effective as a reliever in mild asthma than SABA alone, reducing exacerbations by up to 64% in the SYGMA studies.

Trends and regional distribution of outpatient claims for asthma, 2009-2016, Germany

OBJECTIVE

To investigate asthma morbidity in Germany by calculating current prevalence, examining its temporal and spatial trends and estimating the total number of asthmatics in Germany and calculating age-, sex- and residence-specific risk.

METHODS

We used claims data reported by physicians during 2009-2016, including outpatient diagnoses of all statutory health insured individuals, comprising 85.3% (70 416 019/82 521 653) of the total population in Germany in 2016. We performed a spatial analysis of asthma prevalence according to administrative district by calculating Global and Local Moran's I. We assessed the risk of asthma by sex, age, type of residence (rural versus urban) and federal state (East versus West) using a multilevel parametric survival regression.

FINDINGS

We estimated that 4.7 million individuals were affected by asthma in 2016, including 0.8 million children and 3.9 million adults. We observed a slightly higher prevalence (with an increasing trend) among adults (5.85%; 3 408 622/58 246 299) compared to children (5.13%; 624 899/12 169 720), and calculated an age-standardized prevalence of 5.76% (95% confidence interval, CI: 5.76-5.77). We found evidence of a strong spatial autocorrelation (Global Moran's I: 0.50, P < 0.0001), and identified local spatial clusters with higher levels of prevalence. Living in the western (versus eastern) federal states and living in densely populated large urban municipalities (versus rural area) were independently associated with an increased risk of asthma, with hazard ratios of 1.33 (95% CI: 1.32-1.34) and 1.32 (95% CI: 1.31-1.32), respectively.

CONCLUSION

Our insights into the spatial distribution of asthma morbidity may inform public health interventions, including region-specific prevention programmes and control.

Factors associated with emergency department presentation after total joint arthroplasty: a population-based retrospective cohort study

BACKGROUND

Unplanned visits to the emergency department after total joint arthroplasty are far more common than unplanned readmissions. Our objectives were to characterize the prevalence of presentation to an emergency department for any reason after total joint arthroplasty and to identify risk factors for such visits.

METHODS

Using health administrative databases, we conducted a population-based retrospective cohort study of adults (19-89 yr of age) who received their first primary elective total hip arthroplasty (THA) or total knee arthroplasty (TKA) procedure for arthritis between April 2011 and March 2016 in Ontario. We made univariate comparisons between patients who presented to the emergency department within 30 days of surgery and those who did not in. We determined differences in use of health care services between groups by comparing the change in use in the year before and after surgery between patients who presented to the emergency department and those who did not. We developed logistic regression models for the occurrence of an emergency department visit using backward variable elimination.

RESULTS

We identified 42 273 total hip recipients and 70 725 total knee recipients, of whom 5640 (13.3%) and 11 224 (15.9%), respectively, presented to the emergency department within 30 days of surgery. Fewer than 1% of these patients required admission, and nearly half (45%) went to a different institution from where they had their surgery. Among both THA and TKA recipients, patients who presented to the emergency department had a net increase in their median annual health care costs (THA: $501, TKA: $682), compared to a net decrease for the cohort as a whole. Factors associated with increased risk of an emergency visit included increased patient age, male sex, rural residence and various comorbidities. Predictive regression models showed poor discriminative ability for both THA (C-statistic 0.57) and TKA (C-statistic 0.58) recipients.

INTERPRETATION

One in 7 patients presented to the emergency department within 30 days of THA or TKA. Some may conceivably have been managed remotely, and very few required readmission. There is a crucial need for strategies to minimize these events.

Sex differences in the association between asthma incidence and modifiable risk factors in Korean middle-aged and older adults: NHIS-HEALS 10-year cohort

Background

This study investigated the sex-specific incidence of asthma and the effects of modifiable risk factors, particularly obesity, on asthma incidence among middle-aged and older individuals in Korea.

Methods

We used data from the National Health Insurance Service-Health Screening Cohort (NHIS-HEALS), which includes health examinees aged 40–79 years in 2002–2003. In total, 459,529 participants with baseline anthropometric measurements were followed-up for 10 years and the development of asthma was evaluated (2004–2013). For subgroup analysis, 246,019 participants who had body mass index (BMI) and waist circumference (WC) measurements taken in 2008–2009 were included in the analysis of the asthma incidence for 2010–2013. Factors associated with asthma were analysed using Cox proportional hazard models.

