Table 5.

Relationship between human leucocyte antigen-DRB1 shared epitope homozygosity or heterozygosity and risk of anticyclic citrullinated peptide antibody or rheumatoid factor seropositivity

	Total cohort (n = 143)				Blacks (n = 124)
	SS (n = 80)		SX (n = 52)		SS (n = 72)		SX (n = 43)
	OR (95% CI)	P value	OR (95% CI)	P value	OR (95% CI)	P value	OR (95% CI)	P value
RF	7.0 (1.8 to 26.6)	0.0059	6.3 (1.5 to 25.7)	0.0126	4.5 (1.0 to 19.5)	0.0537	4.1 (0.9 to 19.3)	0.0813
aCCP	10.2 (2.6 to 40.3)	0.0010	9.2 (2.2 to 38.9)	0.0028	7.1 (1.6 to 30.4)	0.0121	6.4 (1.4 to 30.1)	0.0223

aCCP = anticyclic citrullinated peptide antibodies; HLA = human leucocyte antigen; RF = rheumatoid factor; SE = shared epitope; SS = homozygous for shared epitope allele; SX = heterozygous for shared epitope allele.