Prospective Analyses of Sedentary Behavior in Relation to Risk of Ovarian Cancer

We examined the association of sedentary behavior with risk of ovarian cancer overall, by tumor subtype, and by participant characteristics in the Nurses’ Health Study (NHS) and Nurses’ Health Study II (NHS II). A total of 69,558 NHS participants (1992–2016) and 104,130 NHS II participants (1991–2015) who reported on time spent sitting at home, at work, and while watching television were included in the analysis, which included 884 histologically confirmed ovarian cancer cases. Multivariable-adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for ovarian cancer by sitting time (no mutual adjustment for individual sitting types in primary analyses). We examined potential heterogeneity by tumor histological type (type I or II), body mass index (weight (kg)/height (m)2