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

Aeroallergens in Canada: Distribution, Public Health Impacts, and Opportunities for Prevention

Aeroallergens occur naturally in the environment and are widely dispersed across Canada, yet their public health implications are not well-understood. This review intends to provide a scientific and public health-oriented perspective on aeroallergens in Canada: their distribution, health impacts, and new developments including the effects of climate change and the potential role of aeroallergens in the development of allergies and asthma. The review also describes anthropogenic effects on plant distribution and diversity, and how aeroallergens interact with other environmental elements, such as air pollution and weather events. Increased understanding of the relationships between aeroallergens and health will enhance our ability to provide accurate information, improve preventive measures and provide timely treatments for affected populations.

30-year trends in asthma and the trends in relation to hospitalization and mortality

INTRODUCTION

The present study examines how trends in the prevalence of asthma during the past three decades associate with hospitalization and mortality during the same period.

METHODS

Altogether 54 320 subjects aged 25-74 years were examined in seven independent cross-sectional population surveys repeated every five years between 1982 and 2012 in Finland. The study protocol included a standardized questionnaire on self-reported asthma, smoking habits and other risk factors, and clinical measurements at the study site. Data on hospitalizations were obtained from the Care Register for Health Care, and data on mortality from the National Causes of Death register.

RESULTS

During the study, the prevalence of asthma increased - especially in women. In asthmatic compared with non-asthmatic subjects, hospitalization was significantly higher for all causes, respiratory causes, cardiovascular causes and lung cancer. In addition, particularly in asthmatic subjects, mean yearly hospital days in the 5-year periods after each survey diminished. In asthmatic subjects, the decrease in yearly all-cause hospital days was from 4.45 (between 1982 and 1987) to 1.11 (between 2012 and 2015) and in subjects without asthma the corresponding decrease was from 1.77 to 0.60 (p < 0.001). Similarly between 1982 and 2015, COPD hospitalization decreased more in asthmatic than in non-asthmatic subjects. Generally in the present study, all-cause mortality decreased between 1982 and 2015, though mortality in asthmatic subjects compared with non-asthmatics was higher from all causes, respiratory causes and lung cancer.

CONCLUSION

There was an increasing trend in the prevalence of asthma and a declining trend in hospitalization, especially in asthmatic subjects.

Psychosomatic factors of atopic dermatitis exacerbation

BACKGROUND

The aim of this study was to estimate whether the stress, lack of social support, and poor emotional relationships influence the recurrence of AD in adults.

METHODS

Case-control study comprised 66 outpatients with AD and 132 controls with different skin diseases believed to be slightly influenced by psychosomatic factors. Participants were treated at the Department of Dermatology - Military Medical Academy and City Department for Skin and Venereal Diseases from January to June 2014. Stressful life events were assessed using the Paykel's Interview for Recent Life Events. The attachment relationship and perceived social support were assessed with the Experiences in Close Relationships Scale and with the Multidimensional Scale of Perceived Social Support, respectively. Univariate and multivariate logistic regression analyses were applied.

RESULTS

AD patients had significantly higher anxiety scores when initiating a close emotional relationship and when avoiding an affective attachment (OR = 1.49; CI = 1.13-1.97; P = 0.005 and OR = 1.63; CI = 1.16-2.30; P = 0.005, respectively). Perceived social support from family and friends was significantly lower among cases compared to controls (OR = 0.93; CI = 0.88-0.98; P = 0.009 and UO = 0.94; CI = 0.89-0.99; P = 0.027, respectively).

CONCLUSIONS

AD patients had higher anxiety scores, and those with low social support tended to have more frequent disease recurrence. The number of stressful life events did not differ between studied groups.

Investigating Youth Sport Coach Perspectives of an Asthma Education Module

Physical activity can reduce symptoms and improve wellbeing in people who have asthma, and organized sport is one way for children and youth with asthma to engage in exercise. While asthmatic youth may experience a number of barriers to sport participation, healthy physical and social sport environments supported by coaches can help asthmatic youth athletes maintain long-term engagement in activity. This paper reports results of an assessment of an online coach education tool related to air quality, physical activity, and allergic disease (e.g., asthma). Focus groups with youth team sport coaches in southern Ontario (n = 12 participants) were conducted to explore how users experience the module and short- and medium-term outcomes of implementation. Although coaches perceive the module as relevant, it is considered less valuable in certain contexts (e.g., indoor environments) or when compared with other coach education (e.g., tactical). Although broad asthma management behaviours (e.g., athlete medical forms) were recognized, specific module-identified prevention and management techniques (e.g., the Air Quality Health Index) were less frequently described. Ensuring environment and health coach education emphasizes athlete performance while reducing risk is critical to promoting module application and providing safe and enjoyable youth team sport spaces.

Using the theoretical domains framework to identify barriers and enablers to pediatric asthma management in primary care settings

OBJECTIVES

This study aimed to apply a theory-based approach to identify barriers and enablers to implementing the Alberta Primary Care Asthma Pediatric Pathway (PCAPP) into clinical practice. Phase 1 included an assessment of assumptions underlying the intervention from the perspectives of the developers. Phase 2 determined the perceived barriers and enablers for: 1) primary care physicians' prescribing practices, 2) allied health care professionals' provision of asthma education to parents, and 3) children and parents' adherence to their treatment plans.

METHODS

Interviews were conducted with 35 individuals who reside in Alberta, Canada. Phase 1 included three developers. Phase 2 included 11 primary care physicians, 10 allied health care professionals, and 11 parents of children with asthma. Phase 2 interviews were based on the 14 domains of the Theoretical Domains Framework (TDF). Transcribed interviews were analyzed using a directed content analysis. Key assumptions by the developers about the intervention, and beliefs by others about the barriers and enablers of the targeted behaviors were identified.

RESULTS

Eight TDF domains mapped onto the assumptions of the pathway as described by the intervention developers. Interviews with health care professionals and parents identified nine TDF domains that influenced the targeted behaviors: knowledge, skills, beliefs about capabilities, social/professional role and identity, beliefs about consequences, environmental context and resources, behavioral regulation, social influences, and emotions.

CONCLUSIONS

Barriers and enablers perceived by health care professionals and parents that influenced asthma management will inform the optimization of the PCAPP prior to its evaluation.

Impact of Combination Glaucoma Therapies on β-Blocker Exposure

PURPOSE

β-adrenergic receptor antagonists (β-blockers) used in the treatment of glaucoma are an often-overlooked source of systemic adverse events. Ophthalmic timolol has been associated with severe systemic adverse events including numerous cases resulting in death. In recent years the number of fixed-dose combination therapies for glaucoma has grown rapidly, and among available combination therapies only the nonselective β-blocker timolol is used as the β-blocker component.

METHODS

A population-based study was conducted in Ontario, Canada between January 1, 2001 and December 31, 2012 to assess the shift to combination therapies in the management of glaucoma, and to investigate the impact of this shift on the relative use of selective and nonselective β-blockers in patients with this disease.

RESULTS

Between 2001 and 2012 timolol (nonselective β-blocker) use grew at an average annual rate of 2.2% (P<0.0001), whereas betaxolol (selective β-blocker) use declined by 14.1% per year (P<0.0001). These changes in the relative use of betaxolol and timolol coincided with changes in the relative use of combination and single-drug therapies. Over the study period, the use of β-blockers as single-drug therapy decreased by 7.7% annually (P<0.0001). In contrast, the use of combination therapies containing a β-blocker increased by 7.6% annually (P<0.0001).

CONCLUSIONS

The introduction of fixed combination glaucoma therapies has been associated with a significant shift to greater use of nonselective β-blockers. In vulnerable older populations, this may have an important impact on patient safety that warrants further study.

