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Dr. Julia Knight
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Dr. Julia Knight


Research Institute
Mount Sinai Hospital
Joseph & Wolf Lebovic Health Complex
60 Murray Street,
Room 5-237, Box 18
Toronto, Ontario
Canada M5T 3L9

Tel: 416-586-4800 ext.8701

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The LEGACY Girls Study


Dr. Julia Knight

Breakthroughs in early detection and treatment of breast cancer have reduced the mortality rate for the disease by 25% since 1986, but 102 Canadian women will still die of breast cancer every week this year. By understanding the lifestyle and genetic factors that impact on breast cancer risk, Dr. Knight hopes to help prevent the disease from happening in the first place.

A Senior Investigator, Leader of the Prosserman Centre for Health Research, Head of the Henry S. Rosenberg Program in Epidemiology and Biostatistics at the Lunenfeld-Tanenbaum Research Institute, and a Professor in the Dalla Lana School of Public Health at the University of Toronto, much of Dr. Knight's work has focused on the role that environmental and genetic factors play in the risk of developing breast cancer.

Dr Knight released a study in 2007 that linked reduced breast cancer risk with increased vitamin D intake. The results were particularly interesting because they suggest that even though breast cancer often occurs at menopause or later, exposure to vitamin D may be most relevant to preventing the disease if taken during breast development.

In a study that focused on what influence melatonin has on breast cancer, Dr. Knight and her group discovered an additional link when they showed that that physical activity appears to increase melatonin levels, which decreases risk for breast cancer.  Melatonin is a hormone produced at night and its production has been linked to cancer in several ways. In contrast, shift workers, who have a decreased level of melatonin, have been shown to have a higher risk of breast cancer.

Currently, Dr. Knight is working with Dr. Irene Andrulis, Senior Investigator at the Lunenfeld-Tanenbaum, to understand the influence of behavior, environment and diet on pubertal growth in girls aged six to 13 and how these factors might impact their risk of breast cancer later in life. The LEGACY Girls Study is  the largest breast cancer study of its kind in Canada. Funded by the U.S. National Institutes of Health (NIH), the LEGACY Girls Study will potentially create a recipe for a number of preventive measures that girls can follow as early as age six, in order to reduce their risk for breast cancer in the future.





At a Glance

  • Dr. Julia Knight studies breast cancer prevention in populations, leads the Prosserman Centre for Health Research, and is Head of the Henry S. Rosenberg Program in Epidemiology and Biostatistics. 
  • She focuses on environmental and genetic factors in the risk of developing breast cancer.
  • She has found strong evidence to support the theory that vitamin D could help to prevent breast cancer.
  • Leader of the Prosserman Centre for Health Research at the Lunenfeld-Tanenbaum; Head, Henry S. Rosenberg Program in Epidemiology and Biostatistics, and Professor, Dalla Lana School of Public Health
    University of Toronto


Major Research Activities

Dr. Knight's team investigates the genetic and non-­genetic causes of cancer, particularly breast cancer, in human populations. Her focus is on using epidemiological approaches to understand gene/­environment interactions in complex systems and the role of risk factors during breast development. Current specific factors of interest include vitamin D, alcohol, and melatonin.


Recent Publications



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Ontario Health Study Faculty of Medicine, University of Toronto. mitacs honorary partner


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