The Prevention and Management of Asthma in Canada

Table of Contents

• Preface
• National Asthma Control Task Force
  
• Executive Summary
  
• Introduction
  
• Definition
  
• Prevalence of Asthma in the Population
  
• Associated Morbidity and Mortality
  
• Personal, Social and Economic Impact
  
• Causes of Asthma
  
• Scope for Prevention
  
• Screening for Asthma/Early Detection
  
• Scope for Control of Asthma
  
• System Support
  
• Summary
  
• Bibliography

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List of Tables

Table 1	Prevalence of asthma (diagnosed by a physician) by gender and age, Canada, 1996
Table 2	Age at onset of asthma
Table 3	Economic costs associated with asthma
Table 4	Common asthma triggers, Canada, 1995-97
Table 5	Proportion of those diagnosed with active asthma who have specific asthma triggers by age group, Canada, 1996-97
Table 6	Environmental factors and prevention measures
Table 7	Screening principles applied to asthma

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List of Figures

Figure 1	Age-adjusted rates of hospital separations/100,000 for asthma - both genders - Canada, 1971-1996
Figure 2	Age-adjusted rates of hospital separations/100,000 for asthma - by age group and gender - Canada, 1971-1996
Figure 3	Age-adjusted rates of hospital separations/100,000 for asthma in the younger age groups - both genders - Canada, 1971-1996
Figure 4	Age-adjusted rates of hospital days/100,000 for asthma - both genders - Canada, 1971-1996
Figure 5	Age-adjusted rates of hospital days/100,000 for asthma - by age group and gender - Canada, 1971-1996
Figure 6	Age-adjusted rates of hospital days/100,000 for asthma in the younger age groups - both genders - Canada, 1971-1996
Figure 7	Age-adjusted asthma mortality rates/100,000 - all ages - both genders - Canada, 1971-1997
Figure 8	Age-adjusted asthma mortality rates/100,000 - ages 0-24 - both genders - Canada, 1971-1997
Figure 9	Age-adjusted asthma mortality rates/100,000 - ages 25 and over - both genders - Canada, 1971-1997
Figure 10	Proportion of individuals diagnosed with active asthma who had activity restriction in past year - Canada, 1996-97
Figure 11	Proportion of individuals diagnosed with active asthma who have ever received information on various topics - ages 2+ years - Canada, 1996-97
Figure 12	Proportion of individuals diagnosed with active asthma who have ever received information on asthma from various sources - ages 2+ years - Canada, 1996-97 (Most common sources)
Figure 13	Proportion of people aged 2-19 diagnosed with active asthma who have ever received information on asthma from specific people - Canada, 1996-97 (Most common sources)
Figure 14	Proportion of people aged 20-34 diagnosed with active asthma who have ever received information on asthma from specific people - Canada, 1996-97 (Most common sources)
Figure 15	Proportion of individuals aged 35-64 diagnosed with active asthma who have ever received information on asthma from specific people - Canada, 1996-97 (Most common sources)
Figure 16	Proportion of individuals aged 65 and over diagnosed with active asthma who have ever received information on asthma from specific people - Canada, 1996-97 (Most common sources)
Figure 17	Proportion of individuals diagnosed with active asthma who have been given skills training - by age group - Canada, 1996-97
Figure 18	Proportion of individuals diagnosed with active asthma who were exposed to tobacco smoke - by age group - Canada, 1996-97
Figure 19	Proportion of individuals diagnosed with active asthma who have ever been given a personal asthma self-management plan - by age - Canada, 1996-97

 

Acknowledgements

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Preface

This report is the background document for the development of a National Asthma Prevention and Control Strategy. It has been developed with the guidance of the National Asthma Control Task Force (NACTF). The Laboratory Centre for Disease Control (LCDC) of Health Canada established the NACTF in 1995 to advise on a response to the growing problem of asthma in Canada.

