PHS Insider - Susanna Abraham Cottagiri

| 19 October 2026

Susanna Abraham Cottagiri's public health journey began with her master's in Applied Public Health at Cardiff Metropolitan University in Wales, UK. After completing her degree, she worked as a Junior Research Fellow at the Indian Institute of Public Health in Gandhinagar, India. She contributed to several research projects, including a study on climate and the incidence of enteric fever. This experience sparked her interest in environmental epidemiology.

After immigrating to Canada in 2019, Susanna joined Dr. Paul Villeneuve's lab at Carleton University as a researcher. There, she worked on several projects exploring how built-environment features such as greenness and walkability may influence different health outcomes. Susanna then decided to apply for a PhD in Public Health Sciences at Queen's University and was accepted into the program with the support of Dr. Villeneuve and a Canadian Institutes of Health Research grant obtained by Dr. Villeneuve.

Research on thyroid cancer and ionizing radiation

Susanna's PhD research focuses on thyroid cancer incidence and exposure to low doses of ionizing radiation among people living near nuclear power plants. Her thesis aims to examine this relationship using large, population-based Canadian cohorts.

Communities living around nuclear power plants are often concerned about potential cancer risks associated with radiation exposure. Yet, much of the current evidence comes from ecological study designs, which have a number of methodological limitations. The thyroid gland absorbs iodine from the bloodstream to produce hormones that regulate metabolism and energy; however, it cannot distinguish between stable iodine and radioactive iodine. As a result, radioactive iodine that is inhaled or ingested can accumulate in the thyroid and lead to internal radiation exposure.

Susanna's thesis uses five Canadian Census Health and Environment Cohorts, also known as CanCHECs. These cohorts are based on the census years of 1991, 1996, 2001, 2006, and 2011. Combined, they include more than 17 million individuals.

The linked health and mortality data provide long-term follow-up of cancer outcomes. Residential postal code histories from tax records allow for the assignment of annual doses of ionizing radiation for those living near the plants, based on an exposure surface created by a team at Dalhousie University. The postal code histories also allow for residential mobility to be accounted for during the follow-up period.

For Susanna, working with a dataset of this size has been one of the most valuable parts of her PhD. "I really enjoy working with data, and this program has given me the opportunity to further develop my analytical skills as an epidemiologist," she said.

Before beginning her PhD, the largest dataset she had worked with was the Canadian Longitudinal Study on Aging, which includes a little over 50,000 individuals. Now, working with the much larger CanCHEC cohorts she has gained experience managing large administrative and population-based datasets.

Mentorship and other experiences

Susanna is supervised by Dr. Paul Villeneuve and Dr. Will King. Dr. Villeneuve specializes in environmental epidemiology, while Dr. King specializes in cancer epidemiology.

Throughout her PhD, both supervisors have supported her as she navigated complex data and analytical challenges. They have also invested a significant amount of time in her training over the past five years, which she is grateful for.

Beyond her thesis work, Susanna worked for multiple terms as a student researcher with the Public Health Agency of Canada through the Federal Student Work Experience Program. She contributed to projects on mental health and the built environment, functional limitations among older adults with diabetes during COVID-19, and the validation of a diabetes risk questionnaire. She also worked as a teaching assistant for Leading Evidence-Informed Action (EPID 805) with Dr. Sam Buttemer. These opportunities allowed her to work in different areas of population health and broaden her experience as an epidemiologist.

Susanna describes the Queen's Public Health Sciences community as close-knit and welcoming. As a PhD student, she found faculty members, staff, and students to be approachable and willing to help each other.

A day in the life of a PhD student

The structure of Susanna's PhD has changed considerably over time. The earlier part of the program was more structured, with a focus on completing required courses, comprehensive examinations, proposal development, and the proposal defence.

The latter part of the PhD has been more independent, concentrating on completing analyses and writing her thesis and manuscripts.

Her daily schedule depends on the type of work she is doing. On days when she is completing data analysis, she goes to the Statistics Canada Research Data Centre in Ottawa. On days when she is reading, writing, or revising her work, she is usually able to work from home or at a library.

For future students considering attending graduate school, Susanna recommends choosing a topic or research area that they are genuinely interested in.

"There were so many variables that were outside my control during my PhD—excuse the pun—but staying interested in the topic kept me going," she said.

Looking ahead

Susanna is particularly interested in environmental exposures, environmental justice, and understanding the population-level burden of different exposures. After completing her studies, she hopes to continue working with an environmental protection agency.

Outside of her research, Susanna enjoys long hikes and walks with her husband, Owen and her dog, Skye. She also used to do pottery, although finding time for it has been difficult during her PhD. She hopes to return to it after completing her degree.

Author: Michelle Yoo

Interviewers: Anushka Saini and Naomi Kudo

Editors: Isabella Tsan, Naomi Kudo and Surabhi Velagala

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PHS Insider - Susanna Abraham Cottagiri

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