Asthma and allergic disease prevalence in a diverse sample of Toronto school children: results from the Toronto Child Health Evaluation Questionnaire (T-CHEQ) Study.

BACKGROUND: Asthma is the most common chronic disease in children.
OBJECTIVES: To describe the prevalence of asthma and allergic disease in a multiethnic, population-based sample of Toronto (Ontario) school children attending grades 1 and 2.
METHODS: In 2006, the Toronto Child Health Evaluation Questionnaire (T-CHEQ) used the International Study of Asthma and Allergies in Childhood survey methodology to administer questionnaires to 23,379 Toronto school children attending grades 1 and 2. Modifications were made to the methodology to conform with current privacy legislation and capture the ethnic diversity of the population. Lifetime asthma, wheeze, hay fever and eczema prevalence were defined by parental report. Asthma was considered to be current if the child also reported wheeze or asthma medication use in the previous 12 months.
RESULTS: A total of 5619 children from 283 randomly sampled public schools participated. Children were five to nine years of age, with a mean age of 6.7 years. The overall prevalence of lifetime asthma was 16.1%, while only 11.3% had current asthma. The reported prevalence of lifetime wheeze was 29.2%, while 14.2% reported wheeze in the past 12 months. Sociodemographic and major health determinant characteristics of the T-CHEQ population were similar to 2001 census data, suggesting a diverse sample that was representative of the urban childhood population.
CONCLUSIONS: Asthma continues to be a highly prevalent chronic disease in Canadian children. A large proportion of children with reported lifetime asthma, who were five to nine years of age, did not report current asthma symptomatology or medication use.