Any comments should be directed to the Respiratory Division, Cardio-Respiratory Diseases and Diabetes Bureau, Laboratory Centre for Disease Control, Health Canada.

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National Asthma Control Task Force

Bai, Dr. Tony R.	Canadian Thoracic Society
Beaudry, Dr. Pierre	Canadian Paediatric Society
Beveridge, Dr. Robert	Chair, National Asthma Control Task Force Canadian Association of Emergency Physicians
Cicutto, Dr. Lisa	Canadian Nurses Respiratory Society
Chapman, Dr. Ken	Canadian Network for Asthma Care
Dean, Dr. Mervyn	College of Family Physicians of Canada
Fatum, Doug	Canadian Pharmacists Association
Haromy, Chris	Asthma Society of Canada
Homuth, Cheryl	Canadian Society of Respiratory Therapists
Kaplan, Dr. Alan	Family Physicians Asthma Group of Canada
Kelm, Cheryle	Canadian Physiotherapy Cardio-respiratory Society
Kenney, Andrea	Allergy/Asthma Information Association
Leith, Dr. Eric	Canadian Society of Allergy and Clinical Immunology
McRae, Louise	Respiratory Disease Division, Bureau of Cardio-Respiratory Diseases and Diabetes, Laboratory Centre for Disease Control, Health Canada
Scott, Dr. Jeff	Federal-Provincial Advisory Committee on Epidemiology
Taylor, Dr. Gregory	Bureau of Cardio-Respiratory Diseases and Diabetes, Laboratory Centre for Disease Control, Health Canada
VanGorder, Bill	Canadian Lung Association
Past Task Force Members:
Boulet, Dr. Louis-Philippe	Canadian Thoracic Society (to 1998)
Kovac, Elizabeth	Asthma Society of Canada (to 1998)
Owen, Dr. Grahame	College of Family Physicians of Canada (to 1996)

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Executive Summary

Introduction

 

 

Asthma is one of the most prevalent chronic conditions affecting Canadians. It places a heavy burden on the nation's health care expenditures, reduces productivity, and seriously affects the quality of life for individuals with asthma and their families. This report summarizes the definition, prevalence and impact of asthma, and includes a review of both the scope for prevention and control, and existing activities in Canada. It is based on current literature reviews, reports, health data, and surveys.

A National Asthma Prevention and Control Strategy can provide the overall framework for mobilizing energies from many sectors to the prevention and management of asthma in Canada. This background document will serve as the starting point for the development of the national strategy.

Summary of Research Evidence

The National Asthma Control Task Force reviewed recent surveys, epidemiologic data, and the recommendations of the 1998 Canadian consensus guidelines for asthma management. The Task Force identified the following key research findings that need to be considered in a strategy to prevent and control asthma.

Epidemiology

According to the 1996-97 National Population Health Survey, over 2.2 million Canadians have been diagnosed with asthma by a physician (12.2% of children and 6.3% of adults). An estimated 10% of children and 5% of adults have active asthma (take medication for asthma or have experienced symptoms in the past 12 months). There has been an increase in the prevalence of asthma among children in the past 15 years.

Asthma mortality rates increased from 1970 to the mid-1980s. The mortality rate changes were most evident in the 15 to 24 and the 65 and over age groups. By 1995, the mortality rates had decreased to below the 1970 level except in the 15 to 24 year age group. Hospitalization rates for asthma increased for children in the 1980s. By the mid-1990s the rate had started to decrease but remained higher than the rate in the 1970s.

Prevention

The exact cause of asthma is not known, but it appears to be the result of a complex interaction of:

The increase in asthma seen among children in westernized countries in the past several decades may be the result of alterations in the nature of exposures to various factors in the fetal and early childhood period, which may, in turn, influence the development of the immune system. In genetically predisposed individuals, the altered immune system may result in an increased allergic response to foreign substances, and this may predispose the child to asthma. Vaccines that decrease the tendency to develop a hyper-reactive allergic immune response are being studied.

