Table 1.

Characteristics of the African-American and white populations in the United States by zip code quintile of median household income

Characteristic	Median Household Income Quintiles					P Value
	Q1 (<$30,962)	Q2 ($30,962–$37,314)	Q3 ($37,315–$44,723)	Q4 ($44,724–$56,580)	Q5 (>$56,580)
African-American population
Population (n)	14 million	8 million	6 million	4 million	3 million
Age (yr)	34±14	33±11	32±11	31±10	31±10	<0.001
Age categories (yr)						<0.001
18–39	47	51	52	52	48
40–59	34	33	33	34	40
≥60	19	16	15	14	12
Female sex	52	51	52	52	51	0.42
Age and sex standardized ESRD rate (pmp)	762	653	594	540	502	<0.001
Residence
Metropolitan	84	86	94	98	99	<0.001
Micropolitan	7	8	5	1	1	<0.001
Rural residence	9	6	1	1	0	<0.001
White population
Population (n)	28 million	39 million	41 million	44 million	46 million	<0.001
Age (yr)	49±4	48±4	48±3	47±3	46±4	<0.001
Age categories (yr)						<0.001
18–39	40	38	39	39	37
40–59	32	34	35	37	42
≥60	28	28	26	24	21
Female sex	52	52	52	52	52	0.41
Age and sex standardized ESRD rate (pmp)	358	319	294	262	215	<0.001
Residence
Metropolitan	49	54	73	91	99	<0.001
Micropolitan	20	23	16	5	1	<0.001
Rural	31	23	11	4	0	<0.001

Data are presented as mean ± SD or percentages, unless otherwise stated. Where not stated, missing values comprised <5% of all values.