Table 1.

Composition of the selected rheumatoid arthritis case and control population samples

Ancestry	Sample origin	Number of cases	Number of controls
Caucasian	Greek	37	31
Caucasian	Spanish	141	234
Caucasian	American (Whites)	206	105
Amerindian	North American (Amerinds)	98	78
African-American	North American (Blacks)	46	51
African	San (Bushman)	23	57
Asian	Korean	81	68
Asian	Chinese	21	20
Asian	Javanese	66	72
Slavic	Russian	40	73
Total		759	789

These data were extracted from the 13th International Histocompatibility Working Group rheumatoid arthritis samples and are available on the National Center for Biotechnology Information website [28]. For the sample selection procedure, please refer to the Materials and methods section of this article.