Objective: Tumor necrosis factor-alpha (TNF-alpha) promoter -308 A/G polymorphism has been reported to be associated with rheumatoid arthritis (RA) with inconsistent results. We investigated whether TNF-alpha -308 A/G polymorphism confers susceptibility to RA.
Methods: We conducted a random effect metaanalysis on the association of genotypes A/A (recessive effect), A/A + A/G (dominant effect), A allele, and A/A vs G/G genotypes of the TNF-alpha -308 polymorphisms with RA overall and within different ethnic populations.
Results: Fourteen studies, 10 of Europeans, 3 of Latin Americans, and one Asian, were included in this metaanalysis. An association between RA and the TNF-alpha -308 A allele was not found in the overall population (OR 1.005, 95% CI 0.715-1.412, p = 0.976). However, stratification by ethnicity indicated that the TNF-alpha A allele was significantly associated with RA in Latin Americans (OR 2.004, 95% CI 1.158-3.467, p = 0.013). Conversely, there was no association detected for the TNF-alpha A allele with RA patients from the European samples (OR 0.911, 95% CI 0.684-1.212, p = 0.520). The OR for the A/A + A/G genotype, the A/A genotypes, and the A/A vs G/G genotypes in samples overall and in each ethnic group showed a similar trend to those for the TNF-alpha A allele.
Conclusion: This metaanalysis demonstrates that the TNF-alpha -308 A/G polymorphism may represent a significant risk factor for RA in Latin Americans, but not in Europeans.