Dr. Teresa To: A Lifelong Commitment to Asthma Research

Dr. Teresa To is regarded as a pioneering figure in the field of asthma research. Throughout her career, she has significantly advanced our understanding the epidemiology of asthma in Canada. She is widely recognized as one of the first to utilize large-scale population data to study asthma, a groundbreaking approach that has played a key role in improving both asthma care and our overall understanding of the condition.

Dr.  To’s path in science has been driven by a thirst for knowledge and a profound desire to make a difference. Born and raised in Hong Kong, Dr. To has spent more than half her life in Canada and proudly calls Toronto home.

Dr. To is a senior scientist at the Research Institute of the Hospital for Sick Children and Professor at the Dalla Lana School of Public Health, University of Toronto. Reflecting on her academic journey, she shares, “I may be one of the rare ones in my time who went straight from kindergarten to a PhD without ever working in between. I was always academically focused, but I wasn’t necessarily set on becoming an academic.” Her early academic years were fueled by a drive to learn, but it wasn’t until a pivotal conversation with her father that her true calling emerged.

After graduating from university, Dr. To recalls asking her father if she could go to Africa to help those in need. “He stopped reading the newspaper and asked me, ‘What can you do to help them?’” she remembers. “I realized I had no practical skills. I could do math, write in Chinese and English, but my dad pointed out that none of those skills were useful for the people I wanted to help.” Her father’s words struck a deep chord: “It sounds like you don’t know much and can’t do much. Maybe you should go back to school and learn more?” This conversation cemented her decision to continue her education and ultimately shift her focus to asthma research.

When she first joined SickKids, Canada’s most research-intensive hospital and the largest centre dedicated to improving children’s health in the country, Dr. To was tasked with assessing the burden of asthma in Ontario, a task she initially thought would be straightforward. “I thought it would be a simple task—just counting numbers and reporting them. But when I saw the numbers, I was shocked. So many kids were being hospitalized for asthma. In fact, asthma was the number one reason children were admitted to the hospital.” It was this moment that sparked her commitment to asthma research. She shares, “When I realized that asthma wasn’t as minor as I had thought, I decided to focus my career on it. I went to my boss and said, ‘I want to focus on asthma. This will be my research territory.’”

Dr. To’s dedication to understanding the complexities of asthma is reflected in her decades-long commitment to the field. She holds a Tier-1 Canada Research Chair in asthma and is a Canadian representative to the WHO Global Alliance Against Respiratory Diseases (GARD).  “Asthma isn’t an simple disease. It’s incredibly complex, which makes it both challenging and fascinating for me. Even now, more than 20 years later, I’m still intrigued. I still want to understand what causes asthma and, more importantly, how we can do better for the people living with it.”

In her career, Dr. To has focused on quantifying the burden of asthma, particularly through the use of large-scale population data. “I was one of the few researchers in Canada to use big data—not just small clinical trials with a hundred patients—to quantify the burden of asthma,” she explains. These insights have helped define asthma’s impact on health systems and on individuals, setting the stage for more targeted interventions.  Using big data, Dr. To founded the Ontario Asthma Surveillance Information System called OASIS and is currently the Scientific Director of OASIS.  Asthma statistics published by OASIS is cited nationally and internationally by others.  “In Ontario, we see between 30,000 to 50,000 new cases of asthma each year. Of those, around 10,000 people are hospitalized and over 30,000 visited the emergency department for asthma annually. These numbers help us understand the magnitude of the issue and allow us to set targets.”

Dr. To is the research lead of the Environmental Health Platform of the Canadian Respiratory Research Network (CRRN). Over the years, Dr. To’s research has expanded to examining environmental factors that exacerbate asthma, such as air pollution. “Some people say, ‘Toronto has good air compared to places like Beijing,’ but air pollution still fluctuates throughout the year, and summer air quality can be particularly bad, and now in addition to air pollution, we also have wildfires” she points out. Her work demonstrated how air pollution increases the risk of asthma attacks and exacerbates the progression to chronic obstructive pulmonary disease (COPD), a major finding published in the American Journal of Respiratory and Critical Care Medicine. “We found that if someone with asthma is exposed to significant air pollution, their risk of asthma attacks more than doubles.”

In addition to air pollution, Dr. To has turned her attention to newer public health threats, such as vaping and cannabis use, especially among youth. “A lot of young people think vaping is harmless compared to cigarettes. But vaping can lead to long-term respiratory issues and mental health challenges—conditions that you have to live with every single day.” She stresses the importance of doctors, especially pediatricians, asking young asthma patients about their vaping habits. “A nine-year-old comes in for an asthma check-up, and it doesn’t even cross their doctor’s mind to ask, ‘Do you use e-cigarettes?’ But the reality is, due to “easy” access, many of them do. That’s why it’s crucial for healthcare providers to start asking these questions.”

Dr. Teresa To’s collaboration with Asthma Canada highlights the value of partnership in asthma research. “I’ve always been a strong supporter of Asthma Canada, but in recent years, they’ve helped me more than I’ve helped them,” she shares. This was especially evident in her project on biologics for asthma treatment. “Asthma Canada contributed one-third of the funding for our research, which focused on how biologics are being used in asthma care. We wanted to know if biologics are effective, how much benefit they provide, whether they’re cost-effective, and importantly, if there are people who need them but aren’t receiving them.”

Dr. To credits Jeff Beach for his key role in securing the support that made the project possible. For her, working together is essential: “We can’t do this work in isolation. Partnerships are crucial to improving outcomes for those living with asthma.” Through her collaboration with Asthma Canada, Dr. To continues to make significant strides in asthma research and care.

Despite her substantial contributions to the field, Dr. To remains humble about her impact. “I don’t think I’ve made a huge impact on the world—it’s not like I discovered the CF gene or found a gene for asthma. What I have done, though, is contribute in smaller ways that help paint a clearer picture of asthma’s impact.” Nevertheless, she remains deeply committed to continuing the work of improving asthma care and research. “We’re still not done with asthma. Ten years ago, funding shifted toward COPD, and now lung cancer is receiving a lot of attention. But asthma is still here, we have not eradicated asthma, yet, and it’s still affecting a huge number of people.”

Looking to the future, Dr. To urges young people entering asthma research to continue fighting for funding, despite the challenges. “Young clinicians and researchers often go into cancers, cardiovascular diseases or diabetes because that’s where the funding is. But asthma doesn’t have the same financial backing, and that makes it harder to do impactful research. We need to start investing more in asthma research.” She concludes with an optimistic note: “There’s still so much potential in asthma research. We need more support, and I want to give people hope that we can make a real difference.”

Dr. Teresa To’s work continues to showcase the complexities of asthma and its impact on millions of lives, and her research offers critical insights into improving the care and lives of people living with asthma.

If you have questions on managing your asthma and allergies during wildfire season, please contact our free HelpLine at 1-866-787-4050 or info@asthma.ca. Our team of asthma and allergy experts will happily assist you with your asthma control and help put your mind at ease.