Astragaloside IV Ameliorates Airway Inflammation in an Established Murine Model of Asthma by Inhibiting the mTORC1 Signaling Pathway

Astragaloside IV (AS-IV), a main active constituent of Astragalus membranaceus, has been confirmed to have antiasthmatic effects. However, it remained unclear whether the beneficial effects of AS-IV on asthma were attributed to the mTOR inhibition; this issue was the focus of the present work. BALB/c mice were sensitized and challenged with ovalbumin followed with 3 weeks of rest/recovery and then reexposure to ovalbumin. AS-IV was administrated during the time of rest and reexposure. The characteristic features of allergic asthma, including airway hyperreactivity, histopathology, cytokines (IL-4, IL-5, IL-13, IL-17, and INF-γ), and CD4⁺CD25⁺Foxp3⁺Treg cells in bronchoalveolar lavage fluid (BALF), and downstream proteins of mTORC1/2 signaling were examined. AS-IV markedly suppressed airway hyperresponsiveness and reduced IL-4, IL-5, and IL-17 levels and increased INF-γ levels in the BALF. Histological studies showed that AS-IV markedly decreased inflammatory infiltration in the lung tissues. Notably, AS-IV inhibited mTORC1 activity, whereas it had limited effects on mTORC2, as assessed by phosphorylation of mTORC1 and mTORC2 substrates S6 ribosomal protein, p70 S6 Kinase, and Akt, respectively. CD4⁺CD25⁺Foxp3⁺Treg cells in BALF were not significantly changed by AS-IV. Together, these results suggest that the antiasthmatic effects of AS-IV were at least partially from inhibiting the mTORC1 signaling pathway.

Real-world health care utilization and effectiveness of omalizumab for the treatment of severe asthma

BACKGROUND

Omalizumab is indicated for the treatment of moderate to severe asthma. There is limited observational evidence on the costs and effectiveness of omalizumab.

OBJECTIVE

To examine the costs and effectiveness of omalizumab for treatment of severe asthma relative to nonusers.

METHODS

We conducted a within-person repeated-measures matched cohort study in Ontario, Canada from April 1, 2012 to March 31, 2014. Continuous users of omalizumab were matched with up to 4 nonusers according to age, sex, recent specialist visits, oral corticosteroid use, asthma severity, and Charlson comorbidity score. The primary outcome was direct health care costs. Secondary outcomes were asthma-related hospitalizations or emergency department visits and oral corticosteroid use. The association between omalizumab use and each outcome was assessed using mixed-effects models adjusting for confounders.

RESULTS

Ninety-five omalizumab users and 352 nonusers were matched. Among users, there was a significant increase in health care costs of $1,796 per person owing to the cost of the medication at treatment initiation (P < .0001). Costs did not change significantly among nonusers ($85 increase in average monthly costs per person; P = .59). We found no significant changes in the rates of asthma-related hospitalizations or emergency department visits among omalizumab users (P = .44) or nonusers (P = .99) between pre- and postintervention periods.

CONCLUSION

The use of omalizumab was associated with increased costs but no evidence of lower rates of clinically important outcomes. These results suggest omalizumab had limited effectiveness in our study population. Future studies should further explore subsets of patients most likely to benefit from omalizumab therapy.

Helicobacter, Hygiene, Atopy, and Asthma

The hygiene hypothesis links environmental and microbial exposures in early life to the prevalence of atopy, allergy, and asthma. Helicobacter pylori infection is typically acquired in childhood and acquisition of the infection is associated with poor household hygiene. Some population surveys have shown an inverse association between H. pylori infection and atopy, allergy, and asthma leading to the suggestion that H. pylori infection may be protective against disease; others consider it simply a biomarker for poor household hygiene. We review the relevant surveys, cohort studies, meta-analyses, and studies testing the protective hypothesis. Overall, the results of surveys and cohort studies are inconsistent, whereas meta-analyses show a significant but weak inverse correlation. In contrast, studies directly testing the protection hypothesis in relation to asthma in populations with poor hygiene and low H. pylori prevalence failed to confirm a protective effect. H. pylori is a major cause of human disease including chronic gastritis, peptic ulcer, and gastric malignancies. H. pylori infections most likely serve as a biomarker for poor hygienic conditions in childhood. We conclude that while synergistic interactions between environmental factors in childhood are important determinants of the pathogenesis of atopy, allergy, and asthma; H. pylori is inversely related to good hygiene and thus it's presence serves as a biomarker rather than for a specific prevention role for H. pylori or H. pylori antigens.

Cost-effectiveness of a school-based health promotion program in Canada: A life-course modeling approach

Background

The Alberta Project Promoting active Living and healthy Eating in Schools (APPLE Schools) has been recognized as a “best practice” in preventing childhood obesity. To inform decision making on the economic implications of APPLE Schools and to justify investment, we evaluated the project’s cost-effectiveness following a life-course approach.

Methods

We developed a state transition model for the lifetime progression of body weight status comparing elementary school students attending APPLE Schools and control schools. This model quantified the lifetime impact of APPLE Schools in terms of prevention of excess body weight, chronic disease and improved quality-adjusted life years (QALY), from a school system’s cost perspective. Both costs and health outcomes were discounted to their present value using 3% discount rate.

Results

The incremental cost-effectiveness ratio(ICER) of APPLE schools was CA$33,421 per QALY gained, and CA$1,555, CA$1,709 and CA$14,218 per prevented person years of excess weight, obesity and chronic disease, respectively. These estimates show that APPLE Schools is cost effective at a threshold of ICER < CA$50,000.

In probabilistic sensitivity analysis, APPLE Schools was cost effective more than 64% of the time per QALY gained, when using a threshold of ICER<CA$50,000, and more than 93% of the time when using a threshold of ICER<CA$100,000.

Conclusion

School-based health promotion, such as APPLE Schools is a cost-effective intervention for obesity prevention and reduction of chronic disease risk over the lifetime. Expanding the coverage and allocating resources towards school-based programs like the APPLE Schools program, is likely to reduce the public health burden of obesity and chronic diseases.

Concurrent physician-diagnosed asthma and chronic obstructive pulmonary disease: A population study of prevalence, incidence and mortality

OBJECTIVE

We conducted a population-based cohort study to estimate trends in prevalence, incidence, and mortality of concurrent physician-diagnosed asthma and chronic obstructive pulmonary disease (COPD).

STUDY DESIGN AND SETTING

Two validated health administrative case definitions were used to identify asthma and COPD among all individuals aged 35 years and older living in Ontario, Canada. Annual asthma, COPD, and concurrent asthma and COPD prevalence, incidence, and mortality, standardized for age and sex, were estimated, and compared from 2002 to 2012, using generalized linear models.

RESULTS

Standardized prevalence of concurrent asthma and COPD increased by 10.5%, from 2.9% in 2002 to 3.2% in 2012 overall, but more prominently in women compared to men. Overall, standardized incidence decreased by16%, from 2.5 to 2.1 per 1000 individuals, but increased significantly in young adults. All-cause mortality among patients with concurrent asthma and COPD decreased by 11.2%, from 2.6% to 2.2%. Being diagnosed with both diseases was significantly associated with higher all-cause mortality compared to asthma (OR = 1.56, 95% CI: 1.50-1.58), but not compared to COPD (OR = 0.97, 0.96-0.98), except in young adults aged 35 to 49 years where people with asthma and COPD had higher mortality (OR = 1.21, 1.15-1.27).

CONCLUSIONS

In a large North American population, the burden of concurrent physician-diagnosed asthma and COPD is increasing, particularly in women and young adults.

Changes in the relationship between asthma and associated risk factors over fifty years

BACKGROUND

Childhood asthma is a common condition whose prevalence is changing. We hypothesized that the relationship between asthma and associated risk factors has changed over a 50-year period.

METHODS

An ecological study design was used. Children aged 8-13 attending schools in Aberdeen city were surveyed on seven occasions between 1964 and 2014. The following were determined: history of asthma, history of eczema, parental smoking, parental asthma, sex and socio-economic status. Analysis was by a structural change model with two knots. The outcome reported was the change in odds ratio between asthma and a given risk factor during a given period.

RESULTS

There were 23,241 questionnaires distributed and 17,439 returned (75%). The odds ratio (OR) for a child with asthma to have eczema increased between 1989 and 1999 by 1.031 [95% CI 1.028, 1.035] and by 1.042 between 2004 and 2014 [1.038, 1.047]. The OR for a child with asthma to have a parent who smoked rose by 1.032 [1.028, 1.036] between 1989 and 1999 and by 1.043 [1.038, 1.047] between 2004 and 2014), and to have a parent with asthma (1.027 [1.022, 1.031] for 1994-99 and 1.042 [1.037, 1.048] for 2004-2014). The OR for a child with asthma being male, but not and being from the most deprived communities, rose between 1989-1999 and 2004-2014.

