Table 3.

Exogenous Hormone Use in Association With Ovarian Cancer Risk in the Netherlands Cohort Study on Diet and Cancer, 1986–2002

	No. of Cases	Person-Years in the Subcohort	Age Adjusted		Multivariate Adjusteda
			HR	95% CI	HR	95% CI
OC use
Never	310	25,916.9	1.00	Referent	1.00	Referent
Ever	65	8,668.6	0.67	0.49, 0.91	0.71	0.52, 0.97
Duration of OC use, years
Never	310	25,916.9	1.00	Referent	1.00	Referent
≤5	32	3,246.6	0.87	0.58, 1.31	0.92	0.61, 1.38
>5	22	4,443.2	0.44	0.28, 0.71	0.47	0.30, 0.76
Age at first OC use, years
≤40	31	5,211.8	1.00	Referent	1.00	Referent
>40	32	3,170.7	1.36	0.78, 2.39	1.28b	0.68, 2.43
Age at last OC use, years
≤45	18	2,910.8	0.91	0.51, 1.60	0.51b	0.24, 1.10
>45	42	5,282.9	1.00	Referent	1.00	Referent
HRT use
Never	314	28,679.8	1.00	Referent	1.00	Referent
Ever	44	4,175.4	0.97	0.69, 1.36	0.97c	0.69, 1.37
Age at first HRT use, years
≤50	22	2,114.4	1.00	Referent	1.00	Referent
>50	17	1,500.2	1.10	0.56, 2.18	0.96c	0.47, 1.97
Age at last HRT use, years
≤50	12	1,275.0	1.00	Referent	1.00	Referent
>50	28	2,241.0	1.28	0.61, 2.66	1.39c	0.63, 3.03

Abbreviations: CI, confidence interval; HR, hazard ratio; HRT, hormone replacement therapy; OC, oral contraceptive.

^aAdjusted for age and parity (number of children).

^bAdditionally adjusted for duration of OC use.

^cAdditionally adjusted for duration of HRT use.