Association between transforming growth factor-beta1 T869C polymorphism and rheumatoid arthritis: a meta-analysis.

Objective: The results of studies on association between TGF-beta1 T869C polymorphism and susceptibility to RA are controversial. The absence of a replication of linkage might be due to different ethnicities. The aim of this study was to perform a preliminary investigation on the effect size of TGF-beta1 T869C polymorphism on RA susceptibility through a meta-analysis.

Methods: Case-control studies on the association of TGF-beta1 T869C with RA were searched up to March 2009, and the genotype frequencies in the control group were found to be consistent with the Hardy-Weinberg equilibrium. The effect summary odds ratio (OR) and 95% CIs were obtained. Publication bias was tested by funnel plot with Egger's regression test, and heterogeneity was assessed.

Results: Seven studies comprising 1122 cases and 1132 controls were included. Heterogeneity was observed (chi(2 )= 17.16; P = 0.009). Under the random effects model, the common OR was 1.38 (95% CI 0.95, 2.01; P = 0.09). In the subgroup meta-analysis, there was an association between TGF-beta1 T869C polymorphism and RA in the people of Asian descent (OR = 1.93; 95% CI 1.42, 2.62; P < 0.0001), but not in the people of non-Asian descent (OR = 0.88; 95% CI 0.65, 1.19; P = 0.41). There was no evidence of publication bias according to Funnel plot and Egger's regression test (a = 4.778; P = 0.14).

Conclusions: There was heterogeneity between studies, and no clear evidence of an association on a worldwide population was observed. Subgroup analysis results suggest that TGF-beta1 T869C might play a role in RA susceptibility for Asians but not for non-Asians. Further studies are required for definite conclusions.