Table 1.

Baseline demographics of study participants by WHI Hormone Trials

	E-alone Trial			E+P Trial
Variable	Breast Cancer n=269	Control n=639	p	Breast Cancer n=528	Control n=1051	p
Oophorectomy status - a part, one, or both ovaries removed, N, %	145, 54.31	375, 58.6	0.06c	21, 4.0	41, 3.6	0.73d
Age, years	63.9 (0.43)	65.3 (0.29)	0.01 a	64.1 (0.29)	64.6 (0.22)	0.16a
BMI, kg/m2	31.3 (0.37)	29.2 (0.22)	<0.0 001a	29.3 (0.25)	28.4 (0.18)	0.001a
Waist circumference, cm	95.1 (0.93)	90.2 (0.51)	<0.0 001a	90.3 (0.57)	87.8 (0.41)	0.0005a
Family History breast cancer, N, %	64, 46.7	101, 37.8	0.09c	110, 45.3	167, 36.0	0.02c
Active treatment assignment, N, %	115, 42.8	323, 50.6	0.03c	310, 58.7	490, 46.6	<.0001c
Age at first birth, N, %
No births	8,3.7	11,2.0		14,3.3	33,3.8
<20 years old	59,27.4	128,23.8		14,3.3	33,3.8
20-<30 years old	139,64.7	321,67.1		286,68.3	640,72.9
30 or more years old	9, 4.2	38, 7.1	0.19c	53, 12.7	85, 9.7	0.24c
Ethnicity, N, %
Amer. Indian/Alaskan	2, 0.7	3, 0.5		1, 0.2	2, 0.2
Native
Asian/Pacific Islander	5, 1.9	10, 1.6		17, 3.2	23, 2.2
Black/African American	39, 14.5	77,12.1		38, 7.2	23, 2.2
Hispanic/Latino	10, 3.7	23,3.6		15, 2.8	26, 2.5
White	213, 79.2	525, 82.2	0.85 d	457, 86.6	940, 89.4
Other	0, 0	1, 0.2		0, 0	0, 0	0.45d
Alcohol intake, N, %
Non-drinker	46, 17.4	81, 12.8		56, 10.8	112, 10.8
Past-drinker	63, 23.9	132, 20.8		91, 17.5	168, 16.2
<1 drink/month	33, 12.5	98, 15.5		72, 13.9	164, 15.8
<1 drink/week
1-6 drinks/ week	46, 17.4	122, 19.2		128, 24.7	297, 28.6
7 or more drinks/ week	29, 11.0	50, 7.9	0.07c	69, 13.3	107, 10.3	0.28c
Current smoker, N, %	20, 7.5	55, 8.7	0.79c	44, 8.5	93, 8.9	0.04c
Parity, children, N, %
Never pregnant	21, 7.8	52, 8.2		44, 8.4	75, 7.2
Never had term	8, 3.0	11, 1.7		14, 2.7	33, 3.2
Pregnancy
1	16, 6.0	39, 6.2		48, 9.2	68, 6.5
2	51, 19.0	114, 18.0		115, 22.0	210, 20.1
3	62, 23.1	143, 22.6		131, 25.1	252, 24.1
4	59, 22.0	123, 19.4		95, 18.2	203, 19.4
5 or more	51, 19.0	152, 24.0	0.64c	76, 14.5	206, 19.7	0.10c
Recreational physical activity, minutes/week (SEM)	132.9 (9.6)	160.3 (7.30)	0.07 b	154.6 (7.56)	171.6 (5.56)	0.08b
Prior E+P use, years (SEM)	2.7 (0.69)	5.2 (1.06)	0.57 b	4.3 (0.55)	3.9 (0.35)	0.70b
Previous hormone use at baseline, N, %
Never used	144, 53.5	331, 519		401, 76.0	782, 74.4
<5 years ago	24, 8.9	73, 11.4		38, 7.2	72, 6.9
5-<10 years ago	17,6.3	29, 4.6		324, 4.6	41, 3.9
10 or more years ago	49, 18.2	125, 19.6		41, 7.8	94, 8.9
Current-user	35, 13.0	80, 12.5	0.62c	24, 4.6	62, 5.9	0.68c

^at-test

^bWilcoxon test

^cChi-square test

^dFisher’s exact test

SEM=standard error of the mean P-values reflect comparisons between cases and controls within each HT trial arm.