Table 1.

Characteristics of study population, stratified by ethnicity and case–control status, The Breast Cancer Health Disparities Study (n = 7,733)

	Non-Hispanic Whites (n = 3,030)				p Valuea	Hispanics (n = 4,703)				p Valuea	p Valueb
	Cases		Controls			Cases		Controls
	No.	%	No.	%		No.	%	No.	%
Total subjects	1,431		1,599			2,093		2,610
Study site
4-CBCS	1,177	82.3	1,335	83.5	0.37	579	27.7	736	28.2	0.94	<0.001
Mexico	–		–			816	39.0	994	38.1
SFBCS	254	17.8	264	16.5		698	33.4	880	33.7
Menopausal status
Pre-menopausal	475	34.1	494	31.5	0.13	831	41.2	1,027	40.7	0.71	<0.001
Post-menopausal	919	66.9	1,075	68.5		1,186	58.8	1,499	59.3
Body mass index (kg/m2)c
<25	651	46.1	699	44.4	0.30	482	23.4	453	17.6	<0.001	<0.001
25–29.9	411	29.1	465	29.5		762	37.0	951	36.9
30+	350	24.8	412	26.1		818	39.7	1,172	45.5
History of type 2 diabetes
Yes	91	7.2	122	8.6	0.20	308	16.6	386	16.6	0.98	<0.001
No	1,166	92.8	1,299	91.4		1,548	83.4	1,945	83.4
1st degree family history of breast cancer
No	1071	77.4	1,289	84.5	<0.001	1,799	88.1	2,326	91.8	<0.001	<0.001
Yes	312	22.6	237	15.5		244	11.9	208	8.2
Estrogen/progesterone receptor (ER/PR) status
ER+/PR+	670	68.4	–		–	595	62.1	–		–	0.002
ER+/PR−	115	11.8	–			114	11.9	–
ER−/PR+	15	1.5	–			27	2.8
ER−/PR−	179	18.3	–			222	23.2
Percentage of Native American genetic admixture
≤0.28	1,420	99.2	1,591	99.5	0.21	276	13.2	280	10.7	0.001	<0.001
0.28–0.70	7	0.5	7	0.4		1,373	65.6	1,697	65.0
>0.70	4	0.3	1	0.1		444	21.2	633	24.3
History of menopausal hormone use
Yes	795	69.2	899	69.2	0.98	616	32.5	713	29.5	0.03	<0.001
No	354	30.8	401	30.8		1280	67.5	1,704	70.5
Education level
Less than high school	71	5.0	79	5.0	0.57	1088	52.8	1,538	60.2	<0.001	<0.001
High school grad/GED	284	20.1	338	21.4		377	18.3	419	16.4
College education	1,059	74.9	1168	73.6		594	29.0	597	23.4
Parity
Nulliparous	249	17.6	248	15.7	0.001	225	10.8	181	7.0	<0.001	<0.001
1–2	622	44.0	638	40.3		774	37.2	790	30.5
3–4	441	31.2	529	33.4		729	35.0	997	38.4
5+	102	7.2	167	10.6		353	17.0	626	24.1

	Mean	(SD)	Mean	(SD)	p Valued	Mean	(SD)	Mean	(SD)	p Valued	p Valuee
Age (years)	55.9	11.2	56.7	12.3	0.05	52.7	10.6	52.3	10.8	0.25	<0.001

Missing information: education, n = 121; parity, n = 62; menopausal status, n = 227; menopausal hormone use, n = 971; family history of breast cancer, n = 247; history of diabetes, n = 868; body mass index, n = 107; estrogen receptor status, n = 5797 (cases only)

^aCase–control comparison within ethnicity. p Values from Chi-square tests

^bEthnic group comparison, regardless of case–control status. Mantel–Haenszel Chi-square p values from Chi-square tests

^cBody mass index (BMI) in referent year calculated as kilograms (kg)/meters (m)²

^dCase–control comparison within ethnicity. p Values from t tests

^eEthnic group comparison, regardless of case–control status. p Values from t tests