Grant: Project Grant

Five percent of Canadian women over age 65 have a history of breast cancer (BC) diagnosed within the last 15 years. Compared to 40 years ago, they are now much less likely to die from BC but more likely to die from cardiovascular (CVD), liver and Alzheimer's disease than women without cancer. BC treatment also causes long-term side effects that affect physical and cognitive function. This study aims to test how a new and simple eating pattern called 'time-restricted eating' (TRE) can reduce CVD risk and improve physical and cognitive function. TRE involves eating only during an 8-hour window, such as 11 am to 7 pm each day, and then only drinking water outside those hours. TRE has been shown to reduce CVD risk factors in women without BC, including body fat, blood cholesterol, and blood pressure. These risk factors have also been linked to cognitive and physical function. We will enroll BC survivors who are >60 years old, and have overweight or obesity, and have received cancer treatments that injure the heart. This combination of factors captures the BC survivors who are at the highest risk for CVD. Participants will be randomly assigned, like by the flip of a coin, to perform TRE or to receive standard healthy eating education for 16 weeks. The study team will provide all participants with support to follow their assigned treatment using telephone calls and text messages. We will compare the change in the 10-year risk of developing CVD (calculated from age, cholesterol, and blood pressure) and physical and cognitive function between the two groups after the intervention. We will also assess whether changes in other factors related to CVD risk, including fat around the organs, tissue scarring, and vessel health, are related to the health benefits of TRE. We hope to find that TRE is an easy-to-follow and effective new therapy for reducing CVD risk and improving physical and cognitive function for older BC survivors.