Understanding Key Factors Underlying Childhood Asthma and Advocating for Equal Patient Access and Care

Article by Nayaab Punjani

Graphic design by Katrina Hass

Asthma is an inflammatory lung condition that affects one in four Canadian children.1,2 Certain triggers may increase the incidence of asthma attacks – which involve wheezing and shortness of breath – resulting in hospital admissions.1 Currently, 2.3 million Ontarians are diagnosed with asthma, with 50 000 new cases in 2020 alone.2

These statistics prompted Dr. Teresa To’s research pursuit into the epidemiology of respiratory diseases, with an emphasis on childhood asthma. Dr. To is currently a professor of Biostatistics and Epidemiology at the Dalla Lana School of Public Health with an IMS cross-appointment. She is a Senior Scientist in the Department of Child Health Evaluative Sciences at The Hospital for Sick Children, while also serving as a Senior Adjunct Scientist for ICES, an organization that compiles databases examining patterns of healthcare access and use in Ontario.

Dr. Teresa To
Professor in Biostatistics and Epidemiology at the Dalla Lana School of Public Health

Professor at the Institute of Health Policy, Management and Evaluation (IHPME)

Cross appointed Professor with the Institute of Medical Science (IMS)

Senior Scientist, Child Health Evaluative Sciences, The Hospital for Sick Children

Senior Adjunct Scientist ICES/ Scientific Lead from Sick Kids for ICES UofT

Tier 1 Canada Research Chair, Asthma

Lead, Environmental Health Platform, Canadian Respiratory Research Network

Associate Editor, Canadian Journal of Respiratory, Critical Care and Sleep Medicine

Photo Credit: Dr. To

When Dr. Teresa To was first hired by ICES, no one was focused on pediatrics, so Dr. To partnered with The Hospital for Sick Children to study the conditions responsible for hospital admissions. While examining the data from emergency department admissions, she mentions, “One of the top reasons for children being admitted, was asthma…I repeated my analysis to ensure findings were accurate, and it came out the same and it sort of blew my mind, why would kids, even in the late 90s…be admitted for something so treatable?” Over the years she realized the situation is quite complex, requiring consideration of social determinants and access to Canada’s healthcare system.

Dr. To’s research began through the examination of asthma epidemiology to understand factors relating to the incidence of cases, hospital admissions, and causes of death. Dr. To features findings of this research in a website known as OASIS–the Ontario Asthma Surveillance Information System (https://lab.research.sickkids.ca/oasis/).

Dr. To found that one of the key factors contributing to asthma is socioeconomic status. Despite having universal health care access in Canada, we do not have a universal drug plan. She explains,

“Even if you have a drug to treat asthma, if you do not have the money or a drug insurance plan to pay for it, or do not have means to support adherence to the disease management, it is difficult to gain control of [a] condition like asthma.”

Dr. To’s passion for health care access, policy, and environmental impacts fuel her involvement as a Tier 1 Canada Research Chair for Asthma, and a Lead for the Environmental Health Platform of the Canadian Respiratory Research Network. The environmental focus of her work aims to examine the influence of air pollution on the exacerbation of asthma symptoms. One of her published studies found that when exposed to air pollutants, people with asthma were three times more likely to develop chronic obstructive pulmonary disease (COPD), also known as asthma-COPD overlap syndrome (ACOS), which is associated with worsened lung functioning and a significantly higher need for health care services.3

For children, Dr. To aimed to study early life exposures to air pollution and lung health, as the lungs continue to mature until the early 20s. Early life exposure to pollutants – such as nitrogen dioxide and ozone – resulted in a 17% elevation in the risk of asthma development among a cohort of newborns that were followed for an average of 17 years.4 Therefore, Dr. To suggests that being aware of the conditions of the ambient environment (such as air quality level and temperature) will help guide the time and level of outdoor activities. For example, simple lifestyle changes such as avoiding walking with children in high-traffic streets during poor air quality hours, may help protect these children’s delicate immature organs.

