Table 5. Risk of epithelial ovarian cancer among exclusive users of one hormone type (estrogen only and estrogen plus progestin).

	Estrogen onlya		Estrogen plus progestina
	<5 years use	⩾5 years use	<5 years use	⩾5 years use
All epithelial ovarian tumours
No. of cases	39	43	22	10
Age-adjusted (95% CI)	0.94 (0.66, 1.34)	1.81 (1.28, 2.56)	1.03 (0.64, 1.67)	0.92 (0.47, 1.79)
Multivariateb RR (95% CI)	0.98 (0.68, 1.40)	2.04 (1.41, 2.97)	1.03 (0.64, 1.66)	0.93 (0.47, 1.83)

Abbreviations: RR, relative risk; CI, confidence interval; PMH, postmenopausal hormone.

^aModels include never PMH users and users of one hormone type only (exclusive users of unopposed estrogen and exclusive users of estrogen plus progestin).

^bAdjusted for age, parity, duration of oral contraceptive use, tubal ligation, age at natural menopause and age at menarche.