CONCLUSIONS

The relationship between asthma prevalence and particular risk factors changed over the 50-year period of study, and this might reflect changes in children's environment and/or susceptibility.

Pediatric asthma hospitalizations among urban minority children and the continuity of primary care

OBJECTIVE

To examine the effect of ambulatory health care processes on asthma hospitalizations.

METHODS

A retrospective cohort study using electronic health records was completed. Patients aged 2-18 years receiving health care from 1 of 5 urban practices between Jan 1, 2004 and Dec 31, 2008 with asthma documented on their problem list were included. Independent variables were modifiable health care processes in the primary care setting: (1) use of asthma controller medications; (2) regular assessment of asthma symptoms; (3) use of spirometry; (4) provision of individualized asthma care plans; (5) timely influenza vaccination; (6) access to primary healthcare; and (7) use of pay for performance physician incentives. Occurrence of one or more asthma hospitalizations was the primary outcome of interest. We used a log linear model (Poisson regression) to model the association between the factors of interest and number of asthma hospitalizations.

RESULTS

5,712 children with asthma were available for analysis. 96% of the children were African American. The overall hospitalization rate was 64 per 1,000 children per year. None of the commonly used asthma-specific indicators of high quality care were associated with fewer asthma hospitalizations. Children with documented asthma who experienced a lack of primary health care (no more than one outpatient visit at their primary care location in the 2 years preceding hospitalization) were at higher risk of hospitalization compared to those children with a greater number of visits (incidence rate ratio 1.39; 95% CI 1.09-1.78).

CONCLUSIONS

In children with asthma, more frequent primary care visits are associated with reduced asthma hospitalizations.

Impact of perinatal environmental tobacco smoke on the development of childhood allergic diseases

Allergic diseases such as asthma, allergic rhinitis, atopic dermatitis, and food allergy, are most common chronic, noncommunicable diseases in childhood. In the past few decades, the prevalence has increased abruptly worldwide. There are 2 possible explanations for the rising prevalence of allergic diseases worldwide, that an increased disease-awareness of physician, patient, or caregivers, and an abrupt exposure to unknown hazards. Unfortunately, the underlying mechanisms remain largely unknown. Despite the continuing efforts worldwide, the etiologies and rising prevalence remain unclear. Thus, it is important to identify and control risk factors in the susceptible individual for the best prevention and management. Genetic susceptibility or environments may be a potential background for the development of allergic disease, however they alone cannot explain the rising prevalence worldwide. There is growing evidence that epigenetic change depends on the gene, environment, and their interactions, may induce a long-lasting altered gene expression and the consequent development of allergic diseases. In epigenetic mechanisms, environmental tobacco smoke (ETS) exposure during critical period (i.e., during pregnancy and early life) are considered as a potential cause of the development of childhood allergic diseases. However, the causal relationship is still unclear. This review aimed to highlight the impact of ETS exposure during the perinatal period on the development of childhood allergic diseases and to propose a future research direction.

Childhood Exposure to Ambient Air Pollutants and the Onset of Asthma: An Administrative Cohort Study in Québec

BACKGROUND

Although it is well established that air pollutants can exacerbate asthma, the link with new asthma onset in children is less clear.

OBJECTIVE

We assessed the association between the onset of childhood asthma with both time of birth and time-varying exposures to outdoor air pollutants.

METHOD

An open cohort of children born in the province of Québec, Canada, was created using linked medical-administrative databases. New cases of asthma were defined as one hospital discharge with a diagnosis of asthma or two physician claims for asthma within a 2 year period. Annual ozone (O3) levels were estimated at the child's residence for all births 1999-2010, and nitrogen dioxide (NO2) levels during 1996-2006 were estimated for births on the Montreal Island. Satellite based concentrations of fine particles (PM2.5) were estimated at a 10 km × 10 km resolution and assigned to residential postal codes throughout the province (1996-2011). Hazard ratios (HRs) were assessed with Cox models for the exposure at the birth address and for the time-dependent exposure. We performed an indirect adjustment for secondhand smoke (SHS).

RESULTS

We followed 1,183,865 children (7,752,083 person-years), of whom 162,752 became asthmatic. After controlling for sex and material and social deprivation, HRs for an interquartile range increase in exposure at the birth address to NO2 (5.45 ppb), O3 (3.22 ppb), and PM2.5 (6.50 μg/m3) were 1.04 (95% CI: 1.02, 1.05), 1.11 (95% CI: 1.10, 1.12), and 1.31 (95% CI: 1.28, 1.33), respectively. Effects of O3 and PM2.5 estimated with time-varying Cox models were similar to those estimated using exposure at birth, whereas the effect of NO2 was slightly stronger (HR = 1.07; 95% CI: 1.05, 1.09).

CONCLUSIONS

Asthma onset in children appears to be associated with residential exposure to PM2.5, O3 and NO2.

CITATION

Tétreault LF, Doucet M, Gamache P, Fournier M, Brand A, Kosatsky T, Smargiassi A. 2016. Childhood exposure to ambient air pollutants and the onset of asthma: an administrative cohort study in Québec. Environ Health Perspect 124:1276-1282; http://dx.doi.org/10.1289/ehp.1509838.

Latrophilin receptors: novel bronchodilator targets in asthma

Background

Asthma affects 300 million people worldwide. In asthma, the major cause of morbidity and mortality is acute airway narrowing, due to airway smooth muscle (ASM) hypercontraction, associated with airway remodelling. However, little is known about the transcriptional differences between healthy and asthmatic ASM cells.

Objectives

To investigate the transcriptional differences between asthmatic and healthy airway smooth muscle cells (ASMC) in culture and investigate the identified targets using in vitro and ex vivo techniques.

Methods

Human asthmatic and healthy ASMC grown in culture were run on Affymetrix_Hugene_1.0_ST microarrays. Identified candidates were confirmed by PCR, and immunohistochemistry. Functional analysis was conducted using in vitro ASMC proliferation, attachment and contraction assays and ex vivo contraction of mouse airways.

Results

We suggest a novel role for latrophilin (LPHN) receptors, finding increased expression on ASMC from asthmatics, compared with non-asthmatics in vivo and in vitro, suggesting a role in mediating airway function. A single nucleotide polymorphism in LPHN1 was associated with asthma and with increased LPHN1 expression in lung tissue. When activated, LPHNs regulated ASMC adhesion and proliferation in vitro, and promoted contraction of mouse airways and ASMC.

Conclusions

Given the need for novel inhibitors of airway remodelling and bronchodilators in asthma, the LPHN family may represent promising novel targets for future dual therapeutic intervention.

Evaluation of the efficacy of a web-based work-related asthma educational tool

BACKGROUND

Work-related asthma (WRA) has been estimated to account for 15-20% of adult asthma cases. Studies have indicated that a substantial number of asthma patients have inadequate knowledge of work-related effects on their disease, which may contribute to suboptimal asthma control. A Canadian web-based educational tool on WRA was developed to address this knowledge gap in the population.

OBJECTIVE

To evaluate the effectiveness of this web-based tool.

METHODS

Participants were recruited prior to a routine visit at a tertiary care asthma clinic in Toronto. A brief WRA knowledge questionnaire was developed and administered immediately before and after using of the web-based educational tool, and one year later.

RESULTS

The study sample (N = 34) was mostly female (68%) with a mean age of 50.7 (SD, 17.2). Participants demonstrated significant improvement in questionnaire scores following interaction with the tool. The mean score increased from 76% (SEM = 2.1) to 84% (SEM = 1.7) (p = 0.001). On average, scores improved on 12 of the 13 questionnaire items. A 1-year follow-up of a sample of 19 participants demonstrated a slight reduction in mean scores, from 86% (SEM = 1.9) to 84% (SEM = 1.9), but still demonstrated a trend towards a higher score than the baseline (78%; SEM = 2.9; p = 0.08).

