OBJECTIVE: Candidate gene association studies and genome-wide association 
studies (GWAs) have identified a large number of single nucleotide polymorphisms 
(SNPs) loci affecting susceptibility to rheumatoid arthritis (RA). However, for 
the same locus, some studies have yielded inconsistent results. To assess all 
the available evidence for association, we performed a meta-analysis on 
previously published case-control studies investigating the association between 
SNPs and RA.
METHODS: Two hundred and sixteen studies, involving 125 SNPs, were reviewed. For 
each SNP, three genetic models were considered: the allele, dominant and 
recessive effects models. For each model, the effect summary odds ratio (OR) and 
95% CIs were calculated. Cochran's Q-statistics were used to assess 
heterogeneity. If the heterogeneity was high, a random effects model was used 
for meta-analysis, otherwise a fixed effects model was used.
RESULTS: The meta-analysis results showed that: (1) 30, 28 and 26 SNPs were 
significantly associated with RA (P<0.01) for the allele, dominant, and 
recessive models, respectively. (2) rs2476601 (PTPN22) showed the strongest 
association for all the three models: OR = 1.605, 95% CI: 1.540-1.672, 
P<1.00E-15 for the T-allele; OR = 1.638, 95% CI: 1.565-1.714, P<1.00E-15 for the 
T/T+T/C genotype and OR = 2.544, 95% CI: 2.173-2.978, P<1.00E-15 for the T/T 
genotype. (3) Only 23 (18.4%), 13 (10.4%) and 15 (12.0%) SNPs had high 
heterogeneity (P<0.01) for the three models, respectively. (4) For some of the 
SNPs, there was no publication bias according to Funnel plots and Egger's 
regression tests (P<0.01). For the other SNPs, the associations were tested in 
only a few studies, and may have been subject to publication bias. More studies 
on these loci are required.
CONCLUSION: Our meta-analysis provides a comprehensive evaluation of the RA 
association studies from the past two decades. The detailed meta-analysis 
results are available at: 
http://210.46.85.180/DRAP/index.php/Metaanalysis/index.