Results

The cohort comprised 4,248,813 (men, 2,358,541; women, 1,890,272) person-years of follow-up for 2004–2013. The asthma incidence was 10.58 and 15.03 per 1000 person-years for men and women, respectively. Asthma incidence increased with age, notably so in men. Obesity based on the baseline BMI was significantly associated with asthma development in both sexes (men, HR = 1.23, 95% confidence interval (CI) = 1.13–1.34; women, HR = 1.40 95% CI = 1.32–1.48). High WC was also related to asthma incidence in both sexes with statistical significance (men, HR = 1.34, 95% CI = 1.16–1.57; women, HR = 1.19 95% CI = 1.03–1.37). Analysis of the combined effects of BMI and WC showed that men had a higher asthma risk in the group with both general obesity and abdominal obesity than in the group with non-abdominal obesity and normal BMI. However, obese women had a higher risk of asthma regardless of abdominal obesity. Similarly, smoking was associated with asthma in both sexes but drinking and physical activity showed different associations between the sexes.

Conclusions

Our results revealed that asthma incidence was substantially high at old age and lifestyle factors were associated with asthma development. Practical strategies including weight control and healthy lifestyle modification are required to prevent asthma in older people.

Sex differences in health services and medication use among older adults with asthma

Sex differences are well documented in chronic disease populations with cardiovascular disease and diabetes. Although recent research has suggested that asthma is more severe in older women compared to men, the extent of this difference remains poorly understood. The objective of this study was to compare rates of asthma-specific health services use (HSU) and medication use, between older women and men with asthma.

This population-based cohort study included 209 054 individuals aged ≥66 years with asthma from health administrative data in Ontario, Canada. The primary exposure was sex. Outcomes included asthma-specific HSU (spirometry, emergency department (ED), hospitalisation, physician office and specialist visits) and medication use (asthma controller and reliever prescriptions). Negative binomial regression models adjusted for age, socioeconomic status and comorbidities were used to ascertain outcomes by sex from 2010 to 2016.

Compared to men, women had lower rates of spirometry (adjusted relative rate (ARR) 0.87, 95% CI 0.85–0.89) and specialist visits for asthma (ARR 0.93, 95% CI 0.90–0.96), but higher rates of asthma-specific ED (ARR 1.43, 95% CI 1.33–1.53) and physician office visits (ARR 1.03, 95% CI 1.01–1.05). Women also had lower asthma controller (ARR 0.98, 95% CI 0.97–0.99) but higher asthma reliever (ARR 1.03, 95% CI 1.02–1.05) prescription fill rates, compared to men.

These findings may indicate poorer disease control, greater asthma severity and poorer access to specialist asthma care in women.

Older women with asthma have lower rates of spirometry, asthma specialist visits and asthma controller fill rates, and higher rates of ED visits for asthma, physician office visits for asthma and asthma reliever fill rates, compared to menhttp://bit.ly/33PfMD6

Age, period, and cohort effects on asthma prevalence in Canadian adults, 1994-2011

PURPOSE

To examine the age, period, and cohort effects on asthma prevalence among Canadian adults from 1994/1995 to 2010/2011.

METHODS

Using data from the National Population Health Survey, 13,616 Canadian adults were followed for 16 years. Age was limited to 18-80 years during follow-up. Modified Poisson regression models with generalized estimating equations were used to estimate age, period, and cohort effects on asthma and active asthma prevalence after accounting for sociodemographic factors. Model-based standardization was performed to estimate standardized rates.

RESULTS

Overall asthma prevalence increased from 5% in 1994/1995 to 11% in 2010/2011; decreasing from 12% for 20-year-olds to 6% for 50-60-year-olds and then increased to 8% for 80-year-olds. Individuals aged 20 years had the steepest increase in prevalence between 1994/1995 and 2010/2011. Active asthma prevalence increased from 5% in 1994/1995 to 8% in 2010/2011; decreasing from 8% for 20-year-olds to 5% for 50-60-year-olds and then increased to 6% for 80-year-olds.

CONCLUSIONS

Our findings suggest the presence of age, period, and cohort effects on prevalence of asthma overall and presence of age and period effects on active asthma prevalence in Canadian adults.