Research on the effectiveness of interventions to prevent asthma is lacking. Breastfeeding and avoiding the exposure of infants and young children to house dust mites, cockroaches, animal dander, and cigarette smoke may decrease the risk.

Screening

Several outstanding issues require further research before general population screening for asthma could be recommended. These include:

• determining whether earlier diagnosis and treatment would change the long-term outcome for children or adults;

• identifying and assessing the methods of screening for asthma; and

• assessing the feasibility and effectiveness of implementing a screening program.

Asthma Management

Asthma may be difficult to diagnose because of the similarity of its symptoms to other respiratory conditions. Both under- and over-diagnosis of asthma are a concern in the health care community. This is in part because no one clinical or objective diagnostic test for asthma exists. According to the Canadian Asthma Consensus Conference Guidelines for Asthma Management, the diagnosis should be based on:

Effective co-management of asthma involving the individual and family with the health care team is dependent on:

Regular physical activity is an important component of an effective asthma management plan.

Some individuals use non-pharmacological therapy, such as acupuncture, chiropractic, herbal preparations, homeopathy, naturopathy, oligotherapy, and traditional Chinese medicine. There is a lack of sufficient research evidence at this time to either support or reject the role of these therapies in the treatment of asthma.

The control of asthma is heavily influenced by the extent to which an individual and his/her family take responsibility for its management. This includes avoiding triggers, creating a self-management plan with the health care team, adhering to the plan, and ensuring the appropriate use of health care services.

Collaborative health care teams that include the individual with asthma and the family increase the control of asthma. To ensure access to appropriate health services there must be recognition of specific needs associated with such factors as language, culture, age, gender, literacy, income, and level of education.

Parent groups and asthma voluntary organizations can facilitate the achievement of improved quality of life for individuals with asthma through education, services and support.

Given that asthma is a chronic health problem, the creation of supportive policies and the enforcement of air quality standards in school, workplace and public environments can facilitate an individual's efforts to improve quality of life and asthma control. Legislation is necessary to complement voluntary efforts to reduce exposure to air contaminants such as cigarette smoke, indoor and outdoor pollution, and workplace contaminants. Some individuals have difficulty paying for asthma medications or medication delivery devices that are essential for the control of asthma.

Scope for Improved Prevention and Management of Asthma

Combining research evidence with a review of actual practice indicates that more could be done to improve asthma prevention and management.

Primary Prevention

There is a lack of research on the effectiveness of interventions to prevent the onset of asthma. According to the epidemiological evidence, the following strategies could contribute to a reduction in the incidence of asthma. These strategies require the combined efforts of many individuals, organizations, community groups, and government. Strategies need to be directed at:

• reducing exposure in the workplace to airborne contaminants;

• reducing exposure to passive smoke, both in utero and among young children;

• encouraging breastfeeding and delayed introduction of solid foods;

• decreasing the exposure of young children to house dust mites, cockroaches, and moulds through regular cleaning and adequate ventilation; and

• decreasing the exposure of children who have a genetic predisposition to asthma, to known sensitizers.

Improved Management of Asthma

• Increased knowledge among physicians about clinical practice guidelines.

• Increased use of long-term inhaled anti-inflammatory controller medication to decrease the over-reliance on reliever medication.

• Increased use of objective measures of airflow for the diagnosis and serial monitoring of asthma control.

• Increased use of written, personalized asthma plan for guided self-management.

• Enhanced health services to ensure that individuals newly diagnosed with asthma and their families have access to appropriate education for asthma management. This includes not only adequate funding but also an increase in the number of appropriately trained and certified asthma educators, and in access to these educators.

• Reduction in environmental contaminants (aeroallergens, moulds, tobacco smoke, vehicle and industry emissions, noxious odours, and scents) that can trigger asthma episodes and symptoms in the home, workplace, childcare setting and schools.

• Support for those families who lack sufficient financial resources to purchase medication and devices (spacers, holding devices, mattress enclosures, and peak flow meters) for effective asthma management.

