World Asthma Day insights from Paul O’Byrne, Dean and Vice-President

As a clinician who has dedicated my career to clinical care and research into asthma, I am sharing some insights about asthma, to help spread awareness on World Asthma Day.

World Asthma Day is organized by the Global Initiative for Asthma (GINA). GINA is a World Health Organization (WHO) collaborative organization and an initiative that I had the benefit to be part of as chair of the science committee and then executive for more than 10 years.

GINA has chosen “Asthma care for All” as the theme this year to recognize that most asthma morbidity and mortality occurs in low- and middle-income countries. Access to appropriate and quality medications can help to develop and implement effective asthma management programs.

Asthma is a very common chronic disease characterized by variable airflow obstruction, airway inflammation and increased constriction of the airway to inhaled stimuli, termed airway hyperresponsiveness (AHR). The origins of asthma occur most commonly in childhood through interaction with a variety of factors like allergens, airborne irritants, respiratory viral infections, and occupational exposure, each of which acts through different pathways to result in airway inflammation, and variable airflow obstruction.

The prevalence of asthma varies widely when countries are compared. The International Study of Asthma and Allergies in Children (ISAAC) was established to determine whether these variances were explained by differences in the tools used to measure asthma prevalence. Using a standardized protocol, a significant difference was found in asthma symptoms in children for example ranging from three per cent to five per cent in countries that included Indonesia, China, and Greece to more than 20 per cent in Canada, Australia, New Zealand, and the UK. These results likely represent real differences between countries, but also raise the possibility of either underdiagnosis in countries with a lower prevalence or difference in risk factors in these areas of the world.

Asthma prevalence is not as well studied in adults as it is in children. Studies have shown marked differences in asthma prevalence between countries and while that requires further study, this has led to the development of studies evaluating risk factors for asthma.

Asthma and other allergic diseases, such as allergic rhinitis and atopic eczema, are among the few chronic diseases marked by increasing worldwide prevalence. This again has been best described in children. Several studies have used the same evaluative tool to measure asthma symptoms, such as recurrent wheezing, and measured over five to more than 30 years. In the US, the National Health and Nutrition Examination Surveys performed measurements 5 years apart and found the asthma prevalence rose from 4.8 per cent to 7.6 per cent. In Scotland, the prevalence of asthma rose from 4 per cent to 10 per cent, eczema from 6 per cent to 12 per cent and allergic rhinitis from 3 per cent to 12 per cent between 1964 and 1989. All the important allergic diseases of childhood increased by about the same extent. These increases may partly be accounted for by an increased acceptance of the label asthma and by methods used for its diagnosis. However, these measures are unlikely to account for all increases and would not explain the parallel increases in allergic eczema and allergic rhinitis.

I have the great opportunity to connect with other leading asthma researchers, teachers, and clinicians, for example at the International Asthma Conference at Nemacolin, to discuss the latest research developments that will benefit patients with asthma. I am thrilled to see developments that will have a positive impact on patients. I’m especially proud about the many advances coming out of McMaster, including this simple non-invasive screening tool for young children.

This important work truly improves health and well-being and is an excellent example of collaboration and partnership between researchers. In the spirit of “Asthma care for All” there is still much to be done. Some of the studies I have mentioned indicate country prevalence and differences that should be further explored, and asthma management programs and quality medicine should be made available to all those suffering from asthma. Ready access to very effective and safe treatments for asthma, particularly inhaled corticosteroids, must be a priority in all countries worldwide.