CONCLUSIONS

Our findings suggest that the educational tool has a positive effect on WRA knowledge, and that knowledge may be retained long-term. Future studies are needed in non-tertiary care clinic populations which may possess less baseline knowledge of WRA.

Chronic lung disease and multiple sclerosis: Incidence, prevalence, and temporal trends

OBJECTIVES

We aimed to estimate the incidence and prevalence of chronic lung disease (CLD), including asthma and chronic obstructive pulmonary disease, in the MS population versus a matched cohort from the general population.

METHODS

We used population-based administrative data from four Canadian provinces to identify 44,452 persons with MS and 220,849 age-, sex- and geographically-matched controls aged 20 years and older. We employed a validated case definition to estimate the incidence and prevalence of CLD over the period 1995-2005, and used Poisson regression to assess temporal trends.

RESULTS

In 2005, the crude incidence of CLD per 100,000 persons was 806 (95%CI: 701-911) in the MS population, and 757 in the matched population (95%CI: 712-803). In 2005, the crude prevalence of CLD was 13.5% (95%CI: 13.1-14.0%) in the MS population, and 12.4% (95%CI: 12.3-12.6%) in the matched population. Among persons aged 20-44 years, the average annual incidence of CLD was higher in the MS population than in the matched population (RR 1.15; 95%CI: 1.02-1.30), but did not differ between populations for those aged ≥45 years. The incidence of CLD was stable, but the prevalence of CLD increased 60% over the study period.

CONCLUSION

CLD is relatively common in the MS population. The incidence of CLD has been stable over time, but the prevalence of CLD has increased. Among persons aged 20-44 years, CLD is more common in the MS population than in a matched population. Given the prevalence of CLD in the MS population, further attention to the effects of CLD on outcomes in MS and approaches to mitigating those effects are warranted.

Primary Care Pathway for Childhood Asthma: Protocol for a Randomized Cluster-Controlled Trial

Background

Asthma is the most common chronic condition in children. For many, the disease is inadequately controlled, which can burden the lives of children and their families as well as the health care system. Improved use of the best available scientific evidence by primary care practitioners could reduce the need for hospital care and improve quality of life and asthma control, thereby reducing overall costs to society and families.

Objective

The Primary Care Pathway for Childhood Asthma aims to improve the management of children with asthma by (1) providing primary care practitioners with an electronic guide (a clinical pathway) incorporated into the patient’s electronic medical record, and (2) providing train-the-trainer education to chronic disease management health professionals to promote the provision of asthma education in primary care.

Methods

The research will utilize a pragmatic cluster-controlled design, quantitative and qualitative research methodologies, and economic evaluation to assess the implementation of a pathway and education intervention in primary care. The intervention will be analyzed for effectiveness, and if the results are positive, a strategy will be developed to implement delivery to all primary care practices in Alberta.

Results

The research has been successfully funded and ethics approvals have been obtained. Practice recruitment began fall 2015, and we expect all study-related activities to be concluded by March 2018.

Conclusions

The proposed pathway and education intervention has the potential to improve pediatric asthma management in Alberta. The intervention is anticipated to result in better quality of care for equal or lesser cost.

ClinicalTrial

ClinicalTrials.gov NCT02481037; https://clinicaltrials.gov/ct2/show/NCT02481037 (Archived by WebCite at http://www.webcitation.org/6fPIQ02Ma).

Seventy Years of Asthma in Italy: Age, Period and Cohort Effects on Incidence and Remission of Self-Reported Asthma from 1940 to 2010

BACKGROUND

It is well known that asthma prevalence has been increasing all over the world in the last decades. However, few data are available on temporal trends of incidence and remission of asthma.

OBJECTIVE

To evaluate the rates of asthma incidence and remission in Italy from 1940 to 2010.

METHODS

The subjects were randomly sampled from the general Italian population between 1991 and 2010 in the three population-based multicentre studies: ECRHS, ISAYA, and GEIRD. Individual information on the history of asthma (age at onset, age at the last attack, use of drugs for asthma control, co-presence of hay-fever) was collected on 35,495 subjects aged 20-84 and born between 1925-1989. Temporal changes in rates of asthma incidence and remission in relation to age, birth cohort and calendar period (APC) were modelled using Poisson regression and APC models.

RESULTS

The average yearly rate of asthma incidence was 2.6/1000 (3,297 new cases among 1,263,885 person-years). The incidence rates have been linearly increasing, with a percentage increase of +3.9% (95%CI: 3.1-4.5), from 1940 up to the year 1995, when the rates begun to level off. The stabilization of asthma incidence was mainly due to a decrease in the rates of atopic asthma after 1995, while non-atopic asthma has continued to increase. The overall rate of remission was 43.2/1000person-years, and it did not vary significantly across generations, but was associated with atopy, age at asthma onset and duration of the disease.

CONCLUSIONS

After 50 years of a continuous upward trend, the rates of asthma incidence underwent a substantial stabilization in the late 90s. Despite remarkable improvements in the treatment of asthma, the rate of remission did not change significantly in the last seventy years. Some caveats are required in interpreting our results, given that our estimates are based on self-reported events that could be affected by the recall bias.

Environmental Exposure and Genetic Predisposition as Risk Factors for Asthma in China

Asthma is the most common chronic pulmonary disease worldwide and places a considerable economic burden on society. China is the world's largest developing country and has the largest population. China has undergone dramatic changes in the past few decades. The traditional lifestyle and living environment have changed in ways that directly affect the prevalence of asthma. The prevalence of asthma is lower in Chinese children and adults than in developed countries, but the prevalence has been on the rise during the past 30 years. The prevalence significantly varies among different parts of China. Polymorphisms of multiple genes, outdoor air pollution caused by PM2.5, PM10, SO₂, NO₂, environmental tobacco smoke, and coal, indoor pollution, and inhaled allergens, such as house dust mites, pollen, and cockroach particles, are risk factors for asthma.

Annual consultation incidence of osteoarthritis estimated from population-based health care data in England

OBJECTIVES

To estimate the consultation incidence of OA using population-based health care data in England and compare OA incidence figures with those derived in other countries.

METHODS

A population-based health care database (Consultations in Primary Care Archive) in England was used to derive the consultation incidence of OA (overall and by joint site) using the maximum available run-in period method. These estimates, and their distribution by age and sex, were compared with those published from population-based health care databases in Canada, the Netherlands and Spain. A novel age-stratified run-in period method was then used to investigate whether the consultation incidence has been increasing over time in younger adults.

RESULTS

The annual consultation incidence of OA (any joint) was 8.6/1000 persons ≥15 years of age (95% CI 7.9, 9.3) [6.3 (95% CI 5.5, 7.1) in men and 10.8 (95% CI 9.8, 12.0) in women]. Incidence increased sharply between 45 and 64 years of age, peaking at 75-84 years. The joint-specific incidence was 1.4 (95% CI 1.1, 1.7), 3.5 (95% CI 3.1, 3.9) and 1.3 (95% CI 1.1, 1.6) for hip OA, knee OA and hand OA, respectively. The estimates and their distribution by age and sex were broadly consistent with international estimates. Between 2003 and 2010, incidence in those aged 35-44 years increased from 0.3 to 2.0/1000 persons.

CONCLUSION

Newly diagnosed cases of OA in England occur in 9 in 1000 at-risk adults each year, similar to other international estimates. Although lower, the consultation incidence proportion in younger adults appears to have increased in the past decade.

Diverging prevalences and different risk factors for childhood asthma and eczema: a cross-sectional study

OBJECTIVE

To compare the prevalences of and risk factors for asthma, wheeze, hay fever and eczema in primary schoolchildren in Aberdeen in 2014.

DESIGN

Cross-sectional survey.

SETTING

Primary schools in Aberdeen, North-East Scotland.

PARTICIPANTS

Children in Scottish school years primary 1-7 were handed a questionnaire by their class teacher to be completed by their parents and returned to the researchers by post or online.

MAIN OUTCOME MEASURES

Lifetime history of asthma, eczema and hay fever, and recent history of wheeze.