Agreement between a health claims algorithm and parent-reported asthma in young children

INTRODUCTION

Asthma prevalence is commonly measured in national surveys by questionnaire. The Ontario Asthma Surveillance Information System (OASIS) developed a validated health claims diagnosis algorithm to estimate asthma prevalence. The primary objective was to assess the agreement between two approaches of measuring asthma in young children. Secondary objectives were to identify concordant and discordant pairs, and to identify factors associated with disagreement.

STUDY DESIGN AND SETTING

A measurement study to evaluate the agreement between the OASIS algorithm and parent-reported asthma (criterion standard). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. Multivariable logistic regression was used to determine factors associated with disagreement.

RESULTS

Healthy children aged 1 to 5 years (n =3642) participating in the TARGet Kids! practice based research network 2008-2013 in Toronto, Canada were included. Prevalence of asthma was 14% and 6% by the OASIS algorithm and parent-reported asthma, respectively. The Kappa statistic was 0.43, sensitivity 81%, specificity 90%, PPV 34%, and NPV 99%. There were 3249 concordant and 393 discordant pairs. Statistically significant factors associated with asthma identified by OASIS but not parent report included: male sex, higher zBMI, and parent history of asthma. Males were less likely to have asthma identified by parent report but not OASIS.

CONCLUSION

The OASIS algorithm identified more asthma cases in young children than parent-reported asthma. The OASIS algorithm had high sensitivity, specificity, and NPV but low PPV relative to parent-reported asthma. These findings need replication in other populations.

Understanding an Environmental Health Risk: Investigating Asthma Risk Perception in Ontario Youth Sport

The environment, broadly defined, plays a significant role in shaping human health. Understanding how environmental health risks are perceived by different people, in different places, and at different times is critical to their management. Using a place-based conceptual framework, this research investigates asthma risk perception determinants and outcomes amongst organized team sport stakeholders in Ontario. Two online surveys (coaches, n = 94; parents of athletes diagnosed with allergic disease, n = 90) were conducted. Binary regression was used to investigate determinants of risk perception. Asthma ranked seventh of 17 health hazards by coaches (23% ranked as high) and parents (34%), and determinants of risk included trigger knowledge, risk exposure, propensity for risk, indicators of trust, and socioeconomic variables (e.g., gender). As policy-makers look to manage health risks in sport, considering the risk profiles of different stakeholders (e.g., coaches, parents of vulnerable athletes), as well as the characteristics of the places in which risk is experienced, is critical to improving environment and health management in organized youth team sports.

Prevalence of asthma and allergic symptoms in Suzhou, China: Trends by domestic migrant status

Rapid urbanization in developing countries, with significant rural-to-urban and between-urban areas migration, presents a natural epidemiological model to better understand population-level trends in asthma and allergy prevalance without confounding by genetic factors. This cross-sectional study, conducted November 2014 to January 2015 in Suzhou, China, investigated differences in asthma and allergic symptoms between domestic migrant residents and long-term residents and their children. Using multivariate logistic regression, the odds ratios for children in migrant families compared to those in long-term resident families in Suzhou for doctor-diagnosed asthma, pneumonia, rhinitis, and eczema were 0.56 (95% CI: 0.42.0.73), 0.60 (95% CI: 0.49, 0.72), 0.63 (95% CI:0.52, 0.77), and 0.73 (95% CI: 0.60, 0.89), respectively. While there was a lower prevalence of asthma and allergic symptoms for domestic migrants (children and parents) compared to the local population in Suzhou, migrant children had a higher asthma rate than their parents. This follows the trend of increasing asthma rates for children in the urban local population, suggesting an environmental component. Parental migration plays a role in both parental and children's health but further investigations are needed to determine how these results may be shaped by early life exposures, lifestyle differences, and other environmental factors.

Trends in chronic disease incidence rates from the Canadian Chronic Disease Surveillance System

INTRODUCTION

The Public Health Agency of Canada's Canadian Chronic Disease Surveillance System (CCDSS) produces population-based estimates of chronic disease prevalence and incidence using administrative health data. Our aim was to assess trends in incidence rates over time, trends are essential to understand changes in population risk and to inform policy development.

