Table 2.

Demographic characteristics of the US populations studied in relation to the incidence of IgA nephropathy

Study and Population Details				Racial/Ethnic Compositions of Background Populations
Study Location	Reference Population Size	Age Ranges Included	Median Ages	White, %	Black, %	Hispanic, %	Asian, %	Native American and Alaskan Native	Native Hawaiian and Pacific Islander	Two or More Races	Other, %
Shelby County, Tennessee	200,000	0–18	Not reported	47	49	3	2	0.20%	0.04%	1%	1
Central and Eastern Kentuckya	1 million	9 to >70	Not reported	92	7	0.01	1	<1%	<1%	<1%	1
Olmsted County, Minnesota	3 million	9 to $\ge$80	Not reported	90	3	2	4	0.26%	0.03%	2%	0.92
New Mexico (entire state)	1·8 million	5–86	33	46	2	42	1	10%	0.10%	<1%	0.60
Southern California	>3 million	18–84	42	36	17	36	12	<1%	<1%	<1%	3

^aForty-five counties including Fayette County in Central and Eastern Kentucky. The background population data are drawn from the 1990 census for all of Kentucky.