Since asthma is a chronic condition, taking medications daily is critical to manage it and prevent asthma attacks. However, people tend to take their medications on an “as-needed” basis. Dr. To aims to help individuals be better informed about asthma and modifiable factors, such as smoking. She employs the use of infographics released via social media to improve outreach and education for youth.

Dr. To also works with health care providers to optimize the quality of care provided to patients. This involves promoting the use of individualized action plans that have three zones—green, yellow, and red. With the red zone indicating severe symptoms and the need to seek emergency medical treatment. She has also developed the Asthma Quality of Care Indicator checklist that ensures consistent quality of care for patients, while also providing doctors with feedback. Furthermore, Dr. To has helped develop a mobile application called BREATHE, which helps patients track their symptoms with a symptom diary and indicates to the user the air pollution levels in the area. There is also a built-in action plan that informs patients the zone (i.e., green, yellow, or red) of their asthma control.

BREATHE App: Tool for asthma patients to analyze environmental factors and track symptoms, in order to develop individualized action plans.

Dr. To’s research involves integrating various techniques and sources of data. This includes statistics generated by linking multiple annual population-level databases housed at ICES, including data on hospital admissions, emergency department visits, outpatient visits, and laboratory testing. She also linked health administrative data to air pollution data obtained from Environment Canada and Health Canada. Through all her research findings, Dr. To aims to advocate for patients and inform the government of the needs of the asthma population. She also joins forces with the Lung Health Foundation every year to lobby at the parliament “for better coverage, for medication, for better care for people with asthma.”

In terms of the future of her research, Dr. To aims to explore a few emerging areas in respiratory health; 1) examine the impact of COVID-19 in people with asthma, 2) better understand and manage severe asthma, 3) focus on the development and progression of asthma in the pediatric population in order to reduce hospitalizations and 4) look at the effect of vaping on the frequency of asthma attacks and exacerbations in younger populations, with funding from the Canadian Institutes of Health Research (CIHR). Her latest findings showed that one in eight e-cigarette users had asthma, and those with asthma had nearly 24% increased odds of having an asthma attack within 12 months. Dr. To hopes to use findings from this research to raise the awareness of the potential harmful health effects of vaping and develop and implement evidence-based strategies to prevent and reduce e-cigarette use, especially in youth.5

Dr. To leaves a few pieces of advice for future graduates and researchers. Regardless of the specific research question that you are trying to answer, it is important to employ an evidence-based approach. Building one’s research foundation based on strong data collection methods, sound analytical tools, and formal research training are all paramount. Furthermore, one needs to appreciate the relevance of “knowledge translation.” Its impact relies on how effective and efficient research findings are translated and transferred to the general public, including patients, health care providers, and the government. “It is not ideal to simply do research and publish papers…that is old school now…it is also our responsibility to pass the findings and information to the public…to the people who need it [and] who can benefit from it,” while also helping contribute to systemic change at the government level.


  1. Asthma Canada. Understanding Asthma [Internet]. Asthma Canada. [cited 2021 May 25]. Available from: https://asthma.ca/get-help/understanding-asthma/
  2. SickKids. THE ONTARIO ASTHMA SURVEILLANCE SYSTEM (OASIS) [Internet]. OASIS. 2021 [cited 2021 May 25]. Available from: https://lab.research.sickkids.ca/oasis/
  3. To T, Zhu J, Larsen K, et al. Progression from Asthma to Chronic Obstructive Pulmonary Disease. Is Air Pollution a Risk Factor? Am J Respir Crit Care Med. 2016 Aug 15;194(4):429–38.
  4. To T, Zhu J, Stieb D, et al. Early life exposure to air pollution and incidence of childhood asthma, allergic rhinitis and eczema. Eur Respir J. 2020 Feb;55(2):1900913.
  5. To T, Zhang K, Terebessy E, et al. Does Vaping Increase the Odds of Asthma? A Canadian Community Health Survey Study. Session TP16: Clinical and research updates on tobacco cessation, vaping, and e-cigarettes. ATS 2021 International Conference, 14-19 May.