Lifestyle Factors and Cancer Prevention: Understanding the Role of Exposure Timing
The Seminars in Epidemiology organized by the Department of Epidemiology, Biostatistics and Occupational Health at the McGill School of Population and Global Health is a self-approved Group Learning Activity (Section 1) as defined by the maintenance of certification program of the Royal College of Physicians and Surgeons of Canada. Physicians requiring accreditation, please complete the Evaluation Form and send to admincoord.eboh [at] mcgill.ca
Anita Koushik, PhD
Director, Division of Cancer Epidemiology
Professor, Department of Oncology, McGill University
WHEN: Monday, November 18, 2024, from 4 to 5 p.m.
WHERE: Hybrid| 2001 McGill College, Rm 1140 | Zoom
NOTE: Anita Koushik will be presenting in-person
Abstract
Cancer has long been known to be a disease of aging. Indeed, the highest proportions of new diagnoses occur in those between the ages of 65 and 74 years. Related to this is that the induction period of cancer development with most causes is long, likely in decades. Thus, to optimize research resources in past cancer prevention studies, researchers have generally measured candidate lifestyle and behavioural risk factors in middle-to-older-aged adults. However, there is increasing recognition that exposures even earlier in life may influence future cancer risk. For instance, early menarche is associated with increased breast cancer risk, and human papillomavirus infection, usually first acquired during teenage/early adult years, is a necessary cause of cervical cancer diagnosed decades later. About 4 in 10 cancers cases can be prevented with current knowledge of lifestyle and environmental factors, but this number could be increased with a better understanding of the role of timing of exposures.
One cancer of critical importance to women’s health is ovarian cancer. It has the highest case-fatality of all gynecologic cancers and will be diagnosed in 1 in 71 Canadian women during their lifetime. Primary prevention efforts are hampered because the etiology is not well understood. Only increasing parity and oral contraceptive use are established as modifiable factors associated with risk reduction. Interestingly, both of these “exposures” occur relatively early in adulthood. Conversely, menopausal hormone therapy, which slightly increases ovarian cancer risk, is primarily used later in adulthood (i.e., during perimenopause). Different risk factors may thus have different effects on ovarian cancer risk depending on the specific life periods of exposure.
This presentation will share the results of our research examining modifiable lifestyle factors, namely vitamin D, body fatness and physical activity, in relation to ovarian cancer risk with a formal consideration of timing of exposure.
Learning Objectives
At the end of this talk, attendees will:
- Understand the gaps in knowledge related to cancer prevention efforts and the potential importance of timing of exposure;
- Become familiar with the utility of the life course approach to epidemiologic research when studying cancer etiology;
- Appreciate the application of the weighted cumulative exposure (WCE) method and the Bayesian relevant life course exposure model (BRLM).
Speaker Bio
Anita Koushik is a Professor in the Gerald Bronfman Department of Oncology, Principal Scientist at St. Mary's Research Centre and inaugural holder of the McGill University Chair in Community Cancer Care at St. Mary’s. Since August 2024, she is Director of the Division of Cancer Epidemiology. Her research program aims to increase our understanding of the etiology of cancer in order to improve primary prevention and risk assessment efforts. She also conducts research on the identification of modifiable factors that can improve prognosis and quality of life of cancer survivors.