Table 1. Weighted characteristics of participants.

	All participants					Caucasian participants					African-American participants
	Cases		Controls			Cases		Controls			Cases	Controls
Variables	N	%a	N	%a	P-valueb	N	%a	N	%a	P-valueb	N	%a	N	%a	P-valueb
Total	1217		1235			856		712			361		523
Sex
Males	720	61.8	689	61.4		495	62.0	439	61.6		225	61.3	250	60.8
Females	497	38.2	546	38.6	0.10	361	38.0	273	38.4	0.07	136	38.8	273	39.2	0.54
Age at reference date (years)
<45	147	10.5	179	10.5		106	10.2	93	10.2		41	11.6	86	11.6
45–54	287	21.6	270	21.6		185	20.0	145	20.0		102	26.1	125	26.1
55–64	372	29.4	350	29.4		255	29.1	205	29.1		117	30.2	145	30.2
65–74	303	27.1	329	27.1		221	28.1	196	28.1		82	24.3	133	24.3
75+	108	11.5	107	11.5	<0.99	89	12.7	73	12.7	<0.99	19	7.9	34	7.9	<0.99
Mean age (years)	59.9		59.9			60.5	60.4		58.5		58.4
Study center
Detroit	1018	83.3	1038	82.7		738	84.9	611	83.9		280	78.6	427	79.0
Chicago	199	16.7	197	17.3	0.57	118	15.1	101	16.1	0.50	81	21.4	96	21.0	0.88
BMI c
<25	240	19.5	366	29.1		172	19.6	216	29.4		68	19.1	150	28.1
25–29.9	436	37.4	493	41.7		310	37.7	294	42.3		126	36.8	199	40.0
30–34.99	298	24.9	221	18.3		210	25.2	126	18.1		88	23.9	95	18.9
35+	230	18.2	147	10.9	<0.001	156	17.6	74	10.1	<0.001	74	20.2	73	13.1	0.01
Smoking status
Never	432	35.3	471	38.4		309	35.8	287	39.9		123	33.9	184	34.3
Occasionald	55	4.7	55	4.0		34	4.2	25	3.5		21	6.2	30	5.4
Regular former smoker	410	34.7	445	38.0		304	36.5	276	39.3		106	29.4	169	34.1
Regular current smoker	320	25.3	264	19.7	0.03	209	23.5	124	17.4	0.05	111	30.5	140	26.3	0.25
History of hypertension
No	500	40.8	718	59.0		398	45.1	445	61.7		102	28.8	273	51.3
Yes	701	59.2	508	41.0	<0.001	445	55.0	262	38.3	<0.001	256	71.2	246	48.7	<0.001
Education level
<12 years	200	16.7	165	12.0		103	12.7	65	9.4		97	28.1	100	19.1
High school graduate	419	34.5	390	31.5		315	36.6	214	30.8		104	28.7	176	33.5
Some college	328	26.3	356	27.3		215	24.9	184	25.6		113	30.3	172	32.1
College graduate	270	22.5	324	29.3	<0.001	223	25.9	249	34.2	0.001	47	12.8	75	15.3	0.01

Abbreviation: BMI=body mass index.

^aA sample-weighted frequency distribution.

^bP-value from sample Wald F-test.

^cBMI 5 years before interview.

^dSmoked 100 cigarettes in the lifetime, but never smoked at least 1 cigarette a day for 6 months or longer.

The following data are unknown: BMI (eight Caucasian cases, two Caucasian controls, five African-American cases, six African-American controls), history of hypertension (thirteen Caucasian cases, five Caucasian controls, three African-American cases, four African-American controls).