Grant: Doctoral Research Award : Priority Announcement - Primary Prevention of Cancer

In Canada, about 44% of men and 43% of women will develop cancer in their lifetime and it is the leading cause of death. For cancers that affect both sexes (i.e., not cancers such as ovarian or prostate, among others), men are diagnosed more than women for most cancers. The reasons for this difference are mostly unknown, but one recent study found that factors already linked to cancer such as BMI, diabetes, and smoking only explained a modest part of the male predominance in most cancers. But, to the best of my knowledge, many behavioural and environmental factors were not examined to see how much they could explain this male predominance in cancer diagnoses. The aims of my study are to: 1) describe male vs. female sex ratios for new cancer cases in the Canadian population and 2) see if the apparent sex ratio in these cancers is explained by sex differences in known risk factors. To do this study, I will use data from three linked sources: 1) the largest cohort in Canada, which includes more than 300,000 adult participants from eight provinces who have been filling out health questionnaires since 2008/2009; 2) Canadian environmental monitoring data; and 3) provincial cancer datasets, which include data on all individuals in a province diagnosed with and/or receiving treatment for cancer. From these three datasets, the following risk factors will be examined: age, sex, gender, ethnicity, marital status, family cancer history, BMI, physical activity, tobacco use, alcohol use, diet, UV exposure, income, education, other illnesses, neighbourhood relative wealth, and air quality. I will answer my study aims by calculating cancer sex ratios for 19 different physical sites in the body (e.g., lung, colorectal). Separate analyses will be done for transgender men and women. The results of this project will give important information on the different processes whereby men and women develop cancer, which may be used to develop sex-specific guidelines for cancer prevention.