Grant: Fellowship: Bisby (Prize)

Previous research has shown that physical activity and higher body fat are associated with increased risk of postmenopausal breast cancer. In fact, these two factors may be responsible for up to one third of breast cancer cases. However, the biological pathways responsible for these associations are not clear. Previous research suggests that the body's ability to properly produce and use insulin to regulate blood sugar levels may play a role. This may help explain why women with type 2 diabetes, a condition where insulin and blood sugar are disrupted, also have a higher risk of breast cancer. The Nutrition and Exercise in Women (NEW) Trial is an ongoing clinical trial involving approximately 500 overweight, inactive, post-menopausal women, a group particularly at risk for breast cancer. Eligible women are assigned to participate in either: 1) 1 year supervised aerobic exercise (e.g. walking); 2) 1 year of reduced calorie diet; 3) 1 year of exercise AND a reduced calorie diet; or 4) no intervention. As a post-doctoral fellow, I will analyze the results from the NEW trial in order to examine the separate and combined effects of exercise and weight loss on insulin activity in overweight, inactive, post-menopausal women. This research will help clarify which component of lifestyle (e.g. weight loss or physical activity) is most important for the healthy regulation of blood sugar by insulin and for reducing the risk of breast cancer. Because a high level of insulin is also a risk factor for diabetes and heart disease, the findings will have relevance to several diseases related to obesity. Ultimately, this research will lead to better public health recommendations on exercise and weight loss for the prevention of postmenopausal breast cancer.