Grant: CIHR Fellowship

Colorectal cancer is the second leading cause of cancer death across the world and the third most common cancer diagnosed among females. Existing research has suggested that lifestyle factors, such as physical activity and diet, modify one's risk of developing colorectal cancer. Recently, evidence has also suggested that the composition of the gut microbiome (bacteria, archaea, fungi, and viruses, and other organisms found in the gut), may be involved in the development of colorectal cancer. However, how lifestyle factors, such as diet, alter microorganisms (i.e., bacteria) in the gut, and how this may then influence the risk of colorectal cancer remains unclear. This project will investigate the associations between lifestyle factors such as diet, body weight, and physical activity with the gut microbiome and risk of colorectal adenomas (a benign growth in the bowel that may become cancerous). Using the MICRObiome among Nurses (MICRO-N) cohort; a cohort of 20,000 female nurses who have provided stool samples and reported their lifestyle and dietary habits over time, we will investigate lifestyle factors associated with the gut microbiome composition. We will also explore gut microbiome features, such as specific bacteria, that may be related to the risk of colorectal adenoma and see if lifestyle factors may interplay with microorganisms in the gut in modifying risk. Understanding lifestyle factors and microbiome features that are related to colorectal adenomas may be important for future screening programs and colorectal cancer prevention.