TABLE 3.

Distribution of gap time from menopause to first use of postmenopausal hormones among CEE^* users in the clinical trial and observational study according to prior use of postmenopausal hormone therapy by US women, 1993–2004

	Gap time (years) from menopause to first use of HT*
	No prior HT†			prior HT†
	<5	5–15	>15	<5	5–15	>15
Clinical trial participants
% of women by prior HT use	10	32	58	84	12	4
No. of women‡	198	618	1,136	2,129	299	113
No. of breast cancer cases	4	5	21	40	4	2
Observational study participants
% of women by prior HT use	76	17	7	87	11	2
No. of women‡	6,626	1,154	597	1,662	213	30
No. of breast cancer cases	188	36	11	46	5	0

^*CEE, 0.625 mg/day of conjugated equine estrogens; HT, postmenopausal hormone therapy.

^†Prior HT was defined relative to the ongoing CEE episode at Women’s Health Initiative enrollment in the observational study and relative to randomization to CEE in the clinical trial.

^‡Women were selected to have a known time from menopause to first use of HT (refer to the Materials and Methods section of the text).