RESULTS

41 schools agreed to participate (87%). 11,249 questionnaires were distributed and 3935 returned (35%). A parent-reported lifetime history of asthma, eczema and hay fever was present in 14%, 30% and 24% of children, respectively. The odds of lifetime asthma increased with age (OR 1.1 per year, 95% CI 1.1 to 1.2), male sex (OR 1.89, 95% CI 1.4 to 2.3), parental smoking (OR 1.7, 95% CI 1.2 to 2.3) and eczema (OR 6.6, 95% CI 5.2 to 8.4). Prevalence of recent wheeze was also reported to be 14% and was positively associated with male sex, parental smoking and eczema. In contrast, parental eczema was the only identified predictor of childhood eczema risk.

CONCLUSIONS

The lifetime prevalence of asthma in primary schoolchildren was 14% in this survey, approximately half the prevalence of eczema. We report diverging prevalences in relation to previous studies in our locality, and different risk factors for asthma and eczema. These findings suggest that asthma and eczema are unlikely to have a common origin.

Time trends in the incidence, prevalence and age at diagnosis of asthma in children

BACKGROUND

Current knowledge on the prevalence of asthma is mainly based on cross-sectional questionnaire data. Current population-based data on the incidence of asthma in children are scarce.

OBJECTIVE

To study the incidence, prevalence, and age at diagnosis of asthma in children in the Netherlands over the study period 2000-2012.

METHODS

A population-based cohort study was conducted in the Integrated Primary Care Information database. The cohort consisted of 176,516 children (379,536 personyears (PY) of follow-up), aged 5-18 years between 2000 and 2012. All medical records of children with physician diagnosed asthma were validated. Incidence rates, annual percent change (APC), and prevalence for asthma were calculated. Influence of age and gender on incidence rates and change in age at diagnosis were studied.

RESULTS

We identified an asthma cohort of 14,303 children with 35,118 PY. The overall incidence rate was 6.7/1000 PY (95% CI, 6.45-6.97). Until 2008, the incidence rate was significantly increasing (APC 5.79 (95% CI 1.43-10.34); from 2008 onwards, a non-significant decrease was observed (APC -12.16 (95% CI -23.07 to 0.28). Incidence for girls was lower than for boys, this difference decreased with increasing age. (p < 0.001) Overall, the age at diagnosis increased over calendar time and was lower for boys. (linear trend p < 0.001).

CONCLUSION

Our population-based cohort study observed an incidence rate of 6.7 per 1000 PY of physician-diagnosed asthma in children in the Netherlands over 2000-2012. The asthma incidence rate was increasing until 2008. Further studies are needed to confirm the decrease in asthma incidence rate from 2008 onwards.

Efficacy of high-dose vitamin D in pediatric asthma: a systematic review and meta-analysis

CONTEXT

Observational studies have suggested a relationship between vitamin D status and asthma-related respiratory outcomes. The benefit of vitamin D supplementation for pulmonary function, symptoms and exacerbations is not well established.

OBJECTIVE

To systematically review paediatric clinical trials investigating the role of vitamin D on asthma-related respiratory outcomes.

DATA SOURCES

MEDLINE, EMBASE and CENTRAL were searched until January 2014. No date or language restrictions.

STUDY SELECTION

Clinical trials reporting asthma-related respiratory outcomes following vitamin D administration at a dose equal or greater than 500 IU per day were included and reviewed independently by two authors for full systematic review eligibility.

DATA EXTRACTION

Two reviewers independently extracted and verified pre-defined data fields.

RESULTS

We identified five studies that met study eligibility and assessed final data synthesis. The median trial size was 48 participants (range 17-430) and the average daily dose of cholecalciferol ranged from 500 to 2000 IU/day. Overall study methodological quality was high, but some heterogeneity in population and vitamin D dosing regimen was evident. Meta-analysis suggested a statistically significant reduction (RR 0.41, CI 0.27-0.63) in asthma exacerbation with vitamin D therapy.

LIMITATIONS

Due to variability in outcome selection and missing data, it was not possible to perform meta-analysis for pulmonary function testing and asthma symptom scores. Vitamin D-related adverse events were not considered in four of five papers.

CONCLUSIONS

Available evidence from this systematic review suggests that high dose vitamin D may prevent asthma exacerbation. This should be confirmed through larger well-designed randomised controlled trials.

The burden of asthma among the South Asian and Chinese population residing in Ontario

BACKGROUND

The South Asian and Chinese populations represent a significant portion of the population of Ontario; however, little is known about the burden of respiratory OBJECTIVE: To investigate the prevalence of asthma and the associated health care burden among South Asian and Chinese populations living in Ontario.

METHODS

Using administrative health data for Ontario, the authors identified individuals of South Asian and Chinese descent using a validated surname algorithm and compared the prevalence of asthma in these groups with the general population using an established asthma case definition for the period 2002 to 2010. Also compared were the rates of asthma-specific emergency department visits and hospitalizations among the ethnic groups.

RESULTS

In 2010, the prevalence of asthma in South Asians residing in Ontario was similar to that of the general population (12.1% versus 12.4%), and was increasing at a faster rate than in the general population (0.51%⁄year versus 0.34%⁄year). Compared with the general population, the South Asian population had fewer emergency department visits for asthma, whereas the asthma-related hospitalization rate was greatest among the South Asian population (0.45 per 100 person-years). The Chinese population had the lowest asthma prevalence and associated health care use.

CONCLUSION

The burden of asthma among South Asians in Ontario is increasing and warrants further investigation to determine the reasons for this rise.

Association between birthplace, prevalence, and age of asthma onset in adults: a United States population-based study

BACKGROUND

Previous studies have found associations between region of birth and asthma prevalence.

OBJECTIVE

To study the association among birthplace, US prevalence, age of onset, and disease course of adult asthma.

METHODS

Data from 447,801 adults from the 1997 to 2011 National Health Interview Survey were reviewed. History of asthma was compared with birthplace using Rao-Scott χ(2) tests, survey logistic, propensity score, and Cox regression. Trends of asthma prevalence were analyzed using logistic regression. Multivariate models controlled for sociodemographics, health care access, smoking history, and body mass index.

RESULTS

Adults born outside the United States had lower odds of ever asthma (adjusted odds ratio [OR] 0.52, 95% confidence interval [CI] 0.49-0.55) or current asthma (OR 0.50, 95% CI, 0.46-0.54). The inverse association between foreign birthplace and asthma prevalence was significant in all regions of birth (P < .0001). Adults born outside the United States who resided in the United States for longer than 10 years compared with only 0 to 4 years had higher odds of ever asthma (OR 1.28, 95% CI, 1.18-1.38) and current asthma (OR 1.70, 95% CI, .31-2.19). Foreign-born compared with US-born adults also had delayed onset of asthma (adjusted hazard ratio 0.27, 95% CI, 0.27-0.28). The US prevalence of asthma increased in a linear manner from 1997 (9.1%, 8.77%-9.37%) to 2011 (12.5%, 12.1%-12.8%, P < .0001), which paralleled the trend for US-born adults. However, the prevalence of asthma in foreign-born adults was consistently lower and increased to a lesser extent (P < .0001).

CONCLUSION

Foreign-born American adults from all regions of birth have a lower prevalence of asthma, which increases after prolonged US residency. Foreign-born Americans may have a higher risk of adult-onset asthma.

The Cohort for Childhood Origin of Asthma and allergic diseases (COCOA) study: design, rationale and methods

BACKGROUND

This paper describes the background, aim, and design of a prospective birth-cohort study in Korea called the COhort for Childhood Origin of Asthma and allergic diseases (COCOA). COCOA objectives are to investigate the individual and interactive effects of genetics, perinatal environment, maternal lifestyle, and psychosocial stress of mother and child on pediatric susceptibility to allergic diseases.

