Childhood Asthma in Sentinel Health Units

Findings of the Student Lung Health Survey 1995-1996

* Current Asthma was defined in the Survey as occurring when students had been told by a physician that they had asthma, and had shown one or more of these three characteristics in the previous 12 months: wheezing or whistling in the chest; an asthma attack; or had taken asthma medicine.

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Asthma is an important cause of suffering, disability, and hospitalization among children in Canada. Estimates from past studies indicate that over half a million children 0-19 years of age in Canada suffer from asthma, and more than 60% of all hospital admissions due to asthma are for children in this age group.

Studies have shown that much of the asthma hospitalization and death can be prevented, and that effective asthma management by health care providers, patients and their families can play a very important role in reducing suffering, hospitalization and death due to asthma.

The Student Lung Health Survey was designed to provide relevant information for the planning and implementation of effective asthma management and control program activities, which will ultimately help to reduce suffering and improve the quality of life of Canadians with asthma.

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Survey Findings

Asthma Status of Students
Overall, 13% of all students (aged 5-19) surveyed had current asthma^* (Figure 1).

Figure 1 Students with Current Asthma, by Health Unit

In addition to the 13% of students who had current asthma, a little over 3% of students had non-current asthma^* (Figure 2). About 21% of students had had  asthma-like conditions^† in the previous 12 months, although they had not been given a diagnosis of asthma.

Figure 2 Asthma Status of Students

* Non-Current Asthma: students had been told by a physician that they had asthma, but did not meet any of the three criteria listed under "Current Asthma" in the previous 12 months. † Asthma-Like Conditions: students had never been told by their doctor that they had asthma but met one or more of the following four criteria in the previous 12 months: experienced a dry cough at night that was not due to a cold or chest infection;  experienced wheezing or whistling in the chest; noticed chest sounding wheezy during or after exercise/sports; or were currently taking asthma medication, which improved their symptoms.

Asthma Severity

Overall, 69% of students with current asthma had experienced at least one asthma attack in the previous 12 months, and 4% had had more than one attack a week on the average.  Continuous (daily or almost daily) asthma symptoms were reported by 17%.

Sleep disturbance due to asthma occurred in 64%, and 7% reported such occurrence more than once a week on the average.

In the previous 12 months, 19% of students with current asthma had visited an emergency room; 4% had spent a night or more in a hospital; and 16% had missed more than a week of school because of asthma.

Asthma Triggers

The most commonly reported asthma triggers, or factors that brought on students' asthma or made it worse, were as follows (Figure 3):

• colds and chest infections (86%)
• exercise or sports (75%)
• pollen, flowers, grass, plants or trees (58%)
• tobacco smoke (55%)
• dust (55%)
• cold air (53%)
• pets (47%)
• mold/mildew (33%)
• outdoor air pollution (32%).

Figure 3 Asthma Triggers Reported by Students with Current Asthma

Figure 4 Regular Exposure to Passive Smoke Among Students with Current Asthma, by Health Unit

Figure 5 Smoking Among Students with Current Asthma Aged 13 to 19 Years, by Health Unit

Pets in the home

Although 47% of students with asthma reported that their asthma symptoms were triggered or worsened by exposure to household pets, 56% had a pet(s) inside the home. The most common pets were dogs (34%) and cats (27%).

Home environment

Other than avoiding exposure to tobacco smoke and having no pets in the home, the Survey found that only some students with asthma and their families follow these usual recommendations for avoiding common indoor asthma triggers (allergens):

Doctor Visits and Medicine

The majority (72%) of students with current asthma had visited a doctor in the previous 12 months.  About 90% of students with current asthma had been taking asthma medicine in the previous year.

The most common asthma drugs taken were the following:

(i) inhaled short-acting b₂-agonists, a reliever medication that dilates the airways (e.g. Ventolin^®, Bricanyl^®); and

(ii) inhaled corticosteroids, a preventer medication used to reduce airway inflammation, swelling and mucus (e.g. Beclovent^®, Pulmicort^®).

Patient Education

The three most commonly reported providers of asthma education to patients and their families were as follows:

• family doctors (74%)
• medical specialists (52%)
• pharmacists (42%)

Advice during medical visits, pamphlets/brochures, and books/booklets were the most common methods of patient education.  The Survey findings indicated that asthma education topics commonly provided to students with asthma and/or their parents included the following:

• How to use an inhaler
• Demonstration of proper use of inhaler
• Correct use of medicine
• Avoiding factors (triggers) that bring on asthma or make it worse
• What to do when having an asthma attack
• When to go to the Emergency Room
• How to live a normal life with asthma
• How to use a peak flow meter

However,  a “personal asthma self-management plan” – a written plan that tells the patient how to adjust the amount of medicine, depending on severity of symptoms, and when to seek medical care – was only given to a small percentage (7%) of the students with current asthma.

Remarks

Although these results from the nine health units may not necessarily be generalizable to the total Canadian population of this age group (because of the “voluntary” nature of the health units’ participation and the fact that only eight provinces are represented), they do provide a wealth of information on the various aspects of asthma that will be useful for the planning, implementation and evaluation of effective asthma control programs and activities, both in the nine health units and in other jurisdictions.  

This report presents the descriptive results of the study, which is only the first stage of the overall data analysis of the survey.  Further analysis of the survey data will be conducted to provide additional insight into ways to improve asthma prevention and control in Canada.

Acknowledgements

Thank you to the many individuals who contributed to the success of this survey: the students, parents, and school personnel who volunteered their time and information; the coordinators and staff of the participating Health Units; and our colleagues in Health Canada (LCDC) and Statistics Canada.

Ce document est disponible en français sous le titre «L’asthme infantile dans les secteurs desservis par les unités de santé sentinelles – Résultats de l’Enquête sur la santé pulmonaire des jeunes 1995-1996».

This summary of the findings of the Student Lung Health Survey 1995-1996 regarding childhood asthma in sentinel health units was prepared by the Respiratory Disease Division of the Bureau of Cardio-Respiratory Diseases and Diabetes, Laboratory Centre for Disease Control, Health Protection Branch, Health Canada. For additional information, please contact the Division at (613) 941-8630; Fax: (613) 954-8286; or by e-mail at bcrdd@hc-sc.gc.ca.