METHODS

Incident cases of diagnosed asthma, chronic obstructive pulmonary disease (COPD), diabetes, hypertension, ischemic heart disease (IHD), and stroke were obtained from the CCDSS online infobase for 1999 to 2012. Trends in national and regional incidence estimates were tested using a negative binomial regression model with year as a linear predictor. Subsequently, models with year as a restricted cubic spline were used to test for departures from linearity using the likelihood ratio test. Age and sex were covariates in all models.

RESULTS

Based on the models with year as a linear predictor, national incidence rates were estimated to have decreased over time for all diseases, except diabetes; regional incidence rates for most diseases and regions were also estimated to have decreased. However, likelihood ratio tests revealed statistically significant departures from a linear year effect for many diseases and regions, particularly for hypertension.

CONCLUSION

Chronic disease incidence estimates based on CCDSS data are decreasing over time, but not at a constant rate. Further investigations are needed to assess if this decrease is associated with changes in health status, data quality, or physician practices. As well, population characteristics that may influence changing incidence trends also require exploration.

Evaluation of eczema, asthma, allergic rhinitis and allergies among the grade-7 children of Iqaluit

Background

Little is known about the prevalence of asthma, allergic rhinitis, eczema and allergies among Canadian Inuit children, especially those living in the arctic and subarctic areas.

Methods

A cross-sectional study among grade seven students attending schools in Iqaluit, the capital city of Nunavut, was conducted during the 2016/2017 school year. We used the International Study of Allergy and Asthma in Children (ISAAC) questionnaire with added questions relevant to the population. In addition, skin prick tests (SPT) were conducted to test for sensitization to common food and environmental allergens.

Results

The prevalence of current asthma is 5.2%, all of them were males and 2/3 of them were Inuit and all had a previous respiratory hospitalization. Past asthma prevalence is 8.6%, 60% males and 60% Inuit. There was an inverse relationship to crowdedness possibly as a confounding factor because of getting a higher prevalence among the non-Inuit who usually live in less crowded houses. Current allergic rhinitis prevalence is 8.6%, 60% of the cases were among the mixed Inuit/Caucasian ethnicity while no cases among the non-Inuit, there was a female predominance 3:2. Past history of allergic rhinitis prevalence is 10.3%, half of the cases were among the mixed ethnicity (5.2% of that ethnicity) followed by Inuit (3.4%) and non-Inuit (1.7%), female: Male ratio 1:1. Current eczema prevalence was 27.6%, with half of the cases among the mixed ethnicity (13.8% of that group), followed by Inuit (8.6%). There was a female predominance with protective effect of exclusive breastfeeding. Past eczema prevalence 34.5%, with half of the cases were among the mixed ethnicity (17.2% of that group), followed by Inuit (10.3%). There was a female predominance. We noted a high rate of sensitization to Cat at 29.2%, most of the cases were among the mixed ethnicity, while absent sensitization to other common inhalant allergens.

Conclusion

While being cautious about firm conclusions due to the small sample size and power, the noticed variations in the prevalence and risk factors of asthma, allergic rhinitis and eczema among different ethnicities living at the same subarctic environment might be related to several possible explanations like genetic, gene-environment interaction and/or lifestyle factors, it was out of the scope of this study to determine the causality of such variation in prevalence, which emphasizes the need for further investigation.

Trend of self-reported asthma prevalence in Brazil from 2003 to 2013 in adults and factors associated with prevalence

Objectives:

To determine the trend of self-reported asthma diagnosed prevalence and to describe the factors associated with asthma in Brazilian adults.

Method:

Epidemiological cross-sectional study based on databases analysis from three national household surveys: Pesquisa Nacional por Amostra de Domicílios (PNAD) 2003, PNAD 2008 and Pesquisa Nacional de Saúde (PNS) 2013. Participants between 18-45 years old were included. Trend analysis of asthma diagnosed prevalence was conducted using a logistic general linear model. A hierarchical logistic regression model was used to select factors significantly associated with asthma prevalence.

Results:

Asthma diagnosed prevalence was 3.6% (2003), 3.7% (2008) and 4.5% (2013), showing a statistically significant increased trend. Asthma diagnosed prevalence also increased when analysed by gender (annual change for men: 2.47%, p < 0.003; women: 2.16%, p < 0.001), urban area (annual change for urban: 2.15%, p < 0.001; rural: 2.69%, p = 0.072), healthcare insurance status (annual change without healthcare insurance: 2.18%, p < 0.001; with healthcare insurance: 1.84%, p = 0.014), and geographic regions (annual change North: 4.68%, p < 0.001; Northeast: 4.14%, p < 0.001; and Southeast: 1.84%, p = 0.025). Female gender, obesity, living in urban areas and depression were associated with asthma diagnosed prevalence.