METHODS/DESIGN

The participants in COCOA represents a Korean inner-city population. Recruitment started on 19 November, 2007 and will continue until 31 December, 2015. Recruitment is performed at five medical centers and eight public-health centers for antenatal care located in Seoul. Participating mother-baby pairs are followed from before birth to adolescents. COCOA investigates whether the following five environmental variables contribute causally to the development and natural course of allergic diseases: (1) perinatal indoor factors (i.e. house-dust mite, bacterial endotoxin, tobacco smoking, and particulate matters 2.5 and 10), (2) perinatal outdoor pollutants, (3) maternal prenatal psychosocial stress and the child's neurodevelopment, (4) perinatal nutrition, and (5) perinatal microbiome. Cord blood and blood samples from the child are used to assess whether the child's genes and epigenetic changes influence allergic-disease susceptibility. Thus, COCOA aims to investigate the contributions of genetics, epigenetics, and various environmental factors in early life to allergic-disease susceptibility in later life. How these variables interact to shape allergic-disease susceptibility is also a key aim.The COCOA data collection schedule includes 11 routine standardized follow-up assessments of all children at 6 months and every year until 10 years of age, regardless of allergic-disease development. The mothers will complete multiple questionnaires to assess the baseline characteristics, the child's exposure to environmental factors, maternal pre- and post-natal psychological stress, and the child's neurodevelopment, nutritional status, and development of allergic and respiratory illnesses. The child's microbiome, genes, epigenetics, plasma cytokine levels, and neuropsychological status, the microbiome of the residence, and the levels of indoor and outdoor pollutants are measured by standard procedures.

DISCUSSION

The COCOA study will improve our understanding of how individual genetic or environmental risk factors influence susceptibility to allergic disease and how these variables interact to shape the phenotype of allergic diseases.

Trends in the prevalence of asthma

The asthma epidemic of the last few decades may have peaked; studies suggest that the incidence and prevalence of asthma has decreased in some countries in the last few years, although other studies suggest continuing small increases in prevalence. Increasing awareness and changing diagnostic habits make precise evaluation of epidemiologic trends difficult in the absence of a gold-standard test for asthma, and on a global basis uncertainty persists. Trends in prevalence in some populations (eg, immigrants, farming communities) suggest both adverse and beneficial effects of specific environmental factors. Although the effects of indoor allergens, dampness, and mold and of outdoor air pollutants, especially traffic related, have traditionally dominated risk-factor research, more recent epidemiologic and clinical studies have focused on metabolic and nutritional factors, including maternal obesity and vitamin D levels, mode of delivery and its effect on the infant microbiome, fetal and infant growth, the psychosocial environment, and medication use by mother and infant. It is likely that changes in incidence and prevalence are due to multiple factors, each contributing a relatively small effect. Longitudinal studies from pregnancy through childhood to adulthood will yield greater insights into the complex pathways leading to asthma.

Middle-aged men with asthma since youth: the impact of work on asthma

OBJECTIVES

To evaluate current occupational exposure and its associations with asthma control, exacerbations, and severity in middle-aged men with asthma from youth.

METHODS

We used the Finnish Defence Force registers, 1986 to 1990, to select conscripts with asthma to represent mild or moderate asthmatic group (asthma group 1; N = 505), men who were exempted from military service to represent relatively severe asthmatic group (asthma group 2; N = 393), and a control group without asthma (N = 1500). A questionnaire was sent out in 2009.

RESULTS

The current self-reported or expert-evaluated exposure to asthma-aggravating factors differed only slightly between the asthmatic groups and the controls. In asthma group 2, being a manual worker or self-employed (odds ratio, 4.5; 95% confidence interval, 1.2 to 16.3) significantly associated with asthma exacerbations.

CONCLUSIONS

Current work may associate with the asthma outcome of middle-aged men with relatively severe asthma in their youth.

Asthma incidence and risk factors in a national longitudinal sample of adolescent Canadians: a prospective cohort study

BACKGROUND

Estimates of asthma incidence and its possible determinants in adolescent populations have rarely been obtained using prospective designs. We sought to identify socio-demographic and other patterns in the incidence of asthma among Canadian adolescents and to examine possible behavioural and environmental determinants of asthma incidence using longitudinal analyses.

METHODS

We used data from the National Population Health Survey (NPHS), a nationally representative longitudinal survey of Canadians. All persons aged 12-18 years without asthma at baseline were followed up to a maximum of 12 years. The outcome was a reported diagnosis of asthma during the follow-up period. Analyses were weighted to the population and bootstrapping procedures were used to estimate variances.

RESULTS

Participants (n = 956) represented 2,038,890 adolescents of whom 293,450 (14.4%) developed asthma over the 21,274,890 person-years of follow-up. Overall, the incidence of asthma was 10.2 per 1000 person-years. In adjusted Cox regression analysis, being female (HR = 2.13, 95% CI = 1.26-3.62, p = 0.005) and being exposed to passive smoking (HR = 2.06, 95% CI = 1.27-3.34, p = 0.003) were associated with the development of asthma while no statistically significant associations were identified for rural residence, being overweight, and other health behaviours. There was also an apparent cohort effect among girls where girls who were older at baseline reported being diagnosed with asthma more over the follow-up than their younger counterparts. This was not observed among males.

CONCLUSIONS

Asthma prevention initiatives for adolescents should target girls and focus on smoking exposures. The role that differential diagnostic patterns play in these observations should be investigated to more accurately assess the incidence of asthma.

Hospitalization rate and 30-day mortality among patients with status asthmaticus in Denmark: a 16-year nationwide population-based cohort study

Objective

Current data on hospitalization and prognosis of acute asthma and status asthmaticus are inconclusive. We aim to analyze the rate of first-time hospitalizations for status asthmaticus among patients of all ages, the proportion admitted to intensive care units (ICU), and the 30-day mortality over a 16-year period.

Methods

In this population-based cohort study, we used medical registries to identify all first-time status asthmaticus hospitalizations in Denmark from 1996 through 2011. Data on comorbidities were also obtained. We computed yearly hospitalization rates overall and by gender and age groups, and estimated the proportion requiring ICU admission. We estimated 30-day age- and gender-standardized mortality. We examined potential misclassification from acute exacerbation of chronic obstructive pulmonary disease (COPD) by excluding patients with preexisting or concurrent COPD.

Results

Of the 5,001 patients identified with a first-time status asthmaticus hospitalization, 50.5% were male, 40.3% were <15 years old, and 12.4% had comorbidity. The hospitalization rate increased from 48.0 per 1,000,000 person-years (PY) (95% confidence interval [CI]: 45.1–51.1 PY) during 1996–1999 to 70.1 per 1,000,000 PY (95% CI: 66.7–73.7 PY) during 2008–2011. This may be explained by an increased hospitalization rate of children. The standardized 30-day mortality risk declined from 3.3% (95% CI: 2.5%–4.1%) in 1996–1999 to 1.5% (95% CI: 0.9%–2.1%) in 2008–2011. During 2005–2011, 10.1% of status asthmaticus patients were admitted to the ICU. Hospitalization rates and mortality risk decreased by excluding 939 patients also registered with COPD, but overall temporal changes did not change.

Conclusion

From 1996 to 2011, status asthmaticus hospitalization rate increased but remained below 100 hospitalizations per 1,000,000 PY. Thirty-day mortality risk was halved to less than 2%.

Time trends of incidence of age-associated diseases in the US elderly population: Medicare-based analysis

OBJECTIVES

time trends of age-adjusted incidence rates of 19 ageing-related diseases were evaluated for 1992-2005 period with the National Long Term Care Survey and the Surveillance, Epidemiology and End RESULTS Registry data both linked to Medicare data (NLTCS-Medicare and SEER-Medicare, respectively).

METHODS

the rates were calculated using individual medical histories (34,077 individuals from NLTCS-Medicare and 199,418 from SEER-Medicare) reconstructed using information on diagnoses coded in Medicare data, dates of medical services/procedures and Medicare enrolment/disenrolment.

RESULTS

increases of incidence rates were dramatic for renal disease [the average annual percent change (APC) is 8.56%, 95% CI = 7.62, 9.50%], goiter (APC = 6.67%, 95% CI = 5, 90, 7, 44%), melanoma (APC = 6.15%, 95% CI = 4.31, 8.02%) and Alzheimer's disease (APC = 3.96%, 95% CI = 2.67, 5.26%), and less prominent for diabetes and lung cancer. Decreases of incidence rates were remarkable for angina pectoris (APC = -6.17%, 95% CI = -6.96, -5.38%); chronic obstructive pulmonary disease (APC = -5.14%, 95% CI = -6.78,-3.47%), and ulcer (APC = -5.82%, 95% CI = -6.77,-4.86%) and less dramatic for carcinomas of colon and prostate, stroke, hip fracture and asthma. Incidence rates of female breast carcinoma, myocardial infarction, Parkinson's disease and rheumatoid arthritis were almost stable. For most diseases, an excellent agreement was observed for incidence rates between NLTCS-Medicare and SEER-Medicare. A sensitivity analysis proved the stability of the evaluated time trends.

