Table 6.

Estimated joint effect^* of premenopausal hysterectomy or hormone therapy and uterine leiomyoma on the odds of ovarian cancer

	Leiomyoma								Leiomyoma within Strata of effect modifier		RERIa	RERIm
	No				Yes
	N Cases	N Controls	OR†	95% CI	N Cases	N Controls	OR†	95% CI	OR†	95% CI
Premenopausal Hysterectomy
All participants
No	1695	3111	1.00		577	892	1.38	1.21–1.57	1.40	1.22–1.60	−0.41 (−0.74–−0.08) p=0.01	0.71 (0.55–0.91) p=0.01
Yes	311	393	1.29	1.08–1.53	351	516	1.26	1.06–1.48	0.96	0.76–1.21
Black participants
No	435	1049	1.00		268	511	1.48	1.20–1.83	1.53	1.23–1.89	−0.52 (−1.10–0.06) p=0.08	0.66 (0.43–1.00) p=0.05
Yes	75	132	1.33	0.95–1.87	173	338	1.29	1.01–1.66	0.92	0.62–1.36
White participants
No	1260	2062	1.00		309	381	1.29	1.08–1.53	1.31	1.10–1.55	−0.24 (−0.67–0.19) p=0.28	0.81 (0.58–1.13) p=0.21
Yes	236	261	1.26	1.02–1.55	178	178	1.31	1.03–1.66	1.00	0.74–1.35
Hormone Therapy
All participants
No	1292	2448	1.00		529	864	1.30	1.13–1.50	1.33	1.15–1.54	−0.08 (−0.35–0.19) p=0.57	0.93 (0.75–1.16) p=0.50
Yes	729	1054	1.08	0.94–1.23	402	545	1.30	1.09–1.54	1.19	0.99–1.43
Black participants
No	434	978	1.00		320	596	1.37	1.11–1.68	1.37	1.11–1.69	−0.12 (−0.65–0.42) p=0.67	0.89 (0.59–1.35) p=0.58
Yes	83	201	1.17	0.85–1.61	123	254	1.42	1.05–1.92	1.25	0.83–1.87
White participants
No	858	1470	1.00		209	268	1.23	1.00–1.52	1.29	1.04–1.60	−0.02 (−0.37–0.32) p=0.89	0.98 (0.73–1.31) p=0.89
Yes	646	853	1.01	0.87–1.18	279	291	1.22	0.99–1.51	1.18	0.96–1.46

^*Measure of relative excess of interaction on the additive and multiplicative scales.

^†Odd ratios were adjusted for site, age at diagnosis, education, parity, OC duration, BMI, smoking status, tubal ligation, family history of cancer, menopausal status, hormone therapy duration or premenopausal hysterectomy, and age at menarche.