Table 1.

Demographic characteristics of study populations

Characteristics	control	RA	P-value
Number of subjects	103	128
Sex, female/male	63/37%	73/27%	0.57
Age, mean ± SD	50.2 ± 12 yr	52.8 ± 11 yr	0.18
Ethnicity			0.62
African American	28.2%	37.5%
White	42.7%	39.8%
Hispanic	22.3%	18.0%
Asian	6.8%	4.7%