Discussion:

PNAD and PNS surveys allow for a very large, representative community-based sample of the Brazilian adults to investigate the asthma prevalence. From 2003 to 2013, the prevalence of self-reported physician diagnosis of asthma increased, especially in the North and Northeast regions. Gender, region of residence, household location (urban/rural), obesity, and depression diagnosis seem to play significant roles in the epidemiology of asthma in Brazil.

Modified Si-Jun-Zi-Tang Attenuates Airway Inflammation in a Murine Model of Chronic Asthma by Inhibiting Teff Cells via the mTORC1 Pathway

Background: Modified Si–Jun–Zi–Tang (MSJZT), a multi-herb formulation, is frequently used in traditional Chinese medicine for patients during the remission stage of asthma. However, the pharmacological basis underlying the effects of MSJZT on asthma has yet to be elucidated. This study aims at evaluating the anti-asthmatic effects of MSJZT and investigating its possible mechanism.

Methods: A chronic murine model of asthma was established by sensitization and repeated challenge with ovalbumin (OVA) in female BALB/c mice, followed with oral administration of MSJZT during remission, and then mouse were re-challenged by OVA. The chemical profile of MSJZT was analyzed by high-performance liquid chromatography. The characteristic features of allergic asthma, including airway hyperreactivity, histopathology, cytokine levels (IL-4, -5, -13, -17, and INF-γ), T regulatory (Treg) lymphocytes (Foxp3+CD4+CD25+), and T effector (Teff) lymphocytes (Foxp3-CD25+CD4+) in bronchoalveolar lavage fluid (BALF), and downstream proteins of mTORC1/2 signaling pathway were examined.

Results: MSJZT markedly suppressed airway hyper-responsiveness to aerosolized methacholine, and reduced levels of IL-4, IL-5, and IL-13 in the BALF. Histological studies showed that MSJZT significantly reduced inflammatory infiltration in lung tissues. The percentage and absolute number of Teff cells were suppressed to a remarkable level by MSJZT without affecting Treg cells. Furthermore, MSJZT effectively inhibited the mTORC1 activity, but exerted limited effects on mTORC2, as assessed by the phosphorylation of the mTORC1 and mTORC2 substrates, S6 ribosomal protein, p70 S6 kinase, mTOR S2481, and Akt, respectively.

Conclusion: MSJZT attenuated chronic airway inflammation in a mouse model of asthma by inhibiting Teff cells, which occurred, at least in part, via modulation of the mTORC1 signaling pathway.

Impact of two oral doses of 100,000 IU of vitamin D3 in preschoolers with viral-induced asthma: a pilot randomised controlled trial

Background

New evidence supports the use of supplemental vitamin D in the prevention of exacerbation of asthma; however, the optimal posology to sufficiently raise serum levels while maximising adherence is unclear. The objective was to ascertain the efficacy of high-dose vitamin D₃ in increasing serum vitamin D in preschoolers with asthma and provide preliminary data on safety and efficacy outcomes.

Methods

We conducted a 7-month, triple-blind, randomised, placebo-controlled, pilot trial of children aged 1–5 years with viral-induced asthma. Participants were allocated to receive two oral doses of 100,000 IU vitamin D₃ (intervention) or identical placebo (control) 3.5 months apart, once in the fall and once in the winter. Serum 25-hydroxyvitamin D (25OHD) was measured by tandem mass spectrometry at baseline, 10 days, 3.5 months, 3.5 months + 10 days, and 7 months. The main outcome was the change in serum 25OHD from baseline (Δ25OHD) over time and at 3.5 and 7 months; other outcomes included the proportion of children with 25OHD ≥ 75 nmol/L, safety, and adverse event rates.

