Sedentary time and breast cancer incidence in African American women

The objective of this study was to evaluate whether time spent sitting at work or watching television was associated with breast cancer risk among African American women. The Black Women’s Health Study (analytic cohort = 46,734) is an ongoing prospective cohort study of African American women ages 21–69 at baseline (1995). Questionnaire data were used to estimate sedentary time. Total time spent sitting at work and watching television (individually and combined) at baseline and updated through follow-up (1995–2001) and breast cancer incidence (n = 2,041 incident cases, 1995–2013) was evaluated using proportional hazards regression. Higher total time spent sitting at baseline (≥10 vs.