Although a large body of evidence shows consistent associations of percent breast density (a risk factorfor breast cancer) with age, reproductive factors, body mass index (BMI) and use of postmenopausal hormone therapy (HT), there are fewer data on associations with modifiable lifestyle factors. Physical activity is among the lifestyle factors that may play a role in breast cancer prevention. And, while epidemiological studies have consistently shown an association between physical activity and a reduction in breast cancer risk, it is unclear whether one of the mechanisms by which physical activity exerts a protective effect is via breast density. Emerging research also suggests that the time one spends physically inactive (i.e.,sedentary) may also play an important role in overall health. Two studies haves hown that self-reported sedentary time is associated with increased breast density in Hispanic women. Interestingly, while sedentary time was significantly associated with density in those studies, physical activity was not. While these findings are promising and indicate another avenue for behavioral intervention (i.e., reducing sedentary time), the relationship between sedentary time and breast density has yet to be widely examined in women of diverse ages and backgrounds.

The Food, Exercise,and Mammography Study (FEMS) is an on-going trial that will enroll 100 women who have recently undergone screening mammography at the Lynn Sage Comprehensive Breast Center of Northwestern University. This study will investigate relationships among physical activity, cardiovascular fitness, time spent sedentary, and breast density. This study expands previous research by adding objective assessments of physical activity, sedentary time, and fitness. In addition, we will examine how nutritional factors such as Vitamin D may also contribute to breast cancer risk reduction.

last updated:Thu Jun 25, 2009 11:57 AM