 

System Support Functions

 

• Asthma needs to be identified as a serious health problem that requires commitment from governments, the health care system, workplaces, schools, childcare settings and voluntary health organizations.

• To facilitate joint planning, communication, collaboration and advocacy, national and provincial/territorial coalitions require ongoing financial support.

• At the local level, individuals, families, health care providers from all sectors, voluntary groups, and others need to work together to ensure the availability of effective policies, services and programs.

• The need for ongoing basic, clinical, community, and epidemiological research on the prevention and control of asthma continues. Incorporating evaluations that use qualitative and quantitative methods into all programs, services, and policies would result in a large body of research data.

• The dissemination of clinical practice guidelines requires adequate funding. Effective dissemination strategies must be multi-dimensional so that they address the predisposing, enabling, and reinforcing factors that influence the service providers' adoption and use of the guidelines.

• A more detailed and timely system of monitoring trends in asthma outcome is urgently required.

 

Summary

Asthma is a common health problem in Canada that affects both children and adults. Reducing exposure to airborne workplace contaminants, environmental tobacco smoke, house dust mites, animal dander, and moulds may decrease the risk of the development of asthma among sensitive individuals. It may also decrease symptoms and attacks among those with asthma.

Consistent use of Asthma Practice Guidelines for diagnosis, and the use of appropriate medication, self-management plans, education, and follow-up would lead to improved asthma management in the population. The active involvement of the individual with asthma and his/her family would also ensure effective management of the condition. Their involvement requires the establishment of adequate training and funding for asthma education.

At a systems level, the asthma surveillance system is very basic. Its expansion would provide meaningful information to policy makers. An ongoing, formal process for the education of service providers on the implementation of clinical practice guidelines would not only ensure the correct and timely diagnosis of asthma, but would also provide a stronger foundation for its management. Improved collaboration at the national, provincial/territorial and regional/local levels would ensure the continuity of care, effective planning, and the optimization of the various components of the health care system toward asthma's prevention and management.

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Introduction

Asthma is one of the most prevalent chronic conditions affecting Canadians. According to the 1996 National Population Health Survey,[1] asthma affects 6% of adults and 12% of children. Despite advances in medicine and technology, asthma mortality and morbidity rates in Canada and many other industrialized countries[2] rose significantly in the 1970s and 1980s. While mortality rates fell in the 1980s and 1990s, epidemiological and hospitalization data suggest that the prevalence of asthma is continuing to increase. Asthma continues to impose a heavy burden on the nation's health care expenditures, reduces productivity, and seriously affects the quality of life for individuals with asthma and their families.

Asthma is a health problem that does not have a "quick fix". It will require the combined efforts of individuals with asthma and their families, health care providers, health care institutions, schools, workplace, governments, voluntary organizations, industry, and the general public. Many individuals and organizations have been working to prevent and control asthma, but more coordination is required to eliminate duplication of effort and reduce the wide variation in the quantity, quality, and effectiveness of asthma control across the country.

This report summarizes the definition, prevalence, and impact of asthma, and examines the scope for prevention and control with a review of existing activities in Canada. It is based on an evaluation of existing literature reviews, reports, health data, and surveys.

A National Asthma Prevention and Management Strategy can provide the overall framework needed to mobilize energies from many sectors to the prevention and management of asthma in Canada. This background document is being used by the National Asthma Control Task Force to develop the national strategy.

 

 

© 2000 The National Asthma Control Task Force
Catalogue No. H49-138/2000E
ISBN 0-662-28953-6

Material appearing in this report may be reproduced or copied without permission. Use of the following acknowledgement to indicate the source would be appreciated, however:

The National Asthma Control Task Force. The Prevention and management of asthma in Canada: a major challenge now and in the future

Aussi disponible en français sous le titre Prévention et prise en charge de l'asthme au Canada : un défi de taille maintenant et à l'avenir