Table 3.

Characteristics of REGARDS Renal Ancillary Study Participants by Anemia Status, Overall and by Race, United States, 2003–2007

Characteristica	Anemia					Anemic Subjects by Race
	No (n = 17,027)		Yes (n = 2,809)		P Value (Anemia vs. no Anemia)	White (n = 976)		Black (n = 1,833)		P Value (White vs. Black)b
	No.	%	No.	%		No.	%	No.	%
Demographics
Age in years, mean (SD)	64.1 (9.7)		66.6 (10.4)		<0.001	69.2 (10.5)		65.3 (10.1)		<0.001
Female gender	10,489	62	1,851	66	<0.001	558	57	1,293	71	<0.001
Living in the southeast	9,999	59	1,771	63	<0.001	652	67	1,119	61	0.003
Socioeconomic variables
High school education	15,306	90	2,290	82	<0.001	884	91	1,406	77	<0.001
Annual income					<0.001					<0.001
<$25,000	2,670	18	675	28		147	18	528	34
$25,000–$75,000	6,508	44	1,152	48		414	50	738	48
>$75,000	5,701	38	560	23		275	33	285	18
Medical conditions
Vascular disease	3,245	19	833	30	<0.001	358	37	475	26	<0.001
Diabetes	2,852	17	1,074	38	<0.001	322	33	752	41	<0.001
Hypertension	9,212	54	2,012	72	<0.001	612	63	1,400	77	<0.001
Ever smoker	8,992	53	1,355	48	<0.001	500	51	855	47	0.019
Body mass index in kg/m2, mean (SD)	29.2 (6.2)		30.5 (7.1)		<0.001	28.5 (6.4)		31.5 (7.3)		<0.001
Anemia-associated conditions
Chronic kidney disease	1,368	8	727	26	<0.001	334	34	393	22	<0.001
Inflammation	1,366	8	482	17	<0.001	134	14	347	19	<0.001
Mean corpuscular volume					<0.001					<0.001
Low (≤80 fL)	553	3	517	19		109	11	408	22
Normal (81–99 fL)	15,993	95	2,195	79		815	84	1,380	76
High (≥100 fL)	327	2	74	3		42	4	32	2

Abbreviations: REGARDS, REasons for Geographic And Racial Differences in Stroke; SD, standard deviation.

^aDefinitions are provided in the Materials and Methods section of the text.

^bP values reflect black-white differences in those with anemia, taking into account the different prevalences of the conditions by race in the entire cohort.