CONCLUSION

time trends of the incidence of diseases common in the US elderly population were evaluated. The results show dramatic increase in incidence rates of melanoma, goiter, chronic renal and Alzheimer's disease in 1992-2005. Besides specifying widely recognised time trends on age-associated diseases, new information was obtained for trends of asthma, ulcer and goiter among the older adults in the USA.

Is asthma a vanishing disease? A study to forecast the burden of asthma in 2022

Background

Recent evidence regarding temporal trends of asthma burden has not been consistent, with some countries reporting decreases in prevalence of asthma. In Ontario, the province in Canada with the highest population, the prevalence of asthma rose at a rate of 0.5% per year between 1996 and 2005. These estimates were based on population-based health services use data spanning more than a decade and provide a powerful source to forecast the trends of asthma burden. The objective of this study was to use observed population trends data of asthma incidence and prevalence to forecast future disease burden.

Methods

The Ontario Asthma Surveillance Information System (OASIS) used health administrative databases to identify and track all individuals in the province with asthma. Individuals with asthma identified between April 1, 1996 and March 31, 2010 were included. Exponential smoothing models were applied to annual data to project incidence to the year 2022, prevalence was estimated by applying the cumulative projected incidence to the projected population.

Results

While asthma incidence is falling, the absolute number of prevalent cases will continue to rise. We projected that almost 1 in 8 individuals in Ontario will have asthma by the year 2022, suggesting that asthma will continue to be a major burden on individuals and the health care system.

Conclusions

These projections will help inform health care planners and decision-makers regarding resource allocation to optimize asthma outcomes.

Recurrent tube insertion for chronic otitis media with effusion in children over 6 years

OBJECTIVE

The purpose of this study is to identify the clinical characteristics of children above 6 years of age with chronic otitis media with effusion (COME) who have required pressure equalizing tube (PET) insertions.

METHODS

A retrospective chart review was performed of all children above the age of 6 years, who underwent PET insertion due to chronic OME, between 2000 and 2009 at a tertiary care institution. Children were also divided into those with a single PET and those with ≥ 2 PET. Comparison of various characteristics between the two groups was undertaken.

RESULTS

290 children were identified as having at least one PET insertion after the age of 6 years. 45.5% of the children underwent a single PET insertion while 54.5% underwent 2 procedures or more. No significant gender-based difference was observed. In those patients requiring ≥ 2 PET, 65.2% also underwent tonsillectomy and/or adenoidectomy compared to only 53.8% of children with a single PET intervention (p<0.05). Asthma, trisomy 21 and cleft palate, were more common in those children who had undergone ≥ 2 PET (p<0.001, p<0.01 and p<0.05, respectively).

CONCLUSIONS

Children above 6 years of age who have undergone ≥ 2 PET insertions for COME demonstrated an increased rate of tonsillectomy and adenoidectomy. Trisomy 21, cleft palate and particularly, asthma, were also found to be risk factors for COME necessitating ≥ 2 PET insertions.

Increasing prevalence of asthma, allergic rhinoconjunctivitis and eczema among schoolchildren: three surveys during the period 1985-2008

AIM

The prevalence of asthma, allergic rhinoconjunctivitis (AR) and eczema among children has increased worldwide in the last four decades, but recent studies disagree as to whether the prevalence is continuing to rise or is levelling off or declining. The aim of this study was to assess time trends in a subarctic population.

METHODS

A cross-sectional, questionnaire-based survey was carried out in 2008 among children aged 7-14 years in randomly selected schools in Nordland County, Norway (n = 4150). The results are compared with results from identical studies in 1985 (n = 4870) and 1995 (n = 4456).

RESULTS

The main findings were an increasing prevalence of asthma ever (7.3% in 1985 to 17.6% in 2008, p for trend < 0.001) and AR ever (15.9% in 1985 to 24.5% in 2008, p for trend < 0.001), while the prevalence of eczema ever, after an increase between 1985 and 1995, remained unchanged in the last time period. The prevalence of current disease doubled and trebled between 1995 and 2008 for all three diseases.

CONCLUSION

A repeated cross-sectional survey between 1985 and 2008 documented an increasing prevalence of asthma ever and AR ever among schoolchildren (7-14 years), together with a considerably increase in current asthma, AR and eczema between 1995 and 2008.

Trends in asthma-related direct medical costs from 2002 to 2007 in British Columbia, Canada: a population based-cohort study

Background

Asthma-related health resource use and costs may be influenced by increasing asthma prevalence, changes to asthma management guidelines, and new medications over the last decade. The objective of this work was to analyze direct asthma-related medical costs, and trends in total and per-patient costs of hospitalizations, physician visits, and medications.

Methods

A cohort of asthma patients from British Columbia (BC), Canada, was created. Asthma patients were identified using a validated case definition. Costs for hospitalizations, physician visits, and medications were calculated from billing records (in 2008 Canadian dollars). Trends in total and per-patient costs over the study period were analyzed using Generalized Linear Models.

Results

398,235 patients satisfied the asthma case definition (mid-point prevalence 8.0%). Patients consumed $315.9 million (M) in direct asthma-related health resources between 2002 and 2007. Hospitalizations, physician visits, and medication costs accounted for 16.0%, 15.7% and 68.2% of total costs, respectively. Cost of asthma increased from $49.4 M in 2002 to $54.7 M in 2007. Total annual costs attributable to hospitalizations and physician visits decreased (−39.8% and −25.5%, respectively; p<0.001), while medication costs increased (+38.7%; p<0.001).

Interpretation

This population-based analysis shows that the total direct cost of asthma in BC has increased since 2002, mainly due to a rise in asthma prevalence and cost of medication. Combination therapy with inhaled corticosteroids/long-acting beta-agonists has become a significant component of the cost of asthma. Although billing records capture only a fraction of the true burden of asthma, the simultaneous increase in medication costs and reductions in hospitalization and physician visit costs provides valuable insight for policy makers into the shifts in asthma-related resource use.

Positive exercise test and obstructive spirometry in young male conscripts associated with persistent asthma 20 years later

BACKGROUND

Asthma often begins in childhood or early adulthood and is a common disease among conscripts. The identification of long-term predictive factors for persistent asthma may lead to improved treatment opportunities and better disease control.

OBJECTIVE

Our aim was to study the prognostic factors of the severity of asthma among 40-year-old male conscripts whose asthma began in youth.

METHODS

We studied 119 conscripts who were referred to the Central Military Hospital during 1987-1990 due to asthma and who attended a follow-up visit approximately 20 years later. Asthma severity was evaluated during military service according to the medical records, and 20 years later during a follow-up visit using Global Initiative for Asthma guidelines. We used the results of lung function and allergy tests at baseline as predictors of current persistent asthma.

RESULTS

Compared with baseline, asthma was less severe at follow-up: 11.8% of subjects were in remission, 42.0% had intermittent asthma, 10.9% had mild persistent asthma, and 35.3% had moderate/severe persistent asthma (p < .001). In multivariate models, a positive exercise test at baseline yielded an odds ratio (OR) of 3.2 (95% CI 1.0-9.8, p = .046), a decreased FEV1/FVC % predicted an OR of 4.0 (95% CI 1.7-9.3, p = .002), and a decreased FEF50% % predicted an OR of 2.8 (95% CI 1.3-6.4, p = .012) for current persistent asthma.

CONCLUSIONS

About half of the men had persistent asthma at the 20-year follow-up. Positive exercise tests and obstructive spirometry results were related to the persistence of asthma and may be useful long-term prognostic factors for asthma severity.

Effectiveness of educational interventions on asthma self-management in Punjabi and Chinese asthma patients: a randomized controlled trial

BACKGROUND

Asthma tends to be less well controlled among ethnic minority groups, and its prevalence in new immigrants increases significantly the longer they are in Canada; mainly due to their lack of familiarity with English and difficulty understanding information regarding the disease, health literacy, cultural issues, housing conditions, and lack of access to appropriate care services.

