Figure 1.

Association between hysterectomy for a benign indication and invasive epithelial ovarian cancer, by (A) period of hysterectomy and (B) age at hysterectomy, compared to no hysterectomy. Time was censored at hysterectomy for malignancy. Hysterectomy is time-varying. Ovarian cancer includes primary ovarian, fallopian tube, and peritoneal cancer. Models were stratified by decade of birth and adjusted for age at study entry, tubal ligation (yes/no), and parity (3 or more vs 0–2 births). In (B), patterns were similar if we assigned birthdate at the electoral birth-year band midpoint.