Leisure-time physical activity, sedentary behavior, and risk of breast cancer: Results from the SUN (‘Seguimiento Universidad De Navarra’) project

Evidence is still limited on the influence of sedentary lifestyles breast cancer (BC) risk. Also, prospective information combined effects both sedentariness and leisure-time physical activity (LTPA) scarce. We aimed to assess association higher behavior LTPA (separately in combination) with risk BC a middle-aged cohort university graduates. The SUN Project follow-up study initiated 1999 recruitment permanently open. Baseline assessments included validated questionnaire habits. Subsequently, participants completed biennial questionnaires. Multivariable adjusted Cox models were used estimate hazard ratios (HR) for incident according LTPA, TV-watching, joint classification both, 8-item multidimensional active lifestyle score. 10,812 women, 11.8 years median of. Among 115,802 women-years follow-up, we confirmed 101 cases BC. Women highest category (>16.5 MET-h/week) showed significantly lower (HR = 0.55; 95% CI: 0.34–0.90) compared women lowest (≤6 MET/h-week). watching >2 h/d TV sh owed 1.67; CI:1.03–2.72) than those who watched <1 h/d. (6–8 points) score 0.35; 0.15–0.79) (<2 group. There was no significant supra-multiplicative interaction between TV-watching LTPA. Both low may substantially increase risk, independently each other.