Asthma Knowledge Centre
Asthma
Development & Progression of Asthma
Asthma in adolescents and children (ISAAC)
The ISAAC was initiated in 1991 and was designed to allow comparisons of asthma prevalence and symptoms between populations in different countries. There are three phases (I–III) to the study: Phase I is complete and Phases II and III are ongoing. The objectives of Phase I were to determine the prevalence and severity of asthma, rhinitis and eczema in children living in different areas, and to make comparisons between and within countries.1 The study also aimed to obtain baseline measures for future assessments and provide a framework for further etiologic research into lifestyle, genetic, environmental and medical care factors affecting children with asthma, rhinitis and eczema.1 Two distinct age groups were examined: 13–14 year olds and 6–7 year olds. The former age group was chosen for their ability to self-complete the written and video questionnaires, and the latter age group included the youngest age when children are usually at school.1 The findings in children aged 13–14 years are shown in Figure 1.
Figure 1. The prevalence of current asthma symptoms by country in children aged 13–14 years (A: written questionnaire, B: video questionnaire)1
Reproduced with permission from ISAAC. Worldwide variations in the prevalence of asthma symptoms: the international study of Asthma and Allergies in Childhood (ISAAC). Eur Respir J 1998;12:335. Copyright European Respiratory Society Journals Ltd 1998.
This large framework for studying the incidence of asthma symptoms in adolescents and children is shedding light on the factors (e.g. environmental, early-life predisposition towards atopic response, aeroallergens and diet) involved in the increasing worldwide prevalence of asthma.1 Healthcare professionals now need to examine the way asthma is treated in these populations, as well as to investigate therapies that allow for the best possible long-term care.1
Consequences of asthma in adolescents and children
Asthma may develop in infancy; however, it is often difficult to make an accurate diagnosis until the child is older.2 Viruses and allergens are important triggers of wheezing and asthma episodes, particularly in children under 5 years of age.2 Although viral respiratory infections are often associated with wheezing in infants and very young children, they are not predictive of childhood-onset asthma.2 Atopy, the production of abnormal amounts of immunoglobulin E (IgE) in response to allergens, is a strong risk factor for the development of asthma in children.2
As in adults, asthma symptoms in children affect energy levels and the ability to concentrate; but in children, these effects are more likely to interfere with learning, performance, relationships with peers and overall well-being. In children and adolescents, asthma can result in school absences and, as a result, the disease may impact on long-term educational achievement.2
| School absences | Low energy levels/fatigue | Inability to concentrate | Reduced physical activity |
| Restricted social participation | sleep loss | Diminished quality of life |
Long-term concern for the child with asthma
The long-term prognosis for children with asthma is a major concern. Up to two-thirds of children with asthma will continue to suffer from the disorder throughout adolescence and adulthood.2 In addition, epidemiologic evidence suggests that while 30–50% of asthma cases may disappear at puberty, it often reappears in adult life.2 Asthma should not be dismissed as trivial in the hope it will be outgrown. Indeed, a total of 5–10% of children with asthma that is considered to be trivial develop severe asthma in later life.2
References:
1. ISAAC. Worldwide variations in the prevalence of asthma symptoms: the International Study of Asthma and Allergies in Childhood (ISAAC). Eur Respir J 1998;12:315–335.
2. GINA. Global Initiative for Asthma. www.ginasthma.com. 2005.
3. Silverstein MD, Mair JE, Katusic SK, Wollan PC, O’Connell E J, Yunginger JW. School attendance and school performance: a population-based study of children with asthma. J Pediatr 2001;139:278–283.
4. Sadeh A, Horowitz I, Wolach-Benodis L, Wolach B. Sleep and pulmonary function in children with well-controlled, stable asthma. Sleep 1998;21:379–384.