OBJECTIVE

To explore the effectiveness of different formats of culturally relevant information and its impact on asthma patients' self-management within the Punjabi, Mandarin, and Cantonese communities.

METHODS

Using a participatory approach, we developed and tested knowledge and community educational videos (with similar information, but used a different approach, i.e., scientific vs. colloquial) and a pictorial pamphlet. A total of 92 physician-diagnosed adult asthma patients (47 Chinese and 45 Punjabi) were assigned at random to three experimental groups (watched one or both videos) and one comparison group (read pictorial pamphlet) and participated in three in-person interviews and one telephone interview within a 9-month period. Patients received education on asthma self-management via videos and pamphlet and outcomes, including their knowledge of asthma triggers (environmental-related and behavioral-related triggers) and symptoms; inhaler use skills and patient-reported medication adherence were measured.

RESULTS

Knowledge of asthma symptoms, inhaler use, and understanding of physician's instructions improved significantly from pretest to 3 months post-intervention follow-up among all participants.

CONCLUSIONS

Participants performed significantly better at follow-up than they did at baseline assessment, with the most notable improvements observed in the group that watched both community and knowledge videos. The results suggest that short, simple, culturally, and linguistically appropriate interventions can promote knowledge gain about asthma and improve inhaler use that can be sustained over the short term. Such interventions that provide authentic learning materials that draw on patients' life experiences and sociocultural context can overcome certain limitations of conventional patient education approaches.

Estimation of asthma incidence among low-income children in Texas: a novel approach using Medicaid claims data

Few recent estimates of childhood asthma incidence exist in the literature, although the importance of incidence surveillance for understanding asthma risk factors has been recognized. Asthma prevalence, morbidity, and mortality reports have repeatedly shown that low-income children are disproportionately impacted by the disease. The aim of this study was to demonstrate the utility of Medicaid claims data for providing statewide estimates of asthma incidence. Medicaid analytic extract (MAX) data for Texas children aged 0-17 years enrolled in Medicaid between 2004 and 2007 were used to estimate incidence overall and by age group, gender, race, and county of residence. A ≥13-month period of continuous enrollment was required in order to distinguish incident from prevalent cases identified in the claims data. The age-adjusted incidence of asthma was 4.26/100 person-years during 2005-2007, higher than reported in other populations. Incidence rates decreased with age, were higher for males than females, differed by race, and tended to be higher in rural than urban areas. This study demonstrates the utility of Medicaid analytic extract data for estimating asthma incidence and describes the methodology required for a population with unstable enrollment.

Future impact of various interventions on the burden of COPD in Canada: a dynamic population model

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a growing economic burden worldwide. Smoking cessation is thought to be the single most effective way of reducing the economic burden of COPD. The impact of other strategies such as interventions that predict risk of disease, reduce progression of disease, or reduce exacerbations has not been systematically studied.

OBJECTIVES

We estimated the economic and clinical burden of COPD over the next 25 years in Canada and the impact of three potential interventions (screening test for predisposition to COPD, new drugs to avoid progression into more severe disease stages, and predictive test for exacerbations) on COPD burden.

METHODS

Using a dynamic simulation model, we projected the total burden of COPD (cost, morbidity, and mortality) from 2011 to 2035 using the population of Canada as a case study. The model stratified population based on sex, age, smoking status, respiratory symptoms, and their COPD stage. The cost and quality adjusted life years (QALYs) associated with each intervention were estimated.

RESULTS

The model indicates that annual societal cost of COPD is $4.52 billion (B) Canadian dollars in 2011 and will reach $3.61B ($7.33B undiscounted) per year in 2035. Over the next 25 years, COPD will be responsible for approximately $101.4B in societal costs ($147.5B undiscounted) and 12.9 million QALYs lost (19.0 million undiscounted). Our results suggested that the best strategy to reduce the financial burden of COPD is by reducing exacerbations. Smoking cessation, while it is the cornerstone of COPD prevention, has only a modest effect in attenuating the financial burden of COPD over the next 25 years in Western countries such as Canada.

CONCLUSION

Our data suggest that any intervention that can reduce the number of exacerbations has a substantial impact on morbidity and costs of COPD and should be considered in conjunction with the ongoing efforts to reduce smoking rates.

A spatial analysis of asthma prevalence in Ontario

OBJECTIVE

The objective of this paper is to examine spatial patterns of asthma prevalence in the province of Ontario by age and sex between 2002 and 2006.

METHODS

We conducted a population-based, ecological-level study using the Ontario Asthma Surveillance Information System Database (OASIS), a validated registry of all Ontario residents with asthma. Data were mapped and analyzed at the sub-Local Health Integration Network (subLHIN) level (n=141). Comparative morbidity figures (CMFs) were calculated and analyzed for local clusters of high and low values ("hot spots" and "cold spots").

RESULTS

There were 1,601,353 individuals identified as having asthma over the study period, representing an overall prevalence rate of 12.93%. Results demonstrate distinct spatial patterns of asthma prevalence across the province which are age- and sex-specific. There was little overlap between asthma hot spots by age group, suggesting that different spatial processes are at play. Patterns of cold spots are consistently seen in the urban and suburban subLHINs in and around Toronto and Hamilton as well as in several of the highly rural northern subLHINs.

CONCLUSIONS

Findings illustrate the need for more geographically focused public health and health care planning and resource allocation, and highlight the need for research aimed at understanding the factors that may explain the spatial patterns identified here.

Risk of childhood asthma prevalence attributable to residential proximity to major roads in Montreal, Canada

OBJECTIVES

Exposure to traffic-related air pollutants plays a role in several health outcomes. A large body of evidence tends to link asthma in children with traffic exposure. Increasing asthma prevalence and incidence in children in Canadian cities has been of concern for public health authorities. The following study focuses on estimating the risk of asthma prevalence attributable to residing in proximity to major roads on the Island of Montreal, Canada.

METHODS

Risk functions pertaining to asthma in children and residential proximity to major roads were selected from the literature and applied to Montreal. Asthma prevalence was taken from population-based studies. Population data were retrieved from Canadian census. Exposure was estimated using the proximity to major road and highway category of the Desktop Mapping Technologies Inc. database (DMTI Spatial Inc.).

RESULTS

Based on different studies, the percentage of prevalent asthma cases attributable to residing within 50 metres of a major road or highway for children aged 2, 4 and 6 years varied between 2.4% (0-4.3), 5.6% (0.1-8.6) and 5.9% (0.1-9.0). For the 5-7 year age group residing within 75 m of a major road or highway, the percent of cases was 6.4% (2.6-9.3). For children aged 8 to 10 residing within 75 m of a highway only, the percent of cases was 0.7% (0.2-0.9).

CONCLUSION

These numbers represent the best crude estimates and are an indication of a possible range of cases linked to residential proximity to major roads. As there are uncertainties linked to the application of exposure-response functions, these estimates will be reassessed as new evidence is gathered through further research.

Describing and quantifying asthma comorbidity [corrected]: a population study

Background

Asthma comorbidity has been correlated with poor asthma control, increased health services use, and decreased quality of life. Managing it improves these outcomes. Little is known about the amount of different types of comorbidity associated with asthma and how they vary by age.

Methodology/Principal Findings

The authors conducted a population study using health administrative data on all individuals living in Ontario, Canada (population 12 million). Types of asthma comorbidity were quantified by comparing physician health care claims between individuals with and without asthma in each of 14 major disease categories; results were adjusted for demographic factors and other comorbidity and stratified by age. Compared to those without asthma, individuals with asthma had higher rates of comorbidity in most major disease categories. Most notably, they had about fifty percent or more physician health care claims for respiratory disease (other than asthma) in all age groups; psychiatric disorders in individuals age four and under and age 18 to 44; perinatal disorders in individuals 17 years and under, and metabolic and immunity, and hematologic disorders in children four years and under.

Conclusion/Significance

Asthma appears to be associated with significant rates of various types of comorbidity that vary according to age. These results can be used to develop strategies to recognize and address asthma comorbidity to improve the overall health of individuals with asthma.