Results

Children (N = 47) were randomised (intervention, 23; control, 24) in the fall. There was a significant adjusted group difference in the Δ25OHD (95% confidence interval) of 57.8 (47.3, 68.4) nmol/L, p < 0.0001), with a time (p < 0.0001) and group*time interaction effect (p < 0.0001), in favour of the intervention. A significant group difference in the Δ25OHD was observed 10 days after the first (119.3 [105.8, 132.9] nmol/L) and second (100.1 [85.7, 114.6] nmol/L) bolus; it did not reach statistical significance at 3.5 and 7 months. At 3.5 and 7 months, respectively, 63% and 56% of the intervention group were vitamin D sufficient (≥ 75 nmol/L) compared to 39% and 36% of the control group. Hypercalciuria, all without hypercalcaemia, was observed in 8.7% of intervention and 10.3% of control samples at any time point. Exacerbations requiring rescue oral corticosteroids, which appear as a promising primary outcome, occurred at a rate of 0.87/child.

Conclusion

Two oral boluses of 100,000 IU vitamin D_3,once in the fall and once in the winter, rapidly, safely, and significantly raises overall serum vitamin D metabolites. However, it is sufficient to maintain 25OHD ≥ 75 nmol/L throughout 7 months in only slightly more than half of participants.

Trial registration

ClinicalTrials.gov, NCT02197702 (23 072014). Registered on 23 July 2014.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3184-z) contains supplementary material, which is available to authorized users.

A population-based birth cohort study of the association between childhood-onset asthma and exposure to industrial air pollutant emissions

BACKGROUND

Studies of the association between air pollution and asthma onset have mostly focused on urban and traffic-related air pollution. We investigated the associations between exposure to industrial emissions and childhood-onset asthma in a population-based birth cohort in Quebec, Canada, 2002-2011.

METHODS

The cohort was built from administrative health databases. We developed separately for PM_2.5 and SO₂ different metrics representing children's time-varying residential exposure to industrial emissions: 1) yearly number of tons of air pollutant emitted by industries located within 2.5 km of the residence; 2) distance to the nearest "major emitter" (≥100 tons) of either PM_2.5 and SO₂ within 7.5 km of the residence, and; 3) tons of air pollutant emitted by the nearest "major emitter" within 7.5 km, weighted by the inverse of the distance and the percentage of time that the residence was downwind. To handle the large number of zeros (i.e., children unexposed) we decomposed the exposure variable into two covariates simultaneously included in the regression model: a binary indicator of exposure and a continuous exposure variable centered at the mean value among exposed children. We performed Cox models using age as the time axis, adjusted for gender, material and social deprivation and calendar year. We indirectly adjusted for unmeasured secondhand smoke.

RESULTS

The cohort included 722,667 children and 66,559 incident cases of asthma. Across the different exposure metrics, mean percentage changes in the risk of asthma onset in children exposed to the mean relative to those unexposed ranged from 4.5% (95% CI: 2.8, 6.3%) to 10.6% (95% CI: 6.2, 15.2%) for PM_2.5 and, from 1.1% (95% CI: -0.1, 3.3%) to 8.9% (95% CI: 7.1, 11.1%) for SO₂. Indirect adjustment for secondhand smoke did not substantially affect the associations. In children exposed, the risk of asthma onset increased with the magnitude of the exposure for all metrics, except the distance to the nearest major emitter of SO₂.

CONCLUSIONS

In this population-based birth cohort, residential exposure to industrial air pollutant emissions was associated with childhood-onset asthma. Additional studies with improved models for estimating exposure to industrial point-sources are needed to further support the observed associations.

A survey of ambulatory-treated asthma and correlation with weather and air pollution conditions within Taiwan during 2001-2010

Objective: This study of asthma was performed to evaluate annual trends in emergency department (ED) for 10 years. Weather and air pollution factors affecting asthma were also studied in order to identify the important factors and alert the public in advance. Methods: A survey of ambulatory-treated asthma patients was performed and the correlations with weather and air pollution factors examined in a cohort of one million patients in 2010. The fixed-cohort study analyzed trends, medical costs, and annual prevalence grouped by age and gender. Results: The number of asthma patients visiting EDs and non-emergency (non-ED) clinics significantly increased, with average annual percentage changes (AAPCs) of 2.3 and 4.6%, respectively. The average direct medical cost for EDs was increased significantly as compared with that of non-ED visits. Classification of asthma visits by hospital level indicated that local hospitals and others exhibited a significantly increasing trend (AAPC =15.3% [95% CI: 14.3-16.2]). The annual prevalence of asthma in males, females, and children was significantly increased (AAPCs of 1.5, 1.8, and 3.9%, respectively). Asthma patient hospitalizations were significantly correlated with temperature, humidity, and air pollution factors. Conclusions: The number of non-ED visits due to asthma increased, and the average direct medical cost for ED admissions also increased. Asthma patients tended to visit local hospitals primarily. Asthma visits by children increased, but a decrease was observed in adults. The number of hospitalized asthma patients was negatively correlated with temperature and humidity but positively correlated with the levels of PM_2.5, PM₁₀, and NO₂.

Changing patterns of adult asthma incidence: results from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database in Korea

This study was conducted to assess the changes in the annual incidence of adult asthma in Korea where the prevalence of asthma had increased steadily in recent decades. A population-based cohort study was conducted using the National Health Insurance Service–National Sample Cohort (NHIS-NSC), which consisted of 746,816 adults aged >20 years between 2004 and 2012. Asthma was defined by two or more physician claims on the basis of a primary diagnostic code for asthma and administration of asthma medications within 1 year. The incidence rates and annual percent change were calculated, and the influence of age and sex on the incidence rates was studied. The annual asthma incidence increased from 3.63 in 2004 to 6.07 per 1,000 person-years in 2008. Since 2008, the asthma incidence did not change significantly. The asthma incidence was higher in women than in men throughout the study periods (p < 0.001) and higher in older than younger age groups (p < 0.001). The asthma incidence did not change in all ages since 2008, except for the 20 s who showed a steady increase. The incidence of asthma in adults reached plateau in Korea, which is consistent with the results from studies in other countries.

Asthma

Asthma is the most common respiratory disorder in Canada. Despite significant improvement in the diagnosis and management of this disorder, the majority of Canadians with asthma remain poorly controlled. In most patients, however, control can be achieved through the use of avoidance measures and appropriate pharmacological interventions. Inhaled corticosteroids (ICS) represent the standard of care for the majority of patients. Combination ICS/long-acting beta₂-agonist inhalers are preferred for most adults who fail to achieve control with ICS therapy. Biologic therapies targeting immunoglobulin E or interleukin-5 are recent additions to the asthma treatment armamentarium and may be useful in select cases of difficult to control asthma. Allergen-specific immunotherapy represents a potentially disease-modifying therapy for many patients with asthma, but should only be prescribed by physicians with appropriate training in allergy. In addition to avoidance measures and pharmacotherapy, essential components of asthma management include: regular monitoring of asthma control using objective testing measures such as spirometry, whenever feasible; creation of written asthma action plans; assessing barriers to treatment and adherence to therapy; and reviewing inhaler device technique. This article provides a review of current literature and guidelines for the appropriate diagnosis and management of asthma in adults and children.

Profiling of healthy and asthmatic airway smooth muscle cells following interleukin-1β treatment: a novel role for CCL20 in chronic mucus hypersecretion

Chronic mucus hypersecretion (CMH) contributes to the morbidity and mortality of asthma, and remains uncontrolled by current therapies in the subset of patients with severe, steroid-resistant disease. Altered cross-talk between airway epithelium and airway smooth muscle cells (ASMCs), driven by pro-inflammatory cytokines such as interleukin (IL)-1β, provides a potential mechanism that influences CMH. This study investigated mechanisms underlying CMH by comparing IL-1β-induced gene expression profiles between asthma and control-derived ASMCs and the subsequent paracrine influence on airway epithelial mucus production in vitroIL-1β-treated ASMCs from asthmatic patients and healthy donors were profiled using microarray analysis and ELISA. Air-liquid interface (ALI)-cultured CALU-3 and primary airway epithelial cells were treated with identified candidates and mucus production assessed.The IL-1β-induced CCL20 expression and protein release was increased in ASMCs from moderate compared with mild asthmatic patients and healthy controls. IL-1β induced lower MIR146A expression in asthma-derived ASMCs compared with controls. Decreased MIR146A expression was validated in vivo in bronchial biopsies from 16 asthmatic patients versus 39 healthy donors. miR-146a-5p overexpression abrogated CCL20 release in ASMCs. CCL20 treatment of ALI-cultured CALU-3 and primary airway epithelial cells induced mucus production, while CCL20 levels in sputum were associated with increased levels of CMH in asthmatic patients.Elevated CCL20 production by ASMCs, possibly resulting from dysregulated expression of the anti-inflammatory miR-146a-5p, may contribute to